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Amy Hillier University of Pennsylvania School of Design Cartographic Modeling Lab
IntroductIon to thIs Manual
This manual is intended for undergraduate and graduate students learning to use ArcView 9 in a classroom setting. It is meant to be a complement, rather than substitute, for ArcView software manuals, ESRI training products, or the ArcView help options. It reflects the order and emphasis of topics that I have found most helpful while teaching introductory GIS classes. I expect that it will be particularly helpful to people new to GIS who may be intimidated by conventional software manuals. It may also be helpful as a resource to those who have completed a course in ArcView but don’t always remember how to perform particular tasks. This manual does not try to be comprehensive, focusing instead on the basic tools and functions that users new to GIS should know how to use. Those who master these basic functions should have the skills to learn about additional tools, using the ArcView help menus, or just exploring additional menu options, toolbards, and buttons. Each section in the manual introduces a general group of functions in ArcView, providing step by step instructions for using a set of tools with screen captures and a video showing those steps through screen captures. I have created a separate workbook with exercises and data for working through these activities because most of us need hands-on practice before the functions make sense. One of the most difficult parts of learning how to use GIS is matching what you know you want to do in layman’s or conceptual terms to the specific tool and technical language of ArcGIS. The table of contents provides an overview of the tools and functions covered, but you may find it just as helpful to use Adobe Acrobat’s “find” function.
Graphic Design by caitlin Bowler, McP ‘08
The other challenge is trouble-shooting. ArcGIS products include an enormous range of functionality which allows it to meet the needs of a wide range of users. But this wide range also results in what can be an overwhelming and sometimes temperamental product. Figuring out why things don’t work is key to getting ArcGIS to do what you want it to do and minimizing your frustration. The section on trouble-shooting at the end of this manual is intended to help identify common problems and solutions. This manual is intended to be shared. You do not need my permission to share this with a friend or even post it on a course website. Because I am continually updating it, I always appreciate feedback, whether you found a typo or spelling mistake or want to suggest a better way of explaining particular concepts and techniques. The best way to succeed with GIS is to make learning how to use it a collective process, so please join me in making GIS work for us.
Amy Hillier University of Pennsylvania firstname.lastname@example.org
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9 . 3
table of contents
Introduction to ArcGIS Introduction to ArcCatalog Introduction to ArcMap Managing & Saving Files Data Formats 2 5 10 19 22
4| ModIfyIng attrIbutes
Working with Tables Calculating Values Calculating Area, Perimeter & Length Creating XY Coordinates Joining Tables Adding Hyperlinks 58 60 63 66 69 71
7| creatIng new geographIc fIles
Editing Shapefiles Transforming Map Layers 89 91
Creating Shapefiles 95
2| spatIal data
Working with Projections Georectifying Images 26 31
5| creatIng & aggregatIng poInt layers
Geocoding Addresses 73 79 Spatial Joins
9| workIng wIth 3d
3D Analyst 99
3| MakIng Maps
Symbolizing Point Data Symbolizing Area Data Labeling Features Designing Map Layouts Making Inset Layouts Exporting Maps 35 38 45 49 54 56
10| anIMatIng tIMe serIes data
Animation Toolbar Tracking Analyst 103 105
6| QueryIng & MeasurIng
Querying by Attribute Querying by Location Measuring Creating Buffers 82 84 86 87
Cartogram Script 107 109
and online GIS products. ArcView ArcView is the desktop version of ArcGIS meant for a general (non-professional) audience. It is the most popular desktop GIS software program. adding some advanced geoprocessing and data conversion capabilities. and author maps. ArcReader ArcReader is a free product for viewing maps. but the two versions work in a very similar way. but the products work in very different ways. hosted. ESRI brought ArcView into its ArcGIS system so that it uses the same structure as its more sophisticated GIS products. A matrix describing what functionality is available for each product is available at http://www. adding the ability to edit Map made by Shimrit Keddem features in a multiuser geodatabase so that multiuser editing and versioning are possible.x. 2 .1| IntroductIon to ArcGIS ArcGIS is a collection of software products created by Environmental Systems Research Institute (ESRI) that includes desktop. You can explore and query map layers. but you cannot change symbology or create new data like you can in ArcView. ArcEditor also adds the ability to edit topologically integrated features in a geodatabase. That means that if you learned GIS using ArcView 3. ArcEditor ArcEditor includes all the functionality of ArcView. ArcReader is a good way to share the maps you created in ArcView with people who don’t have access to the software. server. you will probably need to do some work to be able to use ArcView 9.com/library/brochures/pdfs/arcgis92-functionality-matrix. Some people will call this “ArcGIS” rather than “ArcView. With the jump from ArcView 3. you should have no trouble switching to ArcView 9. ArcView 3. deSktop gIS productS The desktop GIS products allow users to integrate and edit data.2 to ArcView 8. so if you learned how to use ArcView 8. 2 H I l l I E R | U S I n G A R c V I E w 9 . only. it is still over-kill for many simple GIS projects. so it is a more specific way to describe the software. This introduction provides an overview of all of the products. ArcView is part of the ArcGIS collection. but this manual focuses on the desktop applications. It includes all of the functionality in ArcView and ArcEditor. mobile.” They are one in the same.esri. create new map layers. ArcInfo ArcInfo is ESRI’s professional GIS software. ArcView 9 adds some functionality to ArcView 8.pdf.x has similar functionality to ArcView 8. Even though it is the “baby” desktop GIS product within the ESRI family of products. but the more expensive products have more functionality. but it is not the only one. ArcGIS desktop includes a series of scaleable products. They are all based on the same architecture.
extensions can also be purchased (some are free) that extend this functionality. Model made by Shimrit Keddem I n T R o d U c T I o n 3 . This includes extruding polygons (such as parcels and building footprints) and draping surfaces (such as orthophotos) on elevation models. You can also create video animations that simulate flying through your study area. Allows users to view visualize and analyze spatial data in 3D. Network Analyst Allows for network-based analysis such as routing.S. Many of these are specific to particular industries or data formats. Methods include Kriging and inverse distance-weighting. and service areas. Business Analyst Designed to support business decisions through a series of advanced tools and extensive collection of industry data. determining closest facility. Streetmap Makes possible geocoding of street addresses for the entire U. CommunityViz Designed for visualizing and analyzing land-use decisions. This product is distributed by Placeways rather than ESRI. Unlike simple representations of street networks that can be manipulated without this extension. You can view events happing across time and space using the “playback” feature. one-way streets. Tracking Analyst Makes it possible to animate point data representing events at discrete times and places. networks can store information about traffic flow. street addresses generally need to be mapped one county at a time. and travel time.extenSIonS for arcgIS deSktop While the basic ArcGIS desktop products include an enormous amount of functionality. This includes creating density surfaces and conducting map algebra. 3D Analyst Includes ArcGlobe. The following are some of the more frequently used extensions. Spatial Analyst Allows for modeling and analysis with raster (cell-based) data. When using ArcGIS without Streetmap. Geostatistical Analyst This sophisticated tool allows users to analyze raster (cell-based) and point data using advanced statistical methods.
but distributing GIS data. This is critical in a work setting as well as when you wish to serve maps on the internet. 4 H I l l I E R | U S I n G A R c V I E w 9 . sort of the Microsoft of GIS. Microstation This is Bentley’s engineering design platform that incorporates GIS functionality through a number of different products. MapInfo is much simpler than ArcView for working with demographic data. or Avenue (the old programming language for ESRI) by users or ESRI staff members. This is ESRI’s version of Google Earth. ArcGIS products can also be used with global positioning systems (GPS). processing. MobIle gIS productS These are useful for collecting data in the field. ArcGIS Explorer Lightweight product that comes with ArcGIS Server. which allow users to identify the longitude and latitude coordinates of particular locations in the field. Many colleges and universities have site licenses for ESRI products. so GIS classes often use ESRI products. maps. and spatial analysis in an “enterprise” (large-scale user) setting. Other GIS products worth exploring include: ArcGIS Server Used for data management. visualization. Server gIS productS Desktop GIS is ideal for individual use (appropriate for classroom learning and small-scale research projects). A large collection are available for free at http://arcscripts. MapInfo This family of products sold by CMC International can do much of what ESRI products can do. These are generally written in Visual Basic. other gIS productS ESRI is the leading GIS software maker. which is increasingly common. ArcPad must be customized through programming. and tools requires server GIS products. ArcIMS Used to create applications that deliver maps and data via the Internet.Scripts for ArcGIS Desktop Extensions are simply bundles of scripts that are added together to ArcGIS. and distributing image data in a server environment. Individual scripts can also be added without purchasing whole extensions. ArcPad includes many of the same functions as ArcGIS destop products and can be installed on a pocketPC. The size of the hardware and the display screen limits how much functionality can be included. provides access to GIS content. ArcGIS Image Server Needed for managing. Python. GRASS GIS Geographic Resources Analysis Support System (GRASS) is free GIS software that is increasingly popular among proponents of open-source software.com/. 2 .esri. supports 2D and 3D maps and geoprocessing.
lines.txt” icon shows that it is a text file. Using ArcCatalog may seem awkward. click on the ArcCatalog button (looks like a file cabinet) from the Standard toolbar. This is an aerial Recognizing File Types ArcCatalog will recognize files that are ready to be mapped using special icons. particularly to people who are familiar with ArcView 3. ArcGIS. corresponding to the location of all the hospitals in Pennsylvania. “cancer_pa. The icon for “PA_major_roads. ArcView 9. The “cancer_pa. ArcView can also read Excel (. or pixel.. which happen to be all photograph where each cell. corresponds to 1 meter on the ground. If ArcView is open. The income for the file named “cancer. In this case. the files in the “Pennsylvania” folder named “cancer_pa. corresponding to each section of the state and federal highways in Pennsylvania.xls) files. I n T R o d U c T I o n 5 .020. or polygons. in this case a dBase file.IntroductIon to arccatalog ArcCatalog is designed to help you manage your spatial and non-spatial data.1 and previous versions are capable of reading tables formatted as . The file named “cancerp020. but using ArcCatalog will help you to develop good GIS habits. You can launch ArcCatalog from the Start Menu (go to All Programs. then ArcCatalog) or from ArcView. Launching ArcCatalog ArcCatalog is a separate executable (.dbf” indicates that it is a table. ArcCatalog is an ideal place to first view your spatial data and supporting documentation.exe) file from ArcMap. made up of a regular grid of cells.” “hospitals_pa.shp” shows that it is represented by lines. so it’s worth the effort.shp” and “PA_major_roads.shp. the counties in Pennsylvania. Vector data are represented with icons that show whether they are made up of points. The file named “philadelphia_pa_ne. the text file is a description of the map layer.tif” has a different sort of icon that indicates that it is raster data. Starting with version 9.shp” layer icon indicates that it is made up of polygons. In the screen capture to the right.shp” so it cannot be viewed by ArcView. The icon for “hospitals_pa. a format of vector data specific to ESRI (but often use-able in other GIS software).shp” are all shapefiles.2.shp” shows that it is made up of points.x.dbf or comma-delimited text.
2 1 In ArcCatalog these various files will appear as a single shapefile. highlight the shapefile name. 2 . for example). If you try to do any of these procedures using My Computer. or renaming shapefiles.Launching ArcCatalog Shapefiles. To create thumbnails for shapefiles and images (you cannot create thumbnails for tables). pasting. indicating that the layer no longer has integrity. Each of these will have the same name but a different extension. are made up of three or more separate files. Click on the “contents” tab in order to view thumbnails.shx.dbf. you would see all of the files listed with extensions such as . including maps and layers created in ArcMap.shp. or rename all of the pieces that make up the shapefile. In other words. ArcCatalog will display a thumbnail image of your data when the “contents” tab is active. ArcCatalog allows you to view your data as ArcGIS sees it. paste. If you viewed them outside of ArcCatalog (in My Computer. ArcGIS will no longer recognize it as a single map layer. or rename even one. . If you fail to copy. This makes ArcCatalog an ideal place for copying. The icon for the incomplete layer may have a question mark. and click on the “Create Thumbnail” button. 3 6 H I l l I E R | U S I n G A R c V I E w 9 . Creating Thumbnails For some files. the dominant format for vector data in ArcView. you will have to copy. . paste. click the “preview” tab.
You can also view images here (ArcCatalog may ask you if you want to build pyramids in order to display these more quickly. which is probably a good idea). You can also access these functions in ArcMap. on ArcMap).” you can see how your data looks as a map. freeze/unfreeze column. and statistics (the statistics option is only available for numeric fields). lines. Switch the preview drop-down to “table” in order to view the attributes associated with your geographic features. When the preview drop-down menu at the bottom of the window on the right is set to “geography. You will only be able to see the basic points.Previewing Files By making the “preview” tab active. delete field. you can look more carefully at files. Click on the “options” button to add a new field or export the table. You can zoom in and out and identify the basic attributes of the features in your map (these tools will be described in detail in the next section. Right clicking on a column heading allows you to access a number of other functions such as sort. I n T R o d U c T I o n 7 . or polygon outlines—you cannot make thematic maps showing different data values across your map—but this preview feature allows you to look quickly at your data.
Viewing and Updating Metadata ArcCatalog also allows you to update and store metadata. These different data formats are described in detail in the section entitled “Calculating New Values. the length of the field will appear below. or the documentation. but you can change this from the stylesheet dropdown menu. you can see what datum and projection have been defined (if any). When you click on a column name. Click on the “edit metadata” button in order to add or edit 8 H I l l I E R | U S I n G A R c V I E w 9 .” but generally speaking. 2 . create/update metadata. Metadata are essentially data about your data.Checking Properties Double click on the file name to bring up the shapefile or table properties (or by highlighting the file name and choosing “properties” from the File menu). view metadata properties. This includes information about who created the data. From the Indexes tab. ArcCatalog offers several different stylesheets that define the types of information that can be included in the metadata documentation. querying. you can create attribute or spatial indexes in order to increase the speed of searching. and drawing data. you can identify the data format for each of the columns in your table. With the fields tab active. and whether there are restrictions on its use. how they created it and for what purpose. the way values are formatted in your table will dictate what kinds of functions and representations are possible. The default is ESRI’s stylesheet. import. Click on the “metadata” to view available information. and export metadata. From the XY Coordinate System tab. The buttons to the right of this dropdown menu allow you to (in order) edit metadata. but it is important to get in the habit of checking and updating metadata. Not all data you acquire will come with metadata.
” I n T R o d U c T I o n 9 . but fill in as much as you can. and geographic level). This will be described in the section “Creating New Shapefiles. You can create new shapefiles in ArcCatalog. You will probably not be able to fill in all of the requested (“required”) fields. and data quality (are there known problems?). making it possible to locate files based on name. limits on access (who can use the data?). and date. geographic location. ArcCatalog also has extensive search capabilities. Most important are a description of the data (including the date. data values (is there a data dictionary that explains the meaning of values?). Other ArcCatalog Functions These are the basic functions in ArcCatalog—organizing and previewing data and working with metadata. location on your computer.your metadata. contact information (when and from whom did you acquire the data?). spatial extent.
you will be asked if you want to open an empty map. Otherwise. The default view will use the same icons that appear in ArcCatalog to represent your layers. From the file menu. then ArcMap. Highlight the layers you want (hold the control key down to select multiple layers).” Adding Data Unless you open an ArcView . You can prevent this dialog from displaying again by putting a check mark in the “do not show this dialog again” box. You can add and edit data. go to “Add data” or click on the “Add data” button (yellow square with large black + sign) on the Standard toolbar. then click “Add. and create map layouts for printing. 2 . You might also consider creating a desktop icon for ArcMap if you plan to use it regularly. choose “open an empty map.mxd file that someone else created. you will need to add data to get started. When ArcMap opens. click on the “Launch ArcMap” button. Starting ArcMap You can launch ArcMap in several ways. use a template.IntroductIon to arcMap ArcMap is where you create maps and access most of the ArcGIS functionality. If you are in ArcCatalog. you can also click on the “Thumbnails” button on the far right to see the thumbnail image of each map layer. query and symbolize map layers. Alternatively. Navigate to the folder where you have your map layers. then ArcGIS. 10 H I l l I E R | U S I n G A R c V I E w 9 . go to the start menu. or open an existing map.” If you created thumbnails for your map layers in ArcCatalog.
Connecting to Folder When you open ArcCatalog. hold down. so don’t be surprised if ArcMap looks slightly different each time you open it. the window on the right that shows your map is the map display. You can delete paths using the “Disconnect from folder” button (globe with yellow X). You can close the table of contents by clicking on the “x.” To bring your table of contents back. The window on the left that lists your map layers is the table of contents.” Your folder should now be listed under “Catalog” next to a icon. Resize it by holding your cursor over the right edge until your cursor changes to a two-headed arrow. From the file menu. then left-click and drag the edge to resize this window. Navigate until you find the folder with your data and click “OK. To move one of your toolbars. One note of caution: You do not need to do this repeatedly. left click on the end (top or left). Once you have established a connection to your folder. then Table of Contents. “Connect to folder” allows you to make a direct connection to the place on your computer where your GIS data are stored. Customizing the Interface ArcMap is made up of many different windows and (dock-able) toolbars that you can resize and move around. go to the Window menu. a list of all the folders and sub-folders on your computer will be displayed on the left in the catalog tree. I n T R o d U c T I o n 11 . your path options will become unmanageable. If you create a new connection to the folder each time you use ArcGIS. you will not need to do it again unless you change computers. go to “Connect Folder…” or click on the “Connect to Folder” button (yellow arrow against a globe). and move to a new location.
2 . the table of contents will only list data that can be drawn as a map layer. you will want the “display” tab to be active. go to the View menu. then “toolbars” or double-click on an empty gray part of the screen. the table of contents shows the path indicating where the data—including tables—are stored. Layers are drawn in the map display in the order in which they are shown in the table of contents. Click on the “commands” button to see your options. 12 H I l l I E R | U S I n G A R c V I E w 9 . You can add new buttons to existing toolbars from the “customize” option.” Working with the Table of Contents The table of contents has three tabs (at the bottom): display. so you will not see your tables listed. To add or remove a toolbar. One especially helpful button allows you to zoom continuously.You can move a toolbar by double-clicking on it to the left of the buttons (where there is a sort of handle at the edge). You can only re-order layers from the display tab.” then left click on the “Continuous Pan and Zoom” button on the right and drag it to your tools toolbar (the toolbar with the outline of a hand and an image of a globe in the middle) and release (see image on previous page). You can “dock” it by moving it over any of the gray areas on the screen. The selection tab allows you to choose which layers you want to be “selectable. Map layers listed at the top will draw on top. then move the layer. source. Turn on and off a layer by checking and unchecking the box next to it. You can also add new buttons and tools by importing scripts. Scroll down to the category on the left called “pan/zoom. That process is explained in a later section called “Working with scripts.” Most of the time. and selection. When the display tab is active. When the source tab is active. To move a layer. Anything with a check mark next to it will be displayed. left click and hold the mouse button down.
left or right without changing the extent (the degree to which you are zoomed in or out). The continuous zoom tool gives you the greatest amount of control. you will zoom in or out a fixed amount. Using the non-continuous zoom tools. The previous extent buttons allow you to return to the extent you had before zooming in or out. down. you can click on your map to zoom in or out at a fixed amount or to draw a box around the area that you want to see in more or less detail. Click on the continuous zoom tool. The fixed zoom in/fixed zoom out tools give you the least control but also may keep you from zooming in or out too much and losing your map. Each time you click. The next extent button allows you to jump forward an extent (after you have used the previous extent button).Navigating a Map There are several tools available for zooming in and out of your map. The full extent button will zoom in or out so that all of your active (checked) map layers can be viewed. You can also zoom in to a single layer by right clicking on the layer in the table of contents and choosing “zoom to layer.” The pan tool works like the continuous zoom tool when you right click on it. hold down the mouse button. The new map will be drawn so that the area you drew the box around is in the middle of the map display. this becomes a tool for panning (moving map around without changing the extent). but you have to add this by customizing your toolbar (see “Customizing the Interface” above). This is very helpful when you zoom in or out too much and can’t see your map layers. Think of the pan tool as a sticky hand you set down on a piece of paper. I n T R o d U c T I o n 13 . You use it to move your map up. then left click on your map. and move your mouse away from you to zoom in and toward you to zoom out. If you right click and hold down.
lines. An “identify results” box will display all of the information known about that feature. 14 H I l l I E R | U S I n G A R c V I E w 9 . You can change this using the dropdown menu at the top of the identify pop-up box. This is part of what makes GIS unique. The default in ArcMap is to display information only about the topmost layer. Notice the layers dropdown menu. that it can connect attributes of a location to that location.Identifying Attributes of Features The points. click on a map feature in the map display. 2 . Using the identify (“i”) tool. You can access this information in several different ways. and polygons that make up vector map layers are all map features that have attributes stored in a table.
Put a check mark in the “Display Map Tips” box. To change the primary data field. make the Fields tab active and choose a field from the “primary display field” dropdown menu. make the Display tab active. double click on your shapefile name in the table of contents and. You can only see one attribute at a time (unlike the identify tool. To turn on map tips. from the Layer Properties.Showing Map Tips Map tips are small text boxes that appear when you hold the cursor over a map feature. which allows you to see all the attributes know for that map feature). I n T R o d U c T I o n 15 . but using map tips is much simpler and allows you to get a quick idea of the attributes.
By default. This way. It is also possible to use different selection colors for each layer. either by clicking on a particular map feature or by drawing a box around the feature(s) of interest.” Choose the selection tab and then select the last radio button.” This will only change the selection color for this map layer. click on the “selected” button at the bottom of the table. Right click on the map layer that contains the feature(s) that you wish to investigate and go to “open attribute table.Selecting Features You can also use the select features tool to identify attributes. You can change the selection color from “options…” in the Selection menu. 2 . In order to view just the selected feature(s). all layers will be selectable. 16 H I l l I E R | U S I n G A R c V I E w 9 . You can also highlight a feature on the map by clicking on a row in the table. The “section” tab in the table of contents allows you to identify the layers you wish to select. Double click on a map layer.” This table includes all the attributes of all the features in that layer. you can find a specific place (such as Cyprus) on your map. “Show selected features with this color. The selected features should become highlighted with a blue outline. or right click and go to “properties.
I n T R o d U c T I o n 17 .
fill color. Some of the simplest options involve the choice of color. you can choose from a variety of patterns. These are considered “thematic” maps and they will be discussed in the sections on displaying points. 2 . and polygons. click on the map symbol in the table of contents. you can choose a different marker from the default (which is a circle with a black outline). and angle using the options on the right of the window. lines. You can find many more symbols by clicking on “more symbols. To make changes. For example.Changing Map Symbols ArcMap has many options for changing the way your data are displayed. When you choose a new marker. You can also symbolize your layers based on different values for each map feature. you might use different size points to represent different cities around the world according to their population or use differ color markers to represent different types of hospitals. The “reset” button will undo any changes you have made to the symbol since opening the symbol selector window. expressways. you have choices about the fill pattern. For points. and railroads. size. The symbol selector window that opens will look different depending upon the type of layer: point. thicknesses. or polygon. fill pattern. There are industry standards for things like highways. the default size jumps from 4 point (quite small) to 18 point (quite large). The properties button will give you additional options (and often too many options) but may be helpful in fine-tuning the crosshatch and ordered stipple patterns. 18 H I l l I E R | U S I n G A R c V I E w 9 . and shape (for point data). and outline color.” You can change the color. and colors. For polygons. For lines. line.
The . go to the File menu. Navigating to the file in its new location and clicking “add” will solve the problem. It also means that map documents can be difficult to transfer from one computer to another.mxd) When you open ArcMap. You do this by going to the File menu and choosing save. If you specify that you want to use relative paths. Instead. If you do move one Using Relative Paths One way to minimize problems when you move files that are part of an ArcMap document is to use relative paths. you will probably want to save an ArcMap document. or Internet) and the formatting changes you made. If you click on the grayed out check mark beside the layer name.mxd file on a thumb drive to open on a different computer without running into problems. To set relative paths. it includes information about the location of those files on your computer (or network. you will not be able to find or open your work. of the files used in your map document. If you will need to return to your work once you start symbolizing your map layers and designing a layout for printing.” I n T R o d U c T I o n 19 . “Store relative path names.” Choose the radio button. and the layout. ArcMap will bring up a dialog asking where you moved the file. ArcGIS works differently from most software. symbology. It is best to only save an ArcMap document when you have spent a significant amount of time. that layer will be shown with a ! next to it and will not draw when you open your map document. Most of the time when you are learning to use ArcView. you are prompted to specify whether you wish to open an existing map document or create a new one. ArcView will be able to find the pieces of your ArcMap document as long as you keep the files used in the . including the list of data you have added and the changes you have made to layer properties. Saving ArcMap Documents An ArcMap document is made up of all the map layers you have added and all of the functions you have applied to them. you can create a new ArcMap document.mxd file does NOT save all of the data you included in your map. This means that you cannot move the data files you’ve included in a map document or just put your .mxd ArcMap document in the same folder (so you can move that folder from one drive to another as long as you don’t move the individual shapefiles out of the folder). so if you do not take care in naming and saving your files. This file will save all of the work you have done. choose “map properties” and click the button “Data Source Options.ManagIng & SavIng data Many of the frustrations of new GIS users relate to saving files. Map Documents (.
mxd file. projection. in another map document.shp Phila_bgroups_2000_stateplane.shp and then give the file a new name.). Keep all map documents. map layers. Otherwise you will end up with files called “Export_Output. ArcGIS can also work with files that have spaces in their name (such as Phila tracts. but really long names can be difficult to work with. will create problems.lyr). Even though it will require more storage space. You may create multiple versions of the same shapefile that are only slightly different. You need to develop your own naming convention that makes sense to you.shp). you will also be creating new tables and shapefiles. As you work with ArcView. Saving and Storing Files The most important thing in storing files for ArcMap is to think through a system BEFORE you start.shp” and other unhelpful things like that. and tables in that directory. This file will store all the formatting changes you have made to the layer. Moving your original data.shp NYC_tracts_1990_UTM.lyr file to another computer. As with the . Consider creating a new directory for each new mapping project. 20 H I l l I E R | U S I n G A R c V I E w 9 . in each project folder where you will be using it. attributes. 2 . the . or moving the . so you can avoid moving files and disabling your map documents and layers. This is particularly helpful if you want to use the same layer. geographic level. etc. but this can create problems (especially with attribute names) so it is best to avoid by using underscores (_).ArcGIS can work with file names that are more than 8 characters. you may want to keep separate copies of the same map layer. For example: Click on the folder icon to show ArcView exactly where you want the new file Phila_tracts_2000_UTM. you can save an individual map layer (. you will be given an opportunity to give it a name and specify a location with a dialogue box like this: Saving Map Layers In addition to saving the entire workspace with a map document. Whenever ArcView is creating a new file. with the same symbology. so your naming convention should reflect those differences (in year.lyr file only includes information about the formatting and the path to the original data (generally a shapefile). Naming Files Naming your files in a clear and consistent manner will make working with ArcMap much easier. such as a streets layer.shp Phila_tracts_1990_UTM.
then you know the data are in a geographic coordinate system. If there is no projection information.prj file. the image appears to be sagging to the east.This layer does not have a . For example. you can map the data to try to determine its coordinate system. If the map units displayed in the gray bar below your map are in degrees. so there is no projection information listed under the “source” tab. You may also recognize this because your maps look distorted. and minutes. I n T R o d U c T I o n 21 .” Map layers downloaded from the US Census Bureau are generally in this format. Map layers in geographic coordinate systems are sometimes described as “unprojected. when Philadelphia map layers are in a geographic coordinate system. seconds.
Geographic data can be categorized as vector or raster. You must specify which worksheet you wish to add.xls file to see the names of the worsheets. 22 H I l l I E R | U S I n G A R c V I E w 9 .2 can work with more different data formats than previous versions of ArcGIS. double-click on the name of the . This manual deals primarily with vector data. You do not need to geocode if your table already includes XY coordinates. data might be collected usinga GPS device or a data vendor might sell the names and addresses of supermarkets and include XY coordinates for mapping. Unlike previous versions.data forMatS ArcGIS can work with many different types of data. ArcView 9. ArcView 9. SAS. Converting lists of addresses to points on a map usually involves a process called geocoding and is explained elsewhere. Simply add the table to ArcMap. When you add data.3 can work with Excel files. This is where you store attribute data. If you know the projection used to collect or create the data. and dbase files. Tabular data Tabular data includes things like comma delimited or fixed width text files.” Geographic data The tabular data you use in ArcGIS can be used in other programs like Excel. SPSS. right click on the table. Highlight a worksheet and click “add. but the geographic data you use can only be used in GIS programs. 2 . only some of which are described in this section. so they cannot be mapped until they are linked to a map layer. and STATA. ACCESS files. which includes any information you have about a location. click on the Edit button. and go to “Display XY Data…” From the Display XY Data window. Excel worksheets. choose the field that contains the X (longitude) and Y (latitude) coordinates. Geographic data store information about location so that they can be represented as map layers. Adding XY Data Some tabular data include XY coordinates. For example. Tabular data generally do not include location data.
Vector data use points.sbx . The shapefile stores information about the shape of the map features. As with other formats of geographic data. When a shapefile is added as a theme to a view. . such as temperature and elevation. . or polygon) . Topologic formats (like coverages used in ArcInfo) contain detailed information about the relationships among features in the same map layer.the file that stores the feature geometry (point. shapefiles link information about the location and shape of the map features to their attributes. In creating the shapefile format. ESRI intentionally created something that is simpler than existing topologic formats for desktop (rather than professional) GIS users. ESRI created the shapefile format in order to represent vector GIS data in a simpler format than their coverage format used in ArcInfo.sbn and . This will only exist for shape files with defined projections. or polygon. or create an index on a theme’s shape field. These two files may not exist until you perform theme on theme selection. This allows for a variety of operations to ensure the integrity of lines and polygons and to carefully edit and create new geographic features.dbf . such as parcels. you will only see one file. Using this information. spatial join. Topology On of the biggest complaints about the shapefile format is that it does not contain information about topology. When you look at your shapefiles through ArcMap or ArcCatalog.the file that stores the index of the feature geometry .pjr – the file that stores information about the projection. describing them in the “shape” field of the attribute table as point. and polygons to represent map features. Shapefiles are made up of three or more files that need to be stored in the same directory in order for ArcView to recognize them as shapefiles. ArcView can calculate area and perimeter for polygon features. I n T R o d U c T I o n 23 . Vector GIS is not as good for representing things that vary continuously over space. line. this file is displayed as a feature table. but if you look at them directly on your hard drive or thumb drive.the files that store the spatial index of the features. It also stores information about the real world location of each vertex that makes up the map features.shx . lines.shp .Shapefiles Shapefiles are the most common format for vector data in ArcView. streets.the dBASE file that stores the attribute information of features. Vector GIS is excellent for representing discrete objects. but geographic files from other GIS programs must be converted to shapefiles before ArcView can read them. line. and administrative boundaries. Other GIS programs will allow you to use shapefiles. you will see multiple files with the following extensions: .
you will often be prompted to decide whether you wish to “build pyramids.” Generally you want to say “yes” because this will make it easier to work with the image in ArcMap. . The images you import may be scanned paper maps. So why would you add an image to ArcMap in the first place? Because images like aerial photographs and scanned historical maps can be transformed into map layers through a process called georectifying. Images are like tables in that they may contain information about a particular location. to represent spatially continuous data. You will also receive a message that ArcMap is unable to draw the image as a map layer because it is missing information about location. You can view raster layers in ArcMap without any additional extensions. When raster layers have the same size cells. so the data can be mapped. CGM. ArcCatalog recognizes GRIDs and other image formats (including BMP JPEG. subtracted. They look like regular images. JPEG. then click “add” (if you double click. divided and queried using map algebra (a system developed by Dana Tomlin). JPEG. but each pixel is assigned real world coordinates and an attribute value (such as precipitation level or elevation). their values can be added. and PNG. allowing for very fine or course raster surfaces. The user defines the cell size. Raster map layers Raster data use grids made up of regular cells. . PCX. multiplied. When you add a large image to ArcMap. You can also export finished maps in ArcMap in a number of formats: EMP BMP EPS. using the “add data. ArcMap saves raster layers in its GRID format. you can see the individual square cells when you zoom in. Even when the cell size is very small. You can add raster data to ArcMap just as you do vector data. TIFF. 24 H I l l I E R | U S I n G A R c V I E w 9 . ArcMap can import a wide range of file types. or other pictures or photos that you “hot link” to your map features. 2 .Images ArcGIS allows you to import and export many different types of images. . aerial photos. but you need the Spatial Analyst extension to analyze or create new raster layers. PDF. TIFF) as raster layers.” Be sure to highlight the layer you want. or pixels. but they do not store location information so they cannot be mapped. you will see the individual bands that make up your raster lay).
shapefiles. Geodatabases are more complicated than shapefiles and a license for ArcEditor (not just ArcView) is required to edit geodatabases. Shapefiles are generally sufficient for individual projects. I n T R o d U c T I o n 25 .Geodatabases ESRI has moved toward a new geographic data model called a geodatabase that used Microsoft ACCESS files to store multiple tables. and raster images. but geodatabases are more appropriate for work environments where multiple people are accessing information or when advanced editing is required.
particularly if you inherit data or download it from the Internet. You may not always know the coordinate system used. But knowing and setting projections properly is also important for getting your may layers to draw together. Recognizing the Coordinate System Map layers can be drawn according to a geographic coordinate system (unprojected) or projected coordinate system. When you are looking at a relatively small area. and some of ArcView’s tools to work. Geographic coordinate systems indicate location using longitude and latitude based on a sphere (or spheroid) while projected coordinate systems use X and Y based on a plane. All projection systems distort geography in some way—either by distorting area. click on the “…” button to the right of “Spatial Reference. even within the same parts of the world. As long as computer screens and printed maps are flat. There are dozens of different projection systems in use because different systems work best in different parts of the world and. ellipsoid) earth is viewed as a flat map. GIS users have different priorities and needs. This layer has a . Alternatively. so there is projection information listed under the “source” tab. such as a single city. the map layer will include a .2 | spatIal data workIng wIth projectIonS Projections manage the distortion that is inevitable when a spherical (okay.” You can access the metadata through ArcCatalog. click inside the “shape” field and 26 H I l l I E R | U S I n G A R c V I E w 9 . shape. or scale. distance. you can click on the “fields” tab of the layer properties from ArcCatalog. 2 . there is relatively little distortion because the curve of the earth is slight.prj file. You can look at the information in the .proj file which contains information about the coordinate system or the metadata will explain.prj file—the detailed spatial reference information—by clicking on the “general” tab of the layer properties from ArcMap. If you are lucky. projected coordinate systems will be more appropriate for working with GIS data. distance units to make sense. direction.
Click on “data management tools” and then “projections and transformations.” and “NAD 1983 Datum. In most cases. you will be able to find it in the dropdown menu. Then you can choose the coordinate system using the button.” then click “okay. you must create a .proj file associated with your map layer and you can look at the detailed spatial reference information. then you can “project” the map layer using the projection of your choice. Before you define a layer as unprojected.proj file “defining” the map layer as unprojected.” You should not notice a difference in how the map layer is drawn as a result of defining the coordinate system.” Defining projections Defining a projection registers your map layer with a known projection. there is now a . ArcView will refer to it as “assumed geographic.” “North America. But as a result of defining it. First you will be asked to choose a data layer.Working with “Unprojected” Layers In most cases. There are two steps involved in this process. Click the “select” button on the Spatial Reference Properties. Otherwise you will need to click on the folder icon to locate your map layer. It involves reporting to ArcView the nature of the data that you have. To “define” the coordinate system for your unprojected map layer.” 2 | S P A T I A l d A T A 27 . If you added the relevant map layer to ArcMap. First. You can access the tools for doing this by clicking on the ArcToolbox icon inside ArcMap. you can choose “Geographic Coordinate Systems. you will want to convert unprojected map layers—those with a geographic coordinate system—to projected map layers. not changing that data. click on the “Define Projection” wizard.
UTM coordinates will be in meters and look like 486850. area. 28 Working with Projected Map Layers Sometimes the map layers you acquire will already be projected but won’t carry a . consider UTM zone 18N. ArcView will add “_Project” to the original name. The best thing to do in this situation is to look at the original source for information about the projection system. You are best off choosing whatever projection system is most commonly used. For relatively small areas like Philadelphia. either on a website.98. You can only do this if you have defined (registered) the existing projection. If you are projecting a shapefile. then choose “Projected Coordinate Systems. they are probably projected.” If you are projecting a raster image.” In order to map your newly projected layer. use the “Project” wizard listed under “Features. create a new ArcMap document and add the new (projected) layer. Click on the button to the right of “Output Coordinate System” to choose your projection.” ArcView will indicate that there is a “Datum conflict between map and output. Click on the “select” button on the Spatial Reference Properties. use the “project” wizard listed under “raster. You can project map layers that are unprojected (geographic coordinate system) or change the projection on layers that already have a projection system. As you work with a particular projection system. For the Philadelphia MSA. you will be asked to specify the map layer.19. 246268. direction. You may wish to give your layer a different name. click “okay. You may recognize the projection by the units showing in the gray bar below the map. you are asked to name the new layer that will be created. You should notice a change in the coordinates that show in the bottom right of the map.Projecting shapefiles Projecting a shapefile changes the projection system. click on the “Project” wizard. State Plane coordinates for Philadelphia are generally in feet and look like 2691607. 4430095. map the data in order to guess the projection.72. After making your selection. If they are not in longitude and latitude. If these approaches all fail to reveal the projection.proj file so you won’t know the projection. For example. By default. H I l l I E R | U S I n G A R c V I E w 9 . in metadata that came with the file. that is State Plane 1983 (feet) Pennsylvania South. In Philadelphia. In order to project the map layer. distance. the differences in projection systems (the distortion in shape. and scale) are minimal.” As with the “define” wizard.78. 2 . you will come to recognize the map units and range of coordinate values. Next. because you will be changing the original layer. or by calling the person who created the data.” Now you need to choose your projection.
and make the Coordinate System tab active.” go to Properties. or geoprocessing functions.proj file. Alternatively. you can choose a coordinate system (State Plane 1983 is in the “Projected Coordinate Systems” folder inside the “Predefined” folder). You will need to select the projection from the “Projected Coordinate Systems.” If a map layer is already projected AND defined. but you may not be able to use ArcView’s “on the fly” projection capabilities. although in most cases you will probably have just one). you can use the “Define Projection” wizard in the ArcToolbox. you can change the projection using the same tool. measurement tools. If you know the projection. All of the map layers listed under the Layers icon in your table of contents are in the same data frame (you can have multiple data frames in the same map document. Defining Projection for Data Frame Ideally. Right click on the word “Layer. spatial join. you can set the projection for your Data Frame for your 2 | S P A T I A l d A T A 29 . map document. You will need to add the reprojected map layer to a new ArcMap document in order to see the results. Data that are projected but missing spatial reference information will look fine when they are drawn.When you add a shapefile to ArcMap that the software recognizes as being projected but has no . From here. you will know and will specify the projection of each of your map layers. ArcMap will usually warn you that spatial reference information is missing.
Change the projection using the “project” wizard. (c) that matches your other map layers. If it does not include the word “assumed” or “undefined” it is defined. you will likely get a message about “inconsistent” spatial reference information. Be sure to choose something from the Projected Coordinates folder. Then determine the projection you want and set it using the “project” wizard. Is it projected? No. Choose a map projection that (a) reflects local standdards. Look in the “source” tab in the layer properties to see if a coordinate system (either geographic or projected)is listed. Make your best guess of the projection and define the map layer using the “define” wizard. Also. The coordinates in the bottom right of the map are your best clue as to the projection. 2 . Is the layer defined? A layer is not defined if the “source” tab in the layer properties says “undefined” or “assumed. As long as the layer is defined. it is NOT defined. try another projection. Yes.” Also look for pop-up message when you add a layer to ArcMap that says spatial reference information is missing. You will know that you chose the right projection (or close enough) if you can get your layers to draw together. it is defined. Add map layer to new ArcMap document. Determine the projection you want and set it using the “project” wizard. The coordinates on the bottom right of your map may also have “unknown” units. Is it defined correctly? If a map layer is defined incorrectly. Yes. not defined correctly Yes. 30 H I l l I E R | U S I n G A R c V I E w 9 . (c) that matches your other map layers. look for “GCS assumed” in the source tab. Also. it is not projected YES NO Re-define the map layer using the “define” wizard Do nothing unless you want to change the projection. The map layers should draw together. No. it doesn’t matter what projection system is used. Define the layer as geographic NAD 1983 using the “define” wizard. (b) that is designed for that geographic area. defined correctly. If your map layers do not draw together. it is projected No. you may want to use the same projection for all of them. (b) that is designed for that geographic area. look for inconsistency between the coordinates on the bottom right of the map and the defined coordinate system in the source tab.A layer is defined if ArcView knows whether and how it is projected. If you are building a project-specific GIS with many layers. Choose a map projection that (a) reflects local standdards.prj file with the same name as the map layer in the same directory as the other pieces of the shapefile if the layer is defined. Is it projected? Your data are probably not projected if your map is sagging and/or has lat-long coordinates. There will also be a .
Troubleshooting with Projections If you are unable to draw your map layers together or if your distance units do not make sense.tif and 300 dpi or better. the process assigns X and Y coordinates to points on your digital map image. Create a raster image Scan your paper map. the more mixed up your projections get. Try starting over with your original files (be sure to keep a copy of the originals before messing around with the projection). you may want to show your shapefiles to someone with more GIS experience. and scaling your map so that you can view it as a map layer along with your shapefiles. Be sure that you can identify a few places on your scanned maps on this shapefile (such as a landmark or street intersection). The simplest form of this. ArcMap can handle pretty big files. add a shapefile that covers the same geographic area. This might be a street centerline file. go with . The higher resolution. If you have a choice. is explained below. the better. rotating. 2 | S P A T I A l d A T A 31 . you are likely experiencing a problem with projections. you will not be able to use on-screen georectifying. and it can work with lots of file types (.bmp). shifting. Add reference layers (shapefiles) Before you add your scanned image. . city boundaries. . or something similar.tif. using onscreen tools. georectIfyIng IMageS Georefectifying allows you to convert a paper map into a GIS map layer.jpg. and frequently the more you try to fix the problem. Essentially. If you are not able to figure out the problem. Otherwise. It is easy to get confused while using the “Define Projection” and “Project” wizards.
” Depending upon the size of your image. The name of your image should now appear in the table of contents. 32 H I l l I E R | U S I n G A R c V I E w 9 . 2 . Click “OK. choose “fit to display. a dialogue box will ask you if you’d like to add pyramids. so it shouldn’t contain any spatial information. From the georeferencing menu.” From the view menu. but you will not see your image drawn with your shapefile. At this point. using the button or from the file menu. rather than your image. To see your image. Right click on the shapefile and choose “zoom to layer. then georeference. you’ll need to switch back so that you can see your shapefile. your image is in “pixel space” since there is no coordinate information. If your scanned map is upside down. choose toolbars.” Don’t worry if you get a warning message that your image lacks projection information. At this point. use the “Flip or Rotate” tools.Add map image Add your image to ArcMap just as you would a shapefile or table. right click on the name in the table of contents and choose “zoom to layer. your scanned map is just an image. choose “add layer.” In order to start georectifying.” Now your reference layer(s) should draw on top of your map image in the view map window.
then click on the shapefile in the corresponding spot. Be sure to click on your scanned map first. You may find it helpful to use the magnifier window (from the window menu. Your image should shift closer to your shapefile. then the shapefile. Continue to add control points as long as doing so improves the alignment. If it gets further away. after before 2 | S P A T I A l d A T A 33 . your image should be more or less lined up with your shapefile. choose “magnifier”) so that you can see your map details without zooming in. you probably reversed the order.Add control points Click the “add control points” button. Create your first control point on your image by clicking once on your scanned map. After doing this a few times. Continue to add control points.
choose “rectify” from the georeferencing menu. The control points are listed in the order that you created them. however. If the image gets further and further away from the shapefile. hightlight it and click the delete (X) button. But be sure to look at how these transformations distort your map. 2 . You can also delete a single control point using the “view links” button. Rectify Image In order to permanently save the transformation. From the georeferencing menu on the georeferencing toolbar. so go to “add data” and take a look at your new rectified map before you delete your image. go to “delete control points” and “reset transformation. you can perform a third order transformation. try starting over. so the most recent control point will be listed last. ArcMap will create a new image (rather than changing your original data). If the resolution of the rectified map is much worse than your original scanned map. The original map you scanned may have been created using a different projection system or included distortions and the map may have been further distorted or damaged over time. Transformations If you have six or more control points. try rectifying it again and specifying a smaller cell size. You may be better off with the first-order transformation. your map image will not line up perfectly with the shapefile and you should not expect it to. To delete one. 34 H I l l I E R | U S I n G A R c V I E w 9 . if you have twelve or more control points. ArcView will not automatically add your new rectified map in. you can perform a second order. Check the ArcMap Desktop Help if you want information about choosing a resampling type.In most situations.” then choose “fit to display” again.
linking your attribute data to your spatial data. Changing the symbol ArcView has numerous palettes of symbols used in various industries. In the box on the left side. such as conservation and policing. click on the “properties” button. For example. or color of the symbol by clicking on it. the symbol for a school bears little resemblance to a large urban school.”) and click on the “Symbology” tab. 3 | M A k I n G M A P S 35 . Keep in mind that just because there are near infinite combinations that the simplest symbols (such as block dots) may be the most effective. and color symbol. shape. These specialized symbols are effective when used carefully with an audience that will recognize them as industry standards. ArcMap offers a wide range of colors and symbols for representing your point data. The symbols included in the default palette may not be ideal for your map.3 | MakIng Maps SyMbolIzIng poIntS The real strength of a GIS is in allowing you to use different symbols to represent different values. shape. This is how ArcMap will display your point shapefiles when they are first added to a map document or when you create them through geocoding or adding XY data. The “civic” palette contains a number of choices for schools. To view additional pallete. Open the layer properties (double click on the shapefile name or right click and go to “Properties. but as long as “Single symbol” is selected. “single symbol” will be highlighted. Single Symbol The default in ArcMap is to represent all points with the same size. You can change the size. all of your points will appear the same.
For example. a hospital might be managed by a non-profit. or for-profit entitity. in reality.” Use the black arrows on the far right to move values up and down (the order here will be the order your values appear in the legend on your map). etc. This can work well for small files (10 or fewer points) but can quickly be overwhelming for larger files. such as the population of a city or air emissions. however. These are. Quantities. federal government. In addition to different colors. right click on it and choose “Remove Value(s).In most cases. You don’t need the symbol of a needle to represent drug crimes. person. use different sizes and symbols. Choose the field with the values you wish to use to represent your points. they are just different. after all. Quantities Categorical variables correspond to categories and are generally represented using text variables (or numbers used as codes for individual categories). This implies that one category is more or less than another when. state government. or selected symbols (hold down the shift key to select two or more) by right clicking. you are better off sticking with the default symbols. You can make changes to all of the symbols. church. To remove a value. building. then click the “Add All Values” button. The unique values option listed under “categories” in the symbology tab allows you to use a different symbol for each of the points in a shapefile based on a categorical variable. Don’t use a graduated color ramp with light to dark shades of the same color. Categories Categorical variables classify data into unique categories so that each observation (event. You can change the individual symbols by clicking on them. are continuous and must be presented with numbers.) fits in only one category. Graduated symbols and proportional 36 H I l l I E R | U S I n G A R c V I E w 9 . Choose colors that communicate that these are separate categories. symbols and you will be able to describe the symbol in the legend. ArcMap will list a symbol for “<all other values>” that you can remove by taking away the check mark. 2 . Resist the temptation to be too literal.
For example. click on “Quantities” and then “Graduated symbols. To change this. 3 | M A k I n G M A P S 37 . The default is five categories. a hospital that has 100 beds would be represented with a symbol that is twice as large as a hospital with 50 beds.” which uses Jenks optimization to identify grouping of values that minimize within group differences. but the size of the symbol reflects the relative size of the quantity. Use the “classes” dropdown menu to change the number of categories.symbols are the best choices to show different quantitative values for points. With the symbology tab active.” From the “Values:” dropdown menu. Alternatively. you can change values manually on the previous screen by clicking on them (you will only be able to change the ending value). select the field with the values you wish to use. so five value ranges represented by different size dots should appear below. Graduated symbols allow you to have different size symbols to represent different attribute values. There are many ways to break up value ranges into categories. The default is “Natural Breaks. click on the “Classify” button and use the Method dropdown menu to choose a different classification system. Proportional symbols are similar to graduated symbols. Proportional symbols are preferable except in situations where the symbols become too large and obscure other points. You can also adjust the cutoff points by moving the blue vertical lines in the histogram below that show the frequency of values.
normalize the total number of households receiving public assistance by the total number of households. From “Layer Properties. Do not use the “<PERCENT OF TOTAL>” option to create a rate. you will need to select the variable from your attribute table that serves as an appropriate denominator. On the left side of the screen. Choropleth maps are generally better at representing rates (such as percent registered voters) rather than counts (such as total voters).SyMbolIzIng polygonS (area data) The options for symbolizing polygons (such as census tracts) are basically the same as the options for symbolizing points. In order to use this appropriately.” Choose the field with the values you wish to use. Use the “Classes” dropdown menu and the options in “Classify” to change the number of categories or method for breaking values into categories. For example. You can transform count data into rate data using the “Normalization” dropdown menu in the “graduate color” option. 38 H I l l I E R | U S I n G A R c V I E w 9 .” click on the symbology tab. click on “Quantities” and “Graduated Color. but the attribute data that you have for polygons will often be different so you will utilize the same options in different ways. Graduated Color You can use different colors—or different shades of the same color—to represent different continuous variables (such as household income or median age) to create choropleth maps. 2 . in order to show the percent of households receiving public assistance.
saturation(S). To do so.Styles. Select a color for Color 1 (the beginning of the color ramp).” Right click the Color Ramps folder on the right. with lighter shades representing lower values and darker shades representing higher values. Customizing a color ramp You can create your own color ramp if you are not happy with any of the default choices. choose “new. depending upon the quality of your printer. 1 2 3 3 | M A k I n G M A P S 39 . Here you can play with the hue(H). Give your new color ramp a name and close the Type the name of the new color in the Contents window. and value(V). But keep in mind that it may be impossible to distinguish between more than four or five shades of the same color. or intuitive color schemes such as yellow to orange to red or yellow to green to blue.” then “Style Manager. go to “more colors” when choosing a color from the symbol selector. then a second color for Color 2. Your new color ramps should appear at the top of the dropdown list of color ramps in the Symbology tab.” and elect Algorithmic Color Ramp. To fine tune colors. go to the “Tools” menu and click on the folder called “ESRI.Graduated color works best when you use the same shade of a single color.
random. To make these a color ramp that you can then choose for other layers.You can also create your own color ramp by manually picking colors in the Symobology tab. and preset color ramps that can be created in ArcGIS in the help section.” You can find a more detailed explanation of algorithmic. highlight the middle (other than first and last colors) and choose “ramp colors. 40 H I l l I E R | U S I n G A R c V I E w 9 . 2 . multi-part.
so that you are happy with the value ranges. This may involve changing the background from white to “No color” so you can draw a layer symbolized with a fill pattern on top of a layer with solid colors in order to see the relationship between two different attributes. or instead of.Fill Patterns You can use different patterns in addition to. Click on the Properties button to fine-tune the fill pattern. using different colors to represent different values. Patterns are particularly helpful when you are restricted to printing maps in black and white. Set the number of classes and the method of classification. Choose “Graduated Colors” from the Symbology tab and select the field with the values you want to display. Then click on the symbols and change the fill using the symbol selector. 3 | M A k I n G M A P S 41 .
” From “Field Selection. medians. For example. but averages. Change this as needed to create dot densities that have enough dots to show variation but not so many that they are all on top of each other. as they do in a point layer. One major limitation of this type of map is that the dots may be distributed across parts of the polygon that don’t make sense. and rates are not.” and “Max” boxes will give you a preview of how your map will look. Click on “Quantities” and “dot density.Dot Density Dot density maps use randomly placed dots within polygons to represent different values for aggregate data. The “Dot Value” indicates how many units each dot represents. You can change the color of the dot by clicking on it under “Symbol” in the top right part of the screen. at least to start). If you use this option. Counts (such as the total number of households on public assistance) are appropriate for dot density maps. if you use dot density to show the number of foreign-born in a map of counties. or keep the default (which is advisable. the dots might appear in non-residential areas. Checking “maintain density” will ensure that the dot density looks the same as you zoom in and out (by making the dots bigger and smaller).” “Mean. Choose your dot size. open the Layer Properties and make the Symbology tab active. The “Min. Failing to do so may generate confusion and concern about data confidentiality. 2 . 42 H I l l I E R | U S I n G A R c V I E w 9 . They provide an alternative to choropleth maps for count data.” choose the field you wish to use as the basis for the map. To create a dot density map. You can avoid this problem by selecting a “mask” (such as parks and industrial areas) where dots should not be placed. be sure to remember—and carefully communicate on your map—that the points do not represent precise locations.
create an expression such as “[TotalPop] = 0. height). Click on the Size button if you want to have different size pie charts depending upon the total (such as total population). click on “Charts” and “Pie” from the Symbology tab. Pies contain a lot of information. Pie charts are especially good for showing proportions. they add up to 100 percent (you may need to create and calculate a new “other” field in your attribute table before using charts). For example. For the pies to work. individual pie pieces can be used to show the breakdown in race for the population in a census tract. 3 | M A k I n G M A P S 43 . If you choose to “Vary size using a field.” ArcView will use “leader lines” to indicate where the pie charts belong if there is no room to display them within the map feature. rotation. To do this. so that you don’t have too many colors in your map). If you check “Prevent Chart Overlap. Make sure that together. Holding down the shift key. you must be able to put every person into a racial group. To create pie charts.Pie Charts Charts are good for showing multiple values and the relationship between values on different variables. select the fields that you want to include. so it can be difficult to display them clearly. or you must use an “other” category. Click on the Properties button to make adjustments to the look of the pie (3D.” You may need to play with the minimum size on the previous screen to make the maximum size pie chart a reasonable size. click on the Exclusion button and. Click on the “Background” button to change the color or fill (“Hollow” or white backgrounds might be best. using the appropriate field name.” you may need to exclude records with a zero value.
2 . the map on the right compares the total population by block group to the total number of households. 44 H I l l I E R | U S I n G A R c V I E w 9 . all of the subsets.” Stacked Charts Stacked charts can be used to compare values on two or more variables (such as race) that are subsets of a larger variable (such as total population) when you don’t know. For example. You have many of the same options for formatting (size.Bar/Column Charts Bar charts can be used to compare values on two or more variables that do not represent proportions (they don’t have to be subsets that add to 100 percent). color) that you have with the other types of charts. To switch from column (vertical) to bar (horizontal) charts. go to Properties on the Symbology tab of Layer Properties and switch the radio button under “Orientation. or don’t want to display.
Labeling features can be frustrating and tedious, but labeling features well is important to making your maps readable and communicating their meaning, so it’s worth the effort to learn.
Using Text Boxes to Label Features
You can place text on a map in order to label map features. The text tools require that you type the feature name yourself while the label tools take advantage of feature names stored in the attribute table. The text tool can work well if you only have a few map features to label. Click on the button marked “A” on the drawing toolbar. The callout text tool works similarly, except that it allows you to place your text away from the map feature while still indicating what is being labeled. Click on the tool and then click on your map feature. Before letting go, you can move the cursor to where you would like the label to be. Type your label. Using the “Select Items” tool, you can move the text box so that it is closer or further from the map feature. The yellow background with black text may not be what you want (actually, it probably won’t be what you want).
This will bring up seven different text and label options. Click on the “A.” Click on your map where you want your text to appear and type your label in the text box. Hit the enter key, or click your cursor outside the text box to complete. You can move the text around using the “Select Elements” tool. Double clicking on the text will bring up the Properties, where you can change the size and font (using the “Change Symbol” button).
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From the “text properties” dialogue box, choose “change symbol,” then “properties,” then the “advanced text” tab, then the “properties” button below “text background”. From here, you can choose between two different style callouts. Click on the “symbol” button to change the background color.
Manually Placing Labels
Using the label tools in ArcMap, rather than the text tools, allows you to use the values in a layer’s attribute table for your labels (in other words, you don’t have to type the label out as you do with the text tools). By manually placing labels, you also avoid having your labels act as a group (which happens with auto labeling), so it’s easier to move or edit a single label. Before you can use the label tools in ArcMap, you need to indicate which field in the attribute table of your map layer you want to use as the basis for labels. From Layer Properties, click on the “Labels” tab. Leave the “label features in this layer” box empty (clicking this creates auto labels). Choose the appropriate field from the Label Field dropdown menu. Click on symbol to change the size, style, or font for your labels. (Guessing what size to make
A third option is the spline text tool. This allows you to write text along a curved line. This works well for labeling rivers and curvy roads. Click on the spline tool, then click on the starting point for your label. Continue to click along the curve (you don’t need to make many clicks) and double click to finish. Then type your label in the text box. You will probably need to try this several times to get a label with which you are happy (just click on the label with the “Select Elements” tool and hit the “delete” key to delete a label).
your labels is difficult and you will probably need to make small adjustments
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after seeing what works). Using the “Placement Properties” button, you can instruct ArcView what to do about duplicate labels. The “Scale Range” allows you to instruct ArcView when to draw or not draw labels, depending on the extent. In order to do this, you need to know the exact scales you’ll be using (so you probably just want to leave this alone). The “Label Styles” button gives you access to some fancier label options. The highway labels are particularly helpful. Now you can use the label tool to manually label your map features. Close the “Layer Properties” dialog box. Click on the button marked “A” on the drawing toolbar and choose the “Label” tool.
You may find it easier to automatically label all of your features. This saves time if you are happy with the way the labels look, but it offers you much less control over the label placement. When you automatically label features, the labels are “dynamic” so changes you make to one (moving it, changing the style) are made to all. To label your map features automatically, go to Layer Properties, click on the Label tab, and put a check mark in the “Label Features in this layer” box. You can also label automatically by right clicking a map layer and going to “Label Features.” To delete your labels, you’ll need to return to the Label Properties box and remove the check mark from “Label Features in this layer” box or right click and go to “Label Features.” You can select “In the map” as a place to store the annotation.
Converting Labels to Annotation
One solution to the problem that auto labeling presents with groups of labels The “Labeling Options” window will open. Decide if you want ArcView to decide the best label position or if you want to determine that yourself. The “Choose a style” radio button gives you access to those fancier labels again. You can move these labels (using the “Select Elements” tool) and change their size and style (double click to bring up Properties). You can delete a label by clicking on it and pressing the delete key. is to convert them to annotation. This allows them to function as individual text boxes so you can change the style for a single label. To do this, right click on your map layer after labeling it and go to “Convert Labels to Annotation.”
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You can select a halo color other than white and adjust the thickness (1.” and select the “mask” tab.5 point may be enough). 48 H I l l I E R | U S I n G A R c V I E w 9 . it will stand out. By creating a halo around the label. To create a halo.” “properties. double-click on the label text to bring up the “Properties” dialog box. Choose the “halo” radio button. then click “change symbol.Using a Halo with Labels Sometimes labels are difficult to see on top of a map that includes many different shades and colors. 2 .
From here you can choose a different style or color frame (to get rid of it altogether.” 3 | M A k I n G M A P S 49 . and image—to your layout. scale bar. choose “no color” from the color selector). The fixed zoom tools in the Layout toolbar work like the ones on the Tools toolbar. use the pan tool in the Tools toolbar. you have access to a different range of tools and use the Layout toolbar to navigate. The “Zoom to whole page” button is especially useful. Each of these will be separate objects in your Layout View When you open ArcMap. you can use the zoom tools on the Tools toolbar or on the Layout toolbar. you get a much better idea of how your map will look when it’s printed. Click on the “Frame” tab. You can remove this by right clicking on the border (so the line is turquoise and perforated) and going to “Properties. legend.deSIgnIng Map layoutS Displaying data so that you can analyze spatial patterns on a computer screen is one thing. ArcMap thinks of these as distinct functions and makes available a series of tools for designing map layouts that you don’t need until you are ready to print. you’ll need to change the X and Y offset to something other than 0). When you switch to the Layout View. These options allow you to add elements—including a title. printing out a map for other people to look at is quite another. ArcMap will automatically place a border (“neat line”) around your map. you are in “Data View” and use the Tools toolbar to navigate your map. To move just your map (and not the whole page).” click on the icon at the bottom of your map display that looks like a piece of paper (next to the globe icon) or. You can also change the background color and add a shadow (to add a shadow. To make your map larger or smaller on the page. To switch to “Layout View. from the View menu. In Layout View. One of the biggest differences in Layout View is that many more options in the “Insert” menu become active. The Layout toolbar also includes a pan tool that you can use to move your whole layout. north arrow. go to Layout View.
Adding a Legend Unless your labels are able to fully explain your map features. You can add text in the Layout View. click the “Preview” button again and click “Next. this won’t affect the order in which they are drawn).” Your first choice is what map layers you want included. the layout view is probably more confusing to look at from the screen because it adds so many elements and usually shrinks your map). click on the name and hit the up or down arrows (don’t worry.” you can specify ruler units and turn on and off rulers and grids when the “Layout Options” tab is highlighted. Choosing to “snap” to the grid or rulers will help you to line up objects. The order your layers are listed under “Legend Items” will correspond to the order in which they appear in your legend. To remove a layer from the legend. from the Insert menu go to “Legend. 50 H I l l I E R | U S I n G A R c V I E w 9 . rivers. make the adjustment here. from the Insert menu go to “Title. click on its name on the right side of this first screen and click on the “<” button. You won’t see any of them if you switch back to Data View since they are meant to clarify printed maps. Adding a Title To add a title. but it will also limit your ability to make fine-level adjustments. This may not be the case if you have layers such as a county boundary.” Type your title in the text box and hit the enter key or click the cursor outside the text box. To see what your legend will look like (before working your way through the rest of the screens).” On the second screen of the Legend Working with Grids and Rulers You can bring up a number of options aimed at helping you to place the objects within your layout by right clicking in your layout outside of the neat lines. 2 . Otherwise. not help you interpret your map on screen (in fact. you will want a legend on your layout. To add a legend. Double click on the title to bring up the Properties where you can make changes to the text and formatting. To change the order. click the “Preview” button. ArcMap gives you great flexibility in formatting your legend. you can click the Finish button and skip the other steps.layout that can be moved and resized through their Properties. From “Options. If you want more than one column in your legend. but you are better off trying to label features from the Data View. or other obvious features that don’t need to be included in the legend. using the label or text tools. ArcView will guess that you want to include all active layers. and all the choices can be overwhelming. If you are satisfied with it.
but depending upon your layout it may be helpful. The legend will use the same names that appear in the table of contents. click once on the map layer name. then click again (but not quickly). The third screen allows you to create a frame and shadow around your legend (not necessary. For example. you can give your legend a title or leave the word “Legend” as the title (or just leave it blank). particularly if you gave your layout a background color). Be careful not to change the numbers listed Cleaning up your map legend Chances are that you’ll need to clean up your legend at this point. You can also change the map label names from the “Layer Properties” dialog box. You may also need to translate some of the values that appear in your legend. respectively.Wizard. from the “General” tab. You can change the label names in the table of contents without changing the name of the shapefiles on your computer. double click on it to bring up Properties. you can change the symbols and symbol size used to represent lines and polygons in your layout.” To make changes after you have created your legend. The label name 3 | M A k I n G M A P S 51 . you may choose to symbolize a parcel shapefile with two different colors for the codes “1000” and “9999” which represent streets and sidewalks. From the “Symbology” tab. you can make adjustments to the spacing between items in your legend. allowing you to make changes. should become highlighted. Click “Finish. On the fourth screen. From the table of contents. Some of your map layer names may have underscores or other cryptic notations. type in “street” and “sidewalk” under the Labels. On the final screen.
be sure to add $ and commas. Including too many makes your map confusing and deceiving. 2 . If your number looks like a decimal (0. For income.15 for 15%).” Here you can change the number of decimals (in most cases. since your data is not that precise). you can use 1 or no digits after the decimal place. 52 H I l l I E R | U S I n G A R c V I E w 9 .under “Value” because this will change your map.” Select “percentage” from the right. click on the word “Label” in the “Symbology” tab and choose “format labels. For maps symbolized using graduate colors. you may also want to make adjustments using the “Label” section of the “Symbology” tab. For percentages. choose the second radio button and click on “Numeric option.
To add scale text. choose the units used for the original map projection (see “Working with Projections”). go to Properties. particularly if this is important to your audience and you deliberately chose a scale (as opposed to maximizing the size of your map based on the size of your page). right click in the layout (anywhere inside the neat lines). Double click to change the size or style. Once 3 | M A k I n G M A P S 53 . you can choose any display units you want. from feet to miles or km. here.” Choose a style from the “North Arrow Selector” (preferably something simple. You can move it around on your layout by clicking on it. Consider a small north arrow and one that is discreet. You can set these from the Data View or Layout View. from the Insert menu. Adding a Scale Bar To add a scale bar. No Yes Adding Scale Text You may wish to include a text description of the map scale. this is set. you must identify the appropriate units for your map. from the Insert menu go to “Scale Text.” you will need to define your map projection before proceeding. and make the General tab active. where you can make changes to the format and units. From the map units dropdown menu. If you do wish to add a north arrow. it is definitely necessary). You can also change the division units. You can move or resize it by clicking on it. from the Insert menu go to “North Arrow.” Your scale bar should appear on your map. where you can change the number of divisions and as well as the font size (by clicking the Symbol button or from the format tab). and small). From Layout View.” Click on a style and hit “OK.Adding a North Arrow You may decide that a north arrow is not necessary (unless you choose to rotate your map so that north is no longer towards the top of the page. in that case. go to “Scale bar. If your units read “unknown units. Double click to bring up the Properties. To add your scale bar.” Double click on the scale text in your layout to bring up the Properties.
Adding Group Layers Most of the time you will only need one data frame in a map document. To create a second data frame. From the View menu. If you do this. you’ll need two or more data frames. To restore the original orientation. either because you can’t fit everything (such as Alaska and Hawaii) on your main map. your north arrow will adjust to indicate which direction is north. But if you need to include more than one map in your layout (including the same map at a different extent). click on the “Clear Rotation” button. you’ll just have one data frame (called “Layer”) and every map layer you add to your map document becomes part of this frame. you want to show a series of small multiples (same map with different variables). 2 . moving your map to change the rotation. from the Insert Menu go to “Add Group Layer.” 54 H I l l I E R | U S I n G A R c V I E w 9 . As you rotate your map. then click and hold down on your map. When you open ArcMap. go to Toolbars (or just right click on a gray part of the GUI) and Data Frame Tools. make sure that you have a north arrow on your map. Working with data frames can make your map document complicated and prone to crash. MultIple-Map layoutS You may need to create a printed map that includes more than one map.Rotating a Map You can rotate your map to better fit the page or to make it easier to read (just because you can do this doesn’t mean it’s a good idea). Click on the “Rotate Data Frame” button. or because you want to zoom into a small area for your main map and indicate on a smaller overview map what area the larger map covers.
You will likely need to resize and move these to fit together. It does not matter which one is listed first in the table of contents.” When you switch to the layout view. To do this. 3 | M A k I n G M A P S 55 . right click on its name and go to “Activate. right click on it and go to “Copy. Creating Inset Maps If you want to have an overview map that shows on a larger map the outline of the area your detailed map includes. Move your detail layer from the left to the right side. Then right click on the overview layer in your table of contents. Zoom in on your detail layer in the map view and resize it in the layout view so that it looks the way you want. Click on the “Frame” button to make changes to the outline of your box. you’ll need to create an extant rectangle.To add new data to a particular data frame. follow the instructions above to create two map layers: a detail layer and an overview layer. From “Properties” click on the “Extent Rectangle” tab. one for each data frame. If you want to move a layer to a different data frame once it is in ArcMap. it matters which one is active. you will see that there are two map images.” Then right click on the name of the data frame where you want to move it and go to “Paste Layer. go to “Add Data”). from the Insert menu. right click on its name and go to “Add Data” or highlight its name and use the Add Data button (or. To display the layers in a data frame.” The layers in only one data frame can be displayed in the map view at a given time.
This is probably the best option if you need to send someone a map or post a map on the Internet.TIF and . and anything else you added to the layout. From the File menu. However. so be sure to click on the “options’ button when you export and increase the resolution to at least 200 dpi (300 dpi will be as good as you need for most things). . 56 H I l l I E R | U S I n G A R c V I E w 9 .jpg format will compromise the quality of your image. you will probably have the best results printing them from ArcView.JPG: The . go to “Export Map.exportIng MapS If you just need paper copies of your maps. you’ll want to export from Layout View. But if you need to insert maps into Power Point or word processing files.EPS: The .” There are many options for export formats in the “Save as type” drop downmenu. but they result in larger files. but this will not result in a presentation-quality map. scale bars. legends. 2 . north arrows.PDF: The . you can take a screen capture (push the print screen button or alt + print screen buttons.jpg format is good because it stores your map in a fairly small file. if you want your exported map to include titles. . will need to export your maps.eps formats work well if you are going to open your maps in a graphics software package.pdf format allows you to open the map directly (without inserting it into PowerPoint or MS Word) as long as you have Acrobat Reader. then choose “paste”) and crop the image. The . Screen Capture: If all else fails.tif and . . Exporting Process You can export a map from ArcMap when you are in Data View or Layout View.
jpg. 3 | M A k I n G M A P S 57 .” then Navigate to you map image and click “Insert.Inserting Maps into Power Point Save your map as an . “Picture.” and “from file.” You may notice that there is a lot of white space around your map. Also. You are probably better off creating map titles in Power Point rather than ArcView. consider making the legend larger than usual (14 points or more) so that your audience can read it. You may have less flexibility in moving the map around than in PowerPoint. Inserting Maps into Microsoft Word Follow the same procedures for inserting a map into Microsoft Word. You must have the map image active (click on it so that you see small squares at the corners). but you should be able to crop and resize it. With Power Point open. go to the Insert menu. Eliminate this using the crop tool. you will shrink the whole image). Click on the crop tool and crop the image by clicking on one of the small boxes and dragging the cursor (if you do this without having the crop tool active. if you are making a map specifically for Power Point.
csv) and tab-delimited (. There can be any number of columns (fields). from the file menu. polyline.dbf). comma-delimited (. or in ArcMap). You can only see tables listed when the “source” tab is active. ArcMap will switch the table of contents from the “display” to “source” tab.dbf in EXCEL. There may be additional fields identifying attributes of the map feature (type of crime at a particular address. freeze columns. or polygon. 58 H I l l I E R | U S I n G A R c V I E w 9 . The rest of the fields will vary. ArcMap can read Excel (. For example. as it does map features. Two columns are standard: FID. This might be a street address. You can add attribute tables to ArcMap just as you do shapefiles. the feature ID.4 | ModIfyIng attrIbutes workIng wIth tableS Attribute Tables for Shapefiles Every shapefile has an attribute table associated with it. and export tables—without worrying about corrupting your data.” The table will have as many rows. number of people living in a census tract). 2 . dBase (. “Add Data. or other identifier that will allow you to match the information in your attribute table to map features in a shapefile. select records.” Your table should have at least one column that contains geographic information. You can work with tables—sort values.” When you add a table. X and Y coordinates. Open the table by right clicking on its name in the table of contents and going to “open. or records.tab) text tables but will only allow editing for . zip code. and Shape. Other Attribute Tables Often you will have attribute data in a table separate from your shapefile. generate summary statistics.txt tables to .dbf tables (you can convert . You can open the table by right clicking on the shapefile name and going to “open attribute table. census tract number. The total number of records will be shown at the bottom of your table.txt or . such as a census tract number or neighborhood name. ACCESS.xls). there will also be a column that identifies each map feature with a unique name. SPSS. which can be point. You cannot change any of the data in your table unless you go to “start editing” from the editor toolbar… except to add new fields or delete existing fields. you may have a census tract shapefile with no attribute information and a table with all of the 2000 census tract data. using the “add data” button or. In most cases.
so that all of the highlighted records become un-highlighted and all un-highlighted records become highlighted. choose “Switch Selection. Freezing Columns Freeze a column (meaning that it will remain in view even as you scroll) by right clicking on the field name and going to “Freeze/Unfreeze Column.” Summary Statistics You can bring up summary statistics for any numeric field (numeric fields will be justified right) by right clicking on the field name and choosing “Statistics. From the options menu. At the bottom of the table. You can switch the selection.” Selecting Records You can select a subset of your records to look at more closely in a number of different ways.” You can obtain summary statistics on additional fields from the drop down menu.” You can also select all records or clear selection from the options menu. hold the control key down. ArcMap will indicate how many of the total records are highlighted. Click on the “Selected” button to view only the selected records. You can highlight an individual record (row) by clicking in the gray area at the far left side of the table. To highlight multiple records. 4 | M o d I F Y I n G A T T R I B U T E S 59 .Sorting Records You can sort values in an attribute table by right clicking on the field name and going to “sort ascending” or “sort descending.
need to convert a . but in your original file on your hard drive.dbf. 2 .” Remove the check mark next to “read only.” If this option is grayed out. and go to “properties. you can edit values in an existing field or create a new field and calculate new values. With your table open. because you have made changes. up to 19 characters Float: numeric.*. Go to “Add Field.” If you have some records highlighted.txt table to . This can be a free-standing table or one that is associated with a map layer. as well. you can choose to export just the selected records or all of the records. no decimal place. but ArcView has fairly sophisticated tools for calculating values. right click.dbf tables can be edited.” give your field a name. Keep in mind that you cannot change the format (text. find your table on your harddrive (through Windows Explorer or My Computer. In ArcView.&. open your table in ArcMap (you can also add fields from ArcCatalog). not through ArcCatalog). Creating a New Field To create a new field. so if you need to transform the format of a column.$. To change this.~ or spaces and keep your field name to 10 or fewer characters. H I l l I E R | U S I n G A R c V I E w 9 .#.” ArcMap will give you a warning that the deletion is permanent and not reversible. up to 19 characters Long integer: numeric. Do not use ?. no decimal place. choose the type of field. with decimal place. go to the options menu and “Export. you do not have permission to edit the table. Most likely. this is because the “read only” box is checked in the table properties.!. integer.” From “Add Field.Exporting Tables You may need to export your table from ArcMap. calculatIng valueS In tableS You may find it easier to edit your attribute tables outside of ArcView. From the dropdown menu.@. but only . Do this with caution. you will need to create a new field. or for any other reason. (default is one place before 60 Delete Field You can delete a field by right clicking on its name and going to “Delete Field. make your table bigger. This may happen automatically when you copy data off a cd. Click on the “options” button (if you do not see the options button. Different field types allow different types of values: Short integer: numeric. Changes will be permanent not just within your map document. it’s in the lower right corner). long integer) of an existing column.
warning that you will not be able to undo your results. specify length (default = 50 characters) Date: can include time and date Depending upon the field. click on the Field”). so you will need to use the calculator. then “Calculate Calculating Values Outside an Edit Session To calculate the value of your new field (or an old field). If your value is a constant. You can create an expression by double clicking on the field names. You can also calculate values from ArcToolbox (under “Data Management Tools”. field name with the total 65 and up. or accept the defaults by leaving them 0. ArcMap will only perform calculations on the highlighted records. with decimal place (default is 7 places before the decimal and 11 after) Text: numbers or letters.” ArcMap will bring up the Field Calculator. to calculate the percent of the population 65 and up. More likely. then “Add Field”). you can simply type the value in the box at the bottom. you may need to specific the scale (number of places) and precision (number of places to the right of the decimal point). NOTE: You can also add a new field from ArcToolbox (under “Data Management Tools”. 4 | M o d I F Y I n G A T T R I B U T E S 61 . If any of the records in your table are highlighted. and click on the field name with the total population. Say “yes.decimal and 11 after) Double: numeric. your new value will be based on values in other fields.” ArcMap will ask you if you are sure that you want to calculate values outside an edit session. For example. right click on its name and go to “Calculate Values. click on the “/” button.
ArcMap will not allow you to divide by zero. from the edit menu. just described. Calculating Values Inside an Edit Session When you need to calculate a new variable. choose “start editing. Do this by right clicking the field with your denominator and sorting ascending. the best approach is to calculate a value outside an edit session. go to “stop editing” in the edit toolbar and say “yes” to saving edits. you need to select only the records where the denominator is something other than zero.Calculating Values on Selected Records You can get an error while calculating values for many different reasons. From the options menu. Hold down the control key and highlight all the records with a zero. 2 . you may want to try editing inside an edit session. go to “start editing”). choose “Switch Selection” so that all of the records with non-zero values are highlighted. Finding & Replacing Values You can find and replace values in a table systematically from the options menu. Go the Edit toolbar and. When you are finished. Start by selecting the records with a zero in the denominator (because there are fewer of these). so you need to identify the directory that contains the table you wish to edit. so if the denominator (total population in example above) is zero for any of your records. Now you should be able to proceed with calculating values. ArcMap will not calculate any of the values. Open your table and double-click on the value in your table you wish to edit. you must be have started an edit session (from the edit toolbar. But when you need to change the value on just one or two values. 62 H I l l I E R | U S I n G A R c V I E w 9 .” You can only edit the contents of one directory at a time in an edit session. In order to replace values. To get around this problem.
The new layer will be added automatically to the table of contents when ArcView is done calculating the area. but it is easier using ArcToolbox. You can calculate area through ArcToolbox or through the Field Calculator.calculatIng area. “Calculate Area” can be found in the Spatial Statistics Tools section. If your shapefile is missing this field or if you have edited the shape and size of the map features. under “Utilities. Area can be especially helpful when you are trying to normalize values and create densities (calculating persons per square mile. for example). you will need to calculate area. The units will be what is used by the projection system for that map layer.” Choose the polygon layer for which you want to calculate area. yourself. perIMeter & length Calculating Area Usually there will be a field called “area” in a shapefile when you receive it that indicates the area of each polygon map feature. then determine a name and location for the new shapefile you will create. 4 | M o d I F Y I n G A T T R I B U T E S 63 .
” Create a field called “Perimeter. If not. or recalculate. the length of the line segments that make up a line shapefile (such as streets or railroad tracks).” Calculating Length You may also need to calculate.” Call your field “Area” or “New_Area” if a field called “Area” already exists.” Create a field called “Length. Choose “double” as the style and click “ok. 2 . open the attribute table associated with your polygon shapefile (right click on the name in the table of contents and go to “Open Attribute Table”). and click “OK. proceed as you would to calculate area. click on the “search” tab and type “making field calculations. You can copy and paste this script directly from the ArcView help (or from this manual).” 64 H I l l I E R | U S I n G A R c V I E w 9 .” Right click on the heading of your new column and go to “Field Calculator.You can also calculate are using the Field Calculator. you may inherit polygon shapefiles with a perimeter field. You will need to use the Field Calculator to calculate perimeter.” Check “Advanced” and type the following into the first text box: Dim dblPerimeter as double Dim pCurve as ICurve Set pCurve = [shape] dblPerimeter = pCurve. go to “Add Field. and click “OK.” Calculating Perimeter As with area. click on “Options” and go to “Add Field.area Type “dblArea” in the next box and click “OK”. Open the attribute table.” choose “double” for the style.” choose “double” for the style. click on “Options” and go to “Add Field.Length Type “dblPerimeter” in the second text box and click “OK. Open the attribute table. or if you need to recalculate it. From the ArcView help menu. First.” Right click on your new field and go to “Field Calculator.” Check “Advanced” and type the following in the first text box: Dim dblArea as double Dim pArea as IArea Set pArea = [shape] dblArea = pArea. From the options menu.
check the spatial reference properties. this is decimal degrees (not particularly helpful for understanding area).Right click on the heading of your new column and go to “Field Calculator. divide the area by (5.280) = 27. For projected shapefiles.400.com/length.344) = 2. If you are not sure what units ArcMap is using.609.Length Type “dblLength” in the second text box and click “OK.” Most likely. To convert square meters to square miles.” With the “Fields” tab active. From ArcCatalog.gr/converter/measurements.” Changing Units ArcMap will calculate area based on the map units used for the projection in which the shapefile is stored.344 *1.translatum. For unprojected data.988.htm or http://www. Look for the unit listed next to “Linear Unit. click on the field name “Shape” and then click on the “…” next to the “Spatial Reference” at the bottom of the Field Properties. visit http://www. For more on conversions.280*5.609.onlineconversion. To convert meters to miles.” Check “Advanced” and type the following into the first text box: Dim dblLength as double Dim pCurve as Icurve Set pCurve = [shape] dblLength = pCurve.344.htm. right click on the shapefile name and go to “Properties. 4 | M o d I F Y I n G A T T R I B U T E S 65 . the most common map units are meters and feet.589. divide by 1. To convert square feet to square miles. To convert feet to miles (for perimeter and length).609.110336.878. divide by (1. your data will be in projections using feet or meters as the map unit.280. divide the area by 5.
go to options. You can also add XY coordinates through the new X and Y columns and using a Visual Basic script to calculating the X and Y values (coordinates).” and go to “Export. With you table open. With your attribute table open. go to “Add XY Data” and select your table from the drop down menu (ArcMap will probably have done this for you already).” Say “yes” and add the new table to your existing map. The easiest way to do this is by using “Add XY Coordinates” in ArcToolbox (under “Data Management Tools” go to “Features” to fine “Add XY Coordinates”). then close the table.” The coordinates will be in whatever units are defined by your projection (often feet or meters). Simply choose the point layer you want to assign XY coordinates and click “OK. From the tools menu.” type “Double. click on “Options. you may need to add XY coordinates to an existing layer containing points. add new field called “X.creatIng xy coordInateS Adding XY Coordinates to a Point Layer Just as you may need to convert a table with XY data into a map layer. You can check the new XY coordinates by mapping them. 2 .” Your table of contents should now show two identical point layers. Click “ok.” 66 H I l l I E R | U S I n G A R c V I E w 9 .
The script for calculating XY coordinates can be found in ArcGIS Desktop Help by clicking on the “search” tab. Click “ok.” Follow the same steps to create and calculate a Y field. 4 | M o d I F Y I n G A T T R I B U T E S 67 .X Then type “dblX” in the smaller text box (that says “X =”) in the text box directly under the X field name. changing the Xs in the VB script to Y.Right click at the top of your new column and go to “Field Calculator…” Check “Advanced” and type the following in the first box (that says “Pre-logic VBA Script Code”): Dim dblX As Double Dim pPoint As IPoint Set pPoint = [Shape] dblX = pPoint.” Accessing the script this way will allow you to copy and paste the script. the typing “making field calculations.
click on “Options. the typing “making field calculations.” Right click at the top of your new column and go to “Calculate Values…” Check “Advanced” and type the following in the first box (that says “Pre-logic VBA Script Code”): Dim dblX As Double Dim pArea As IArea Set pArea = [Shape] dblX = pArea.” Follow the same steps to create and calculate a Y field.” Say “yes” and add the new table to your existing map.” Accessing the script this way will allow you to copy and paste the script. With your attribute table open. Click “ok. From the tools menu.Centroid. The script for calculating XY centroids can be found in ArcGIS Desktop Help by clicking on the “search” tab.” and go to “Export. 2 . Click “ok. You can check the new XY coordinates by mapping them.” type “Double. go to “Add XY Data” and select your table from the drop down menu (ArcMap will probably have done this for you already). go to options. then close the table.X Then type “dblX” in the smaller text box (that says “X =”) in the text box directly under the X field name. add new field called “X. 68 H I l l I E R | U S I n G A R c V I E w 9 .” Your table of contents should now show a new point layer that represents the centroid of your polygon layer. With you table open. changing the Xs in the VB script to Y.Adding XY Centroid Coordinates to Polygon Layer Adding the X and Y coordinates of the centroids of polygons is similar to adding X and Y coordinates to a point layer.
or match.joInIng tableS You can link map features to their attributes in GIS but only when your attributes are in the same file as your geographic data. go to “ Joins and Relates. Next. Tables with census data may contain multiple fields that uniquely identify each record that may have names such as “TRT2000. Keep in mind that ArcView is not checking to make sure that these keys match. you can join attributes to shapefiles for other data: zipcodes. If they are not. The values must be formatted in an identical way. look and see how they are justified. Right click on its name in the table of contents.” The field name doesn’t have to be the same in the attribute table and the shapefile in order to join them. choose the table you wish to join (this does not need to be added to ArcMap). you must edit one of the fields or create a new field and recalculate the values so that they match perfectly. 4 | M o d I F Y I n G A T T R I B U T E S To make sure that both columns are formatted the same way. counties. Identifying a key In order to join an attribute table to a shapefile. so you should double-check them (by opening both tables) before performing the join. You might think of a shapefile as a series of containers that can hold attribute data. In the second dropdown menu. This field is known as a key. You can join on a name (such as neighborhood name. Joining a table To join attribute data to a shapefile. or the name of an institution). Often you will obtain shapefiles that have no attribute data—in effect. when you will often obtain shapefiles for census tracts and blockgroups in separate files from the census attribute data (SF1 or SF3).” and “TRACTID.” “STFID. your data. identify the key you’ll use in your shapefile. Often you will have attributes stored in a separate table that you will need to join to a shapefile in order to symbolize your map with the data. This is especially common with census data. 69 . you must add the shapefile to ArcMap.” and then “ Join…”. While you may perform joins on census data most frequently. right justified columns are formatted as numbers. identify the key in this table. or unique identifier. empty containers. because it uniquely identifies each record in your table and shapefile on which ArcView can join. councilmanic districts. Choose “ Join attributes from a table” in the first dropdown menu. Finally. although keep in mind that differences in spelling and spacing will keep records from joining. you will need to identify a field that is common to your attribute table and the attribute table associated with your shapefile. Left justified columns are formatted as text. they just have to be formatted in the same way.
To make the join permanent. 2 . Give your new file a name (do not accept the default. The resulting shapefile will have variable names that are much shorter than those in the table created during the temporary join. The new field names will include the name of the attribute table from which it came. right click on the shapefile name.” so it creates a new shapefile. Individual records might not match because of problems with the key or because there are different numbers of records in each of your files. go to “Data. When you open your shapefile.shp”) and location. there should be new fields that contain the data from your attribute table. 70 H I l l I E R | U S I n G A R c V I E w 9 . meaning that some map features might have no values for some fields. or vice versa.From “Advanced. “Export_ Output. so if you add the shapefile to another map document. The default is to keep all records.” you can indicate what you want ArcView to do if all of the map features in the shapefile don’t have a match in the attribute table. you will not have the appended data.” and choose “Export Data…” This works like a “save as. The join holding the data together is not permanent.
You should now see a lightning bolt button in your Tools toolbar (previously it would be grayed out).” 4 | M o d I F Y I n G A T T R I B U T E S 71 . Click “OK” and “OK. Make sure that the “Identify Results” table brings up information relating to the right map layer. Right click on the text in the box on the left and go to “Add Hyperlink. Click on the lightning bolt and move the cursor over your map.” If nothing happens when you click on the hyperlink.” From the “Add Hyperlinks” box.addIng hyperlInkS Hyperlinks allow you to click on a map feature and bring up a relevant image (or website) rather than just the attribute values stored in your attribute table. Find the image file you were trying to link to using My Computer or Windows Explorer. You can add multiple hyperlinks to the same map feature using this method. from the “Identify Results” box. But for presentations using ArcGIS. you probably need to set or reset the default program for opening the image. Click on the map feature and your image should appear. right click on the text on the right and go to “Manage hyperlinks. To remove hyperlinks. click on the folder icon and navigate to the image you wish to link to. This is of limited use because the links will only work from inside ArcGIS. this hyperlink feature can be helpful. Click on the map feature you wish to link with the identify tool. ESRI and other vendors have developed a wide range of interactive online map systems that provide much greater utility than hyperlinks. right click on it.” then close the “Identify Results” box. and go to “Properties. When the cursor is over the map feature with the hyperlink. you should see the path name for the image appear.
” Start an edit session (from the Edit toolbar. tif) in the appropriate record. double click on the image file. Click on the map feature you wish to link with the identify tool and right click on the text in the box on the left and go to “Add Hyperlink. it might be easier to add them using the attribute table. choose the field that contains your hyperlinks. Click “OK” and “OK. c:/esri/maps/image. In ArcMap.Check the program listed next to “Open with. Type the full name of the image file. Create a new text field called “Hyperlinks. 2 . for example).” To make sure the new program can open your image file.” If none is listed. Now you need to make the hyperlink(s) active. double click on your shapefile name in the table of contents and. click on “Change” and pick a program (an image program or an internet browser. Put a check mark in the Hyperlinks box and. You can link to a website instead of an image. make the “Display” tab active. 72 H I l l I E R | U S I n G A R c V I E w 9 .” Adding Hyperlinks through Attribute Tables If you have more than a few hyperlinks for a map layer. this should also work for your hyperlink. If the software program opens and displays your image. go to “Start editing”). from the dropdown menu. from the Layer Properties dialogue. including the path (for example. Now you should be able to bring up the hyperlink using the lightning bolt button.
You can download these for free from the following site: http://arcdata. Intersections can be used (Lehigh Avenue & N Broad Street) but house ranges (123-127 N Broad Street) and PO boxes will not. The line segments also contain information about which side has even and odd house numbers.txt) that has a field with street addresses. Preparing Tabular Data In order to geocode.com/data/tiger2000/tiger_download.dbf. Creating an Address Locator In addition to a table with addresses. you will only be able to geocode addresses for one county at a time. so make sure you change these to addresses with a single house number before you try to geocode.cfm The street centerline file will be listed as “Line Features—Roads. . This is essentially a registration process in which you help ArcView to recognize the fields in the street centerline file so that it can prepare it for geocoding. you will need to collapse these into a single field. you also need a shapefile that includes information about all of the streets in your area. Street centerline files are available for each county in the United States through the US Census.xls. or comma-delimited . In order to geocode. A street centerline file is made up of line segments that represent certain ranges of house numbers.5 | Creating & aggregating Point Layers GeocodinG Geocoding refers to the process of transforming street addresses into map features. street direction. If the parts of the street address— house number. The image here shows how each section of a street centerline file has a known street name (ST_NAME) and address range (L_F_ADD and R_F_ADD). In order to be able to use the county street centerline file for geocoding. ArcView uses this information to locate the addresses in your table (called Foodsite_addresses here). Through the geocoding process. you need to have a table with addresses and a shapefile for streets that matches the geographic extent of your addresses.” If you use these files.esri. and designation/ type—are in separate fields. you need a table (. choose 73 5 | C r e a t i n g & a g g r e g a t i n g p o i n t l a y e r s . ArcMap will create a new point shapefile by matching each street name and number in your table to a place along a line segment in your streets shapefile that represents a certain range of house numbers. From ArcToolbox. ESRI also sells a product called ArcGIS StreetMap that allows you to geocode addresses for the entire country. Having a separate field with the zip code can also be helpful (keep this separate). you need to create an address locator from it. street name.
etc. For example. Look through the other styles to see which matches the data you have if your data has different or additional information.” The more fields that you have to help you geocode. St. click on the empty space under “Alias” and show ArcView the name of the appropriate field. 2 . including house number. First. Ave. direction. street name. At this point. the Field Names and Alias names in the space below should fill in. and designation (Rd. The “Reference Data” refers to your street centerline file. Click “OK” to finish. the more accurate your mapping will be. but the trade-off for this greater accuracy is often a lower match rate.).“Create Address Locator” (under “Geocoding Tools”). if you have zip codes in addition to street addresses you can use “US Streets with Zone. Click in the white space under “Role” and select “Primary table” from the dropdown menu. “US Streets” is the most basic and only requires that you have complete street addresses. If they do not. you need to identify the address style from the drop-down. 74 H i l l i e r | U s i n g a r C v i e w 9 .
The “Side Offset” option allows you to place points slightly away from the middle of the street centerline file. ArcView can geocode based on street intersections in addition to specific house numbers. While ArcView will know what side of the street your address falls on. click on “Add” and navigate to where you saved your address locator (this will likely be in the same folder where your street centerline file is located). 15-20 feet is adequate. and a name and location for the new point shapefile that will be created. the field that contains the street address.” On the next screen. 5 | C r e a t i n g & a g g r e g a t i n g p o i n t l a y e r s 75 . Essentially. your points will appear to fall directly on the centerline unless you specify an offset. If the spelling of the street name is slightly different or an appropriate range of house numbers cannot be located. ArcView needs to match the house numbers and street names in your tabular data with information in the streets shapefile. you need to identify the table with your addresses. In the “Intersections” section you can identify symbols (or “AND”) used in your tabular data to indicate intersections. ArcView will assign the match a less than perfect score (100 is a perfect match). but it is easier to go to the Tools menu.Geocoding Addresses You can geocode addresses through ArcToolbox. Under “Output Fields. select “Geocoding” and “Geocoding Addresses.” ArcView will add X and Y fields to the point shapefile with your addresses. you don’t need to do it again (unless you go to a new computer).” if you check “X and Y coordinates. The “Geocoding Options” allow you to indicate the level of sensitivity for the matching process.” In the “Add Address Locator” screen. Once you click “OK. Once you have created an address locator.” then click “OK. Click “Add.” a new address locator should be listed under “Address Locators” in the Catalog.
several fields to your original address table. click on the “rematch” button and then select “unmatched addresses” from the drop-down menu on the next screen.Click “OK” to exit the “Geocoding Options” and then “OK” again to start the automatic geocoding process. The “Side” field indicates on which side of the street the address was matched. are missing a space (725 E. The “Score” field indicates how closely the record matched the street centerline file. After a few seconds (longer if you have thousands of records). ArcView will give you a report showing how many matches were made. you will see that the geocoding process added To look at these and match them one at a time. You may be able to see errors in your addresses that you can correct by going through them one at a time. The problem may be that you have a series of addresses (210-220 South 34th Street). You can correct the address by clicking on the “Modify” button or simply making the change in the “Street or intersection” box. This will be the same as the original address unless you edited it during the “Interactive Review. If you open the attribute table associated with the new shapefile that the geocoding process created. The “Arc_Street” field is the address used in the match.Westmoreland Street) or a mis-spelled street name. Click on the best candidate. The “Status” field indicates whether the record was matched (M) or left unmatched (U).” 76 H i l l i e r | U s i n g a r C v i e w 9 . then click on the “Match” button. 3 . Click “Enter” to see if new candidates appear below. Click on the “close” button when you have corrected all the addresses that you are able.
Right click on the address locator and go to “properties. You may wish to do this if you had a low match rate and need to adjust the spelling sensitivity or want to match candidates that tie. Modifying your Address Locator You can modify the properties of your address locator after you have in ArcCatalog.” 5 | C r e a t i n g & a g g r e g a t i n g p o i n t l a y e r s 77 .Here you have access to the “Matching Options” that were available when you geocoded your addresses.
look for problems with Roosevelt Boulevard and numbered streets (particularly 2nd – 9th Street). If you have only an address or two to map. There is no guarantee that the matched records will be mapped in the right place. after finishing geocoding. Next. Be sure to write down the match rate so that you can report it later. and it has no attributes associated with it. Determining an acceptable match rate Aim for a match rate of at least 90 or 95 percent. open the attribute table and sort by “status” to review all the “U. you can take a shortcut. 2 . The most important thing to determine is if the error (the unmatched records) is random or systematic. Other times your addresses will look fine but simply won’t match the street centerline file. Keep in mind that this is only a graphic. with their score. choose “Find” and click on the “Address” tab. In Philadelphia. Review/Rematch Addresses and choose from the recently geocoded files. Do a spot check with the “Identify” tool to make sure that records mapped somewhere that makes sense to you. This is not a problem as long as you remember to go to the Edit toolbar and “stop editing” when you are finished. You will need to start an edit session in order to proceed.” unmatched records). you will need to do so. If you have done all that you can to gather complete and accurate addresses. Be sure to check for patterns in your unmatched records (either by interactively reviewing unmatched records or. it can easily be deleted or moved. Systematic error is not. but you cannot turn it on and off like map layer. random error is acceptable and probably unavoidable.Rematching Addresses You can resume the “Interactive Review” even after you’ve clicked “done” and stopped geocoding. You might choose to “Flash Candidate Location(s)” to make sure it’s mapping in the right area or “Add as Graphic(s)” if you want a marker at the location. Finding an individual address 78 H i l l i e r | U s i n g a r C v i e w 9 . go to Geocoding. From the File menu. If you have not already created an address locator. This From the tools menu. Often you will receive a list of addresses that contains some PO Box numbers or missing data that will prevent you from matching all your records. You can change the size and color of the graphic.” ArcView will display the possible matches below. Next. type in the address in the “Street or Intersection” box and click “Find. Right click on one of the addresses for mapping options. You may need to look up additional information before you can correct some addresses (such as missing “N” or “S” for street names). choose an address locator in the drop down menu.
choose the second radio button. choose your polygon layer. to another layer.Spatial JoinS Tabular joins use a common unique identifier to attach an attribute table to a shapefile. If you have points outside your polygon (for example. indicate that you want to join data to that layer based on spatial location. You must have a point theme and a polygon theme in ArcMap in order to do this. This may include only the polygon identifier (such as the census tract number) or the identifier and attributes. Assigning Area Characteristics to Points Using a spatial join.” The resulting point shapefile will have as many new columns as your polygon shapefile. you can determine into what area a point falls.” In the first dropdown menu. Spatial joins use common geography to append fields from one layer. For example. you might need to determine in what council district each public school falls in. Right click on the point theme. or events as well as to aggregate points by areas. or information about a layer. This allows you to assign the characteristics of an area—such as a census tract or city council district—to individual houses. Next.” and choose “ Join. go to “ Joins and Relates…. Specify the name and location of the new point shapefile that will be created and click “OK. if you have a census tract map of Philadelphia with points representing addresses in the city and just outside it). In the next dropdown menu. individuals. choose the first radio button so that each point is given all the attributes of the polygon it falls inside. 5 | C r e a t i n g & a g g r e g a t i n g p o i n t l a y e r s 79 .
and calculating it as equal to “Count”). the radio button should be set for the second from the top option. you can also determine how many points fall in each polygon. Aggregating Points by Polygons Using a spatial join.” If your points do not all fall within your polygons (for example. you might want to know how many schools fall in each council district. 2 .” for example. “Each polygon will be given a summary of the numeric attributes of the points that fall inside it. Finally. your new shapefile will have only one new field called “count. In the next dropdown menu. Next. You will probably want to change the name to something that you will remember (by creating a new field called “SchoolCount. choose the second radio button. You must have a point theme and a polygon theme in ArcMap in order to do this. specify the name and location of the new area shapefile that will be created. choose your point layer.” This will indicate how many points fall into each polygon. and a count field showing 80 H i l l i e r | U s i n g a r C v i e w 9 . if your schools attribute table included a column with the total number of children enrolled.” In the first dropdown menu. You can then decide if you want to summarize the attributes of your points by their areas in the boxes below (for example. Now you can use this count value as the basis of a thematic map. Click “OK. Choose “Sum” in a situation like this). For example. go to “ Joins and Relates…. indicate that you want to join data to that layer based on spatial location.” and choose “ Join. you have a map of city council districts and points representing addresses in the city and just outside it).” If you did not check any of the boxes to summarize the attributes of the points. you could summarize that data so that you know how many children are enrolled in schools in each council district. instead. Right click on the polygon theme.how many points fall inside it.
the spatial join dialog box will give you different options. you can determine which public library is closest to each school and how far that school is. Right click on the shapefile to which you want to join information (so in this example. if you have a shapefile for public schools and for libraries. choose “Joins and Relates” and then “Joins..From the first dropdown menu. The second radio button (more helpful for our example) allows you to identify the point in the second shapefile (library) that is closest to each point in the first shapefile (schools) as well as a distance field indicating how far apart they are. Add both point shapefiles to ArcMap. choose “join data from another layer based on spatial location. Notice in the table below that the Andoraa library is the closest library to the Depending upon the type of file you start with (right click on). For example. the public schools). you can calculate the distance between the points in one file to the closest point in the other file.” Then choose the library shapefile as the basis for the spatial join. The first radio button allows you to summarize the attribute for the points closest to each point in your first shapefile and gives you a count of how many points from the second shapefile are closest to each point in the first shapefile. If you use a spatial join between two point shapefiles. 5 | C r e a t i n g & a g g r e g a t i n g p o i n t l a y e r s 81 ..” Shawmont School 4328 feet away). Notice that ArcView will recognize that ou are joining Points to Points.
‘BROAD’). Click “Verify” to make sure ArcMap likes your expression. the query dialog is similar to the Field Calculator. The query shown to the left identifies all one-way streets that run south through Philadelphia. from the Selection menu go to “Select by Attributes. When you click 82 H i l l i e r | U s i n g a r C v i e w 9 . as part of getting to know your data. You can use these or type in your own. 2 .” our first choice is what layer in your map you wish to query (attribute queries are limited to a single layer). to create new values. or to answer your research questions.” the map features that satisfy your query will be highlighted with a bright blue outline. From here. In the Method drop down menu. “Apply. The values associated with each field will be displayed in the text box at the far right. connecting statements with “AND” or “OR” as necessary. you can identify a subset of map features based on their attributes or their location. You may use queries as an intermediary step. click on the Query Wizard button. You can import (Load) and save expressions using the buttons OR using Ctrl + C and Ctrl + V with a word processing file. Build an expression using the field names and functions. If you want help working through these steps. you need to decide whether you are building on a previous query or starting fresh. Select by Attribute To start a query. rather than numbers.6 | Querying & Measuring QueryinG by attribute With GIS. you need to put single quotes around them (for example. Note that if the values you input are text.
7 miles) of southbound one-way streets in Philadelphia.To review the selected records. or selecting from this selected group) or close the query dialog. 6 | q U e r r y i n g & m e a s U r i n g 83 .” bound one-way streets that are class 1 (highways) roads. You can also look at summary statistics for only the selected records by right clicking on a column name and going to “Statistics.432 feet (655. You could also select the subset of southTo see all of the selected records. You can perform an additional query (adding.” Choose the radio button regarding coordinate systems (you’ll probably want the default). You can calculate values on an existing or new field for only the selected records. we can see that there are 3. To un-select all records. Make sure you have “Selected Records” chosen in the Export drop down menu. right click on the map layer and go to “Open Attribute Table.” By looking at the statistics for the length field on the selected southbound one-way streets. from the Selection menu choose “Clear Selected Features.” Click on the Select button at the bottom to view only the selected records. going to “Data” and “Export Data. from the Selection menu.462. removing. The query shown here will add the northbound one-way streets to the already highlighted southbound one-way streets.” You can create a new shapefile that only includes your selected map features by right clicking on its name in the Table of Contents. go to “Zoom to Selected Records.
identify all the code 1 streets first. Select by Location To select features in a map layer based on their location. from the Selection menu go to “Select by Location. This query shows which charter schools are within ¼ mile (1320 feet) of public schools. For distance-based queries. then select the schools “within a distance” of 500 feet of the selected streets. you may be interested in which schools are located within 500 feet of class 1 (highways) streets. Combining Attribute and Location Queries The “Select by Attribute” and “Select by Location” dialogs do not allow you to mix the type of query. 84 H i l l i e r | U s i n g a r C v i e w 9 . 2 . you can perform attribute and location queries on the same map layer. But by performing one type of query first and then conducting a subsequent query on the selected records. and combining attribute and location queries really takes advantage of GIS functionality. you will be able to select your units as long as the map units have been specified in the Data Frame properties.QueryinG by location The ability to query based on the location of map features is something unique to GIS. Using the “Select by Attribute” dialog.” Your first choice involves the nature of the selection. The drop down menu then provides various relationships between the features in that layer and a subsequent layer (identified in the next drop down menu). put a check mark next to the map layer(s) whose features you wish to select. Are you starting from scratch or querying a subset of map features already selected? In the next box. For example.
it will not matter which query you do first. Assign the other records = 0 by going to “switch selection” from the “option” button on the bottom of the table.Using Query Results The turquoise highlight feature is meant to help you visualize relationships. create a new variable and symbolize it properly using the symbology tab. For example. Only the highlighted records will be assigned this value. Do this by opening the attribute table for the schools. As the resulting map shows. Once you have identified a subset of records. Double-check your results to make sure they make sense because it is easy to make a small mistake in building your query that can leave you with a completely wrong answer. remove. then go to “Field Calculator. if you want to create a map showing the schools that are located within 500 feet of highways. 6 | q U e r r y i n g & m e a s U r i n g 85 . or select from the records selected from the first query.” Set Class1500 = 1. several of the public schools in Northeast Philadelphia are within 500 feet of I-95. Just be sure that the selection method you choose for the second query allows you to add. but it is not meant for final maps. complete the query and then use the query results to create a dummy variable indicating which schools meet the query definition. Create a new variable called “Class1500” (for 500 feet within class 1 street) that is formatted as an integer. Often. You may need to try the query a couple of times to get it right. Right click on the new column.
Double click to finish. and the General tab) or in the Measure pop-up box. if you need to know the total length of Broad and Market Streets. The measure tool will use the map units particular to that map layers projection or the display units you specified in the Data Frame Properties. right click on the “length” column heading.MeaSurinG diStanceS Using the Measure Tool The measure tool allows you to draw a line. Select the features of interest. or a series of connected lines. go to “Select by Attributes” and select all line segments in the street centerline file called “BROAD” or “MARKET. 2 . Click on it and then click on your map at the starting point. or next point. For example. you can use the values in perimeter (polygons) and length (line) fields of the shapefile attribute tables. go to Properties. then right click on the perimeter or length field and go to “Summary. 86 H i l l i e r | U s i n g a r C v i e w 9 . repeating until you are done. to roughly measure the Euclidean (as the crow flies) distance between points. The black triangle pointing down includes various distance units to choose from.” The “sum” field will indicate the total distance.” The “sum” should indicate how long Broad and Market Streets are.” Then open the attribute table associated with the street centerline file. Move your cursor to your end point. and go to “Summary. Measuring with Attribute Data If you need more accurate measures of distance than you can get using the measure tool. You can change this from the Data Frame Properties (right click on the name of the Data Frame.
traffic conjestion. This is a rather crude measure that fails to take into consider that people can’t fly and must navigate one-way streets.Measuring Distance with Networks Both of these methods described above allow you to calculate Euclidean distance—as the crow flies. Specify a name and location for the new buffer shapefile. as well. If you are interested in seeing which schools fall within 500 feet of class 1 (highways). and other barriers. among other considerations. Note that ArcView will only buffer highlighted features if any of them are highlighted. then specify the distance and distance units. For analysis purposes. queries by location may be more helpful because they will allow you to actually select the schools within 500 feet of class 1 roads. You can create buffers using the Buffer tool in ArcToolbox (under Analysis Tools). such as street segments. so that you can visualize this relationship. Select the map layer you wish to buffer using the first dropdown menu. will be one continuous polygon. you can create a 500 foot buffer around class 1 streets. But you may want to create buffers. Using ArcView’s Network Analyst. it is possible to factor in travel times and traffic patterns. You may want to choose “all” from the “dissolve” dropdown so that the buffer around multiple map features. 6 | q U e r r y i n g & m e a s U r i n g 87 . bufferS Buffers allow you to visualize zones around map features.
and click the + key so that the distance appears in the list below. Choose the layer you wish to buffer and specify a name and location for the new file. 2 . choose the “Multiple Ring Buffers” Tool in ArcToolbox (under Analysis Tools). 88 H i l l i e r | U s i n g a r C v i e w 9 . Type in each distance. Use the symbology options in Map Layer Properties to represent the different rings with different colors. one at a time.Multiple Ring Buffers If you want to show several different distances at the same time.
If you need to do much editing of shapefiles. Deleting and Modifying Features In order to make changes to a shapefile. The shared boundary will be shown in green and the vertices along the shared boundary will become visible. you can move your map feature to a new location. choose “start editing. The directions provided here are very minimal. choose “Stop Editing” and say “yes” to saving edits. and dragging it. indicate which map layer you wish to edit. union. Most of the boundaries between polygons are shared boundaries. from the Editor menu on the Editor toolbar. clicking. From the Target drop down menu in the Editor toolbar. Notice that the vertices become visible and the Task menu automatically brings up “Modify a Feature. Click on the shared edit tool and double click anywhere on the shared boundary. use the geoprocessing tools such as clip. Notice that you do not have a “save as” option. line. double click on it.” If you have multiple shapefiles in your map document that are from different subdirectories on your computer.” You can reshape your feature by putting your cursor over a vertex. If possible. To save edits. intersect. and dissolve to make changes to your shapefiles rather than using the editing tools described below. click on the edit tool and click on the feature you wish to edit (it should become highlighted). (ArcView will show the last created vertex in red). To modify a line or polygon feature. or polygon). you need to use the shared edit tool. By clicking and holding down the mouse button. From the Editor toolbar. you must start an edit session. 7 | C r e a t i n g n e w g e o g r a p H i C f i l e s 89 . In order to move the boundary for both polygons (rather than creating an awkward gap). To edit an existing feature (point. then click outside the map feature to complete. Move a vertex. you should seek out additional resources (such as the ESRI Virtual Campus course on digitizing). You may want to make a backup of your original data before editing. You can add a vertex to a feature by right clicking on a green line and going to “insert vertex” (a new vertex will be created where you right click). you will need to specify which directory will be part of the edit session (you can only edit the files in a single folder at one time).7 | Creating new geograPhiC FiLes editinG ShapefileS Editing shapefiles is tricky—and a bit dangerous—territory. Click outside of the map feature to complete.
double clicking to complete. Click on the sketch tool and then draw a line through your polygon (the line does NOT have to be straight). 2 . Splitting Features Splitting polygon features involves creating a new line within an existing polygon. choose “Stop Editing” and say “yes” to saving edits. Updating Area. and Perimeter Keep in mind also that editing shapefiles can change attribute values that you may need to update. Using the edit tool and the shift key. Start an edit session and choose “Cut Polygon Features” from the Task drop down menu. from the Editor menu on the Editor toolbar.Merging Features In order to dissolve the boundaries between two or more polygon features. To save edits. click on the features you wish to merge (they should become highlighted). Length. from the Editor menu on the Editor toolbar. select the polygon you wish to split.” 90 H i l l i e r | U s i n g a r C v i e w 9 . choose “Stop Editing” and say “yes” to saving edits. To save edits. Follow the directions in the section of this guide entitled “Calculating Area. Using the edit tool. you must start an edit session.” You can also select map features based on their attributes by opening the attribute table and selecting the corresponding records. then from the Editor menu on the Editor toolbar select “Merge.
” You must define the projection for map layers before using any of these functions.” On the next screen. click on the folder to the right of “input feature class.tranSforMinG ShapefileS There are a number of different functions you can perform on map layers.” If the layer is already added to ArcMap. choose the column in from that layer’s attribute table that contains the information you wish to use for the dissolve. ArcMap will give the new shapefile that will be created a default name (adding “_Dissolve” to the input layer name).” ArcView will create a new shapefile that combines all of the map features (census tracts) into a single polygon (neighborhood). 7 | C r e a t i n g n e w g e o g r a p H i C f i l e s 91 . From ArcToolbox. they will still be dissolved into a “multipart feature. This must be an attribute for which multiple map features (polygons) have the exact same value. you need to identify the map layer whose features you wish to dissolve under “input features. the functions will only be performed on the selected features. you can use the dropdown menu.” Next. If you have selected a subset of features within a map layer. If you want to rename this or change the location. you can find “Dissolve” under “Data Management Tools” and “Generalization. Dissolve The dissolve operation allows you to collapse the boundaries between polygons if they share the same value on a particular attribute. For example. Several of them fall under the description of “overlay analysis. that result in new map layers. either based on location or attribute value. although keep in mind that nominal and categorical variables will work better than ratio variables. If polygons have the same value but are not contiguous. The values can be numbers or text. you could create a neighborhood map layer by assigning each census tract to a neighborhood and then dissolving the boundaries. Otherwise you will need to click on the folder icon to locate the may layer.
you can select “TEST” under “Scheme Type. 2 . If the column names were the same for all of the layers (as they could be for census tract files from different counties).” Under “input features. Append Appending allows you to incorporate two or more non-overlapping layers into a single map layer without changing their map features. and polygon layers. but you will need to add them one at a time. particularly if you merge street centerline files.” This will overwrite the existing layer. you can merge census tract files from several counties so that when you display the percent of homeowners. you must choose “NO_TEST.” Otherwise.” list all the map layers you wish to 92 H i l l i e r | U s i n g a r C v i e w 9 . Appending can save you time when it comes to symbolizing features and lead to more consistent symbology. From ArcToolbox.merge. you don’t have to repeat the process of classifying your data for each county. line. You can append point. so be sure to make a backup copy if necessary. If the columns in the attribute tables of all the input features are identical. For example. Keep in mind that these merged shapefiles can grow very large.” The resulting shapefile will contain all of the map features in the appended layers. You can use the dropdown menu if you have added the map layers to ArcMap. so you will need to specify an EXISTING layer in “output feature. A new layer will not automatically be created. you can find “Append” under “Data Management Tools” and “General. there will be values for each record in each column.
so if you need these be sure to recalculate them. The default name for the new shapefile will be the first input feature name plus “_Intersect.” If you want to change this or the location of the new file. you can find the “Intersect” function under “Analysis Tools” and “Overlay. From ArcToolbox. click on the folder to the right. census tracts were intersected with police districts. the resulting shapefile will contain polygons. as well. If you intersect polygon layers. two of which are sliver polygons. you can find “clip” under “Analysis Tools” and “Extract. Other attribute values maybe deceptive. Changing it will allow slightly mismatched map layers to be considered “coincident. The default name for the new shapefile will be the input feature name plus “_Clip. From ArcToolbox. the resulting shapefile will contain “polylines” that act like lines. In effect. click on the folder to the right. perimeter. you need to identify an input feature (the layer to be clipped) and the clip features (cookie cutter). You can intersect two polygon layers or a line and polygon layer. Adjusting the cluster tolerance can help you avoid sliver polygons. this combines the union (described below) and clip operations. select the input features. In the example at right.” On the next screen. not real differences in their actual boundaries. Length.” If you want to change this or the location of the new file.” On the next screen.” Intersect Intersect allows you to fuse two overlapping layers together to create a new shapefile that includes the attributes of both layers for the area in which the layers overlap. For example. The result was many sliver polygons resulting from slight differences in their digital boundaries. Note that three polygons have been given the same total population based on the census tract data. and area values will be inaccurate after you perform an intersection. you might need to create a map layer of streets for the area within a single police district but your street centerline file covers the entire city.Clip Clipping allows you to turn one shapefile into a cookie-cutter in order to cut out part of a larger shapefile. If you intersect a line and polygon layers. 7 | C r e a t i n g n e w g e o g r a p H i C f i l e s 93 . You can leave “Cluster Tolerance’ at 0. Using a street file that is clipped by the police district boundaries will allow you to work with a smaller and more manageable file that looks neater.
and area if you need these variables.” Select the input features. Be sure to recalculate length. you can find the “Union” function under “Analysis Tools” and “Overlay.” If you want to change this or the location of the new file. From ArcToolbox. but rather than clipping the resulting shapefile to include only the area covered by both. 2 . perimeter.Union Union is similar to intersection in that it fuses the boundaries of two layers together. 94 H i l l i e r | U s i n g a r C v i e w 9 . the shapefiles created by a union will most likely have some attribute values that no longer make sense. As with shapefiles created through intersections. The default name for the new shapefile will be the first input feature name plus “_Union. it creates a new shapefile that covers the combined extent of the layers. click on the folder to the right.
Be sure that your new shapefile is listed as the Target and that “Create New Features” is selected from the Task menu. open ArcMap and add your new shapefile. this process involved tracing a paper map on a digitizing tablet and then assigning real world coordinates to certain parts (like georectifying). professionals will still use this approach. The Intersection tool places a point where two lines would 8 | d i g i t i z i n g 95 .2 has on-screen digitizing tools that allow you to create new shapefiles without additional hardware or software. Start an edit session: from the Editor menu in the Editor toolbar. You have five choices: The Create New Feature tool allows you to draw points. Next. When you switch to the Layout View.” and indicate which directory contains the shapefile (shell) you just created. In some cases. Next. choose “Start Edit Session. from the View menu. go to Layout View. along with other map layers that may help you draw your new features. lines.” click on the icon at the bottom of your map display that looks like a piece of paper (next to the globe icon) or. To switch to “Layout View. or polygons.8 | Digitizing Most of the time you will use shapefiles that someone else created. you are in “Data View” and use the Tools toolbar to navigate your map. you need to choose a drawing tool. Digitizing is the process of drawing or tracing map features to create a new geographic file. Creating New Shapefiles When you open ArcMap. Using existing shapefiles saves time and generally results in more accurate map layers. The Arc tool allows you to create lines that are curved (rather than just a bunch of short line segments that look like a curve). Before on-screen digitizing was available. The Distance-Distance tool will place a point at one of the locations where two circles intersect. you have access to a different range of tools and use the Layout toolbar to navigate. But ArcView 9. But if you need a line or polygon file that doesn’t exist—such as a boundary for your study area—you will need to create it yourself.
clicking at each vertex to create a new vertex in your shapefile. “Options. vertices will work well. If you use a street centerline file as your guide. To create the most accurate line. Snapping to an Existing Feature It is nearly impossible to draw features that match an existing layer just by looking at it.cross if they continued far enough. 96 H i l l i e r | U s i n g a r C v i e w 9 . a new polygon feature was drawn that follows four streets. choose “Snapping. Use the delete tool to start over. In the example at left. from the Editor menu choose “Stop Editing” and save edits. To save your new feature. 2 .” and the “General” tab. The Create New Features tool is the most basic and allows you to draw new map features. You can avoid this problem by “snapping” your new lines to an existing shapefile. You can change the snapping “tolerance”—the distance from the existing shapefile you can be and still snap to it—from the Editor menu. From the Editor menu of the Editor toolbar. The result is map layers that look sloppy and can negatively impact the result of your analyses. your cursor will be pulled toward the vertices of the shapefile you are trying to trace. The Trace tool creates features that follow existing map features. move your cursor slowly over the existing shapefile. Click to create a new vertex and double click to finish. Try drawing your new features using different combinations of layers and vertices and/or edges. Use the undo tool to remove the last vertex. The map units reflect the units you identified in the Data Frame properties (General tab). go to Start Editing and indicate which directory contains the shapefile (shell) to which you want to add map features. Now when you start to draw your new features using the Create New Features tool. you can identify the layer(s) to which you want to snap your new features. From the Editor menu.” In the top of the dialog box.
add a census block layer to ArcMap. you may want to create a map of health districts. and add it to your map. Using the snapping tool. even when you zoom in close. Select the blocks within the area of interest. If you are not happy with your results. For example. If the districts are based on census tracts. To start.Digitizing using the Merge Tool The tools in ArcMap for dissolving boundaries between features provide another approach to digitizing. create a new shapefile based on these selected blocks (right click on it. click on the map feature with the Edit tool and hit Delete (you can do this even after saving edits to the shapefile. This may give you less control over the shape of new map features. 8 | d i g i t i z i n g 97 . but it provides an easier way of creating new shapefiles that line up with existing shapefiles. you should be able to create new features that line up with existing shapefiles. you can use a shapefile of census tracts to build your new district file. In order to create shapefiles using the dissolve tools. as long as you start an Edit Session). go to “Data” and “Export Data”). A census block file may prove the most helpful. you need to have a shapefile that can serve as building blocks for your new file.
If your new shapefile only needs to include this single map feature.Using the Select Features tool. You can select multiple features by holding down the shift key. go to Data and Export Data. you can right click on the block shapefile (with the new feature still selected). you may need to repeat the process of dissolving boundaries so that all census blocks become part of a new map feature. then from the Editor menu choose “merge. To dissolve the boundaries between the blocks. 2 . highlight the blocks that cover just the area you want your new map layer to cover. You can also draw a box around the area containing the individual features (this is faster). 98 H i l l i e r | U s i n g a r C v i e w 9 . start an edit session.” Stop editing and save edits to finish. Be sure that the Export drop down menu indicates that only selected features will be included. Alternatively.
Hit “Esc” to stop. where the names of your map layers will appear.9 | working with 3D 3D Models of Vector Data 3D modeling happens in ArcScene rather than ArcMap. looking above or below them and from any angle. you can pan your map layers (move them around without zoom in or out or tilting them). Vector polygons layers will draw as solid fill colors without any outlines. You add map layers into ArcScene just like ArcMap. Click on the “Extrusion” tab. It is even easier in ArcScene to loose track of where you are than it is in ArcMap. ArcScene is a separate application (. then ArcScene). Most of the buttons on the tools toolbar for navigating your map layers are the same in ArcScene as ArcMap. ArcGIS. It is possible to make points and lines 3D. double click on the map layer. such as when extruding streets and sidewalks in an impervious surface layer. If you hold both buttons down. This makes sense in some situations. and a big space to the right where your map layers will draw. Click on the full extent button (globe) to bring your map layers back.” Don’t worry if your map layers look funny when you first add them. Points and lines will look more similar to the way they draw in ArcMap. Once open. but a few are new.exe file) that you can launch from the Start Menu (Programs. The fly tool allows you to swoop in and around your model (caution: this may cause motion sickness). but some are new. In order to make your polygons 3D. it looks similar to ArcMap with a table of contents in the left. Here you can enter a constant value under “Extrusion Value or Expression” in order to make the entire layer the same height. you can spin and twist your map layers. The zoom in/out button allows you to zoom in and out continuously (like the continuous zoom tool in ArcMap). Most of the tabs under “Layer Properties” are the same as ArcMap. When you hold down the right mouse button. you will be able to zoom in and out continuously. “Add Data. The navigate button is the most useful. 9 | w o r k i n g w i t H 3 d 99 . but polygons work better. If you click the left mouse button. with the “Add Data” button or from the File menu.
You can use attributes other than height or elevation as the basis of the extrusion. you can extrude the polygons to reflect this. 2 . 100 H i l l i e r | U s i n g a r C v i e w 9 . if you have a height variable. For example. you can use the extrusion option to make buildings different heights and then use the symbology options to use different colors to show which properties are vacant.More often. You may need to adjust the formula later to make your relative heights work. You can use different variables for the basis of your extrusion and symbology. For example. Now your buildings should be different heights. For example. you will want to extrude the polygons based on an attribute. use the options under the Symbology tab (use this just the way you do in ArcMap) to make different heights different colors (graduated color map based on height variable). Click “OK” and then click “OK” again. but don’t worry too much at this point. In order to see the differences in the height more clearly. Click on the little calculator to the right of the “Extrusion value or expression” box and use the “Expression Builder” to create a formula for the height of the building. especially when you are extruding based on height or elevation. you can extrude neighborhoods based on the amount of crime.
Imagine that your scene is sitting on top of a lazy susan and you are just giving it a push in the right direction. From the Illumination tab. You may want to exclude all 0 raster values (click on classify. 9 | w o r k i n g w i t H 3 d 101 . If you are asked about building pyramids. 3D Models for Raster Data Raster data makes for great 3D models in ArcScene. you can change the height and direction of the sun to adjust the lighting in your 3D scene.” This means that the values stored in your raster layer will be used as the basis for the layer’s height. you can change the background color (black looks pretty cool). If you put a check mark in the “Enable Animated Rotation” box.” From the General tab. double click on the word “Scene Properties” at the top of your table of contents or go to the View menu and “Scene Properties. Then from the “Symbology” tab.” Don’t worry if your map layer looks funny when you add it. Click on “calculate extent” for ArcScene’s suggestion for how much you should exaggerate the vertical extent. say “yes. Rotate your scene with the navigate button. you can make your 3D scene spin around continuously.Scene Properties To access scene properties. From the “Layer Properties” click on the “Base Heights” tab. switch to a classified map and symbolize your map using one of the color ramps. then exclusion and type in “0”) and add extra classes so that the color ramp shows more gradual differences in value. Add your raster layer to ArcScene just as you do vector layers. then let go of the mouse button while the scene is still moving. Click the radio button next to “obtain heights for layer from surface. This is especially helpful when your layers look too flat or way too tall after extrusion. You can also change the vertical exaggeration. Hit “Esc” to stop the animation.
You may need to exaggerate the differences in your values to create a 3D model. From Scene properties, go to the “general” tab and click on “Calculate from Extent” next to “Vertical Exaggeration.” If you do, you may wish to report this exaggeration factor when you create maps out of ArcScene.
Animating 3D Scenes
To animate your 3D scene, you need the Animation Toolbar to be visible (“View” menu to toolbars, then “Animation”). The animation will be based on a series of snapshots of your 3D scene. Use the navigate tool to create the first perspective. Click on the camera button once (or use “Ctrl” + “A”). Use the navigate tool to choose your next perspective, then click on the camera. When you have created all your images, open the animation tools (using the button at the far right of animation toolbar). Click on the play button to view your animation. You can adjust the length (from options button) and speed (from Animation menu, Animation Manager) of your animation.
Saving 3D Scenes
You can save your 3D scene in the same way you save a map document in ArcMap. Instead of an .mxd file, you will create an .sxd file. Since these behave in the same way as .mxd files, you need to remember to keep the .sxd file with the shapefiles or raster layers upon which the 3D scene is built. To export an image from ArcScene as a 2D image, go to the “File menu” and “Export scene” and “2D.” You can also save an animation as a video file.
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10 | AnimAting time SerieS DAtA
ArcView includes two tools for representing time series data--the Animation Toolbar and the Tracking Analyst. Both require that each record in your shapefile is “time-stamped” meaning that one of the attributes includes a date. This could be in the format of seconds:minutes:hours such as the data generated by GPS devices or simply a year associated with census data. Tracking Analyst works best with GPS data while the Animation Toolbar works well with area data that are part of a time series and point data that have start and end dates. Under “Start Time,” choose the variable that includes the opening date, then choose the format. If you have an End Time, fill in those fields the same way. Then click “Create.” Click on the button the far right side of the Animation toolbar to access the animation controls. Press the “Play” button. Your points should begin appearing and disappearing. If you checked the box “Show time in display,” the year will flash in the left corner with the points.
Make the animation toolbar active from the View menu, Toolbars, then Animation. Add in the shapefile that you want to animate, for example, a point shapefile with all the theaters opened between 1880 and 2009. The attribute table must include a data field of some sort. In this example, there is a year associated with the opening and closing of each theater.
You can also animate areal (polygon) data such as US census data, although this involves some considerable reformatting to work. In order to animate, you need to have a separate row for each record (polygon, such as a census tract) for each time period. Take a look at the tables on the next page. The first one shows how time series data is normally included in an attribute table. In order to symbolFrom the Animation menu on the Animation toolbar, choose “Create Time Layer Animation.” Choose your shapefile in the first dropbox menu. ize the data to show the change over time, you would need to create a different map for each time period: 1993-1195, 1994-1996, etc (these are three-year rolling averages for state-wide rate of diabetes).
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Make the Animation toolbar visible. Before you can view the animation, you must symbolize your polygon shapefile. The map that appears will be for the first data point. From the Animation menu, choose “Create Time Layer Animation.” Under “Start Time,” choose the field with the date--in this case, Year. Click “Create.” Click the botton on the far right of the animation toolbar to launch the animation controls. Click the “Play” button.
In order for this polygon shapefile to work with the Animation toolbar, you must create a new record (representing a state) for each time period. You can do this using the Merge toolbar. In the end, your table should look like this:
Make the Animation toolbar visible. Before you can view the animation, you must symbolize your polygon shapefile. The map that appears will be for the first data point. From the Animation menu, choose “Create Time Layer Animation.” Under “Start Time,” choose the field with the date--in this case, Year. Click “Create.” Click the botton on the far right of the animation toolbar to launch the animation controls. Click the “Play” button. Click on “Options” from the Animation controls to change the speed of the animation. You can also create a video. From the Animation menu, choose “Export to Video.”
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go to “Toolbards” and then “Tracking Analyst.” 105 . click on the browse button to locate your shapefile. Then click “Finish.” On the next screen. choose the variable that includes your time field. go to “Extensions” and make sure there is a check mark next to Tracking Analyst). Be sure the Tracking Analyst Extension is turned on (from the Tools menu.Tracking Analyst Tracking Analyst is ideal for working with data collected with a GPS. Click on the “Add Temporal Data” button on the Tracking Analyst toolbar (yellow dot with a + in the middle). you need to indicate the format of your time field. Click “Next. From the next drop-down window. Next. Make the Tracking Analyst toolbar visible (from the View menu. Add your point shapefile. you can select the first radio button.” You should now see an Event theme in your table of contents. Look at the “Sample value” at the top and adjust the data accordingly. If your shapefile includes the time attribute.
From the Temporal tab. Be sure to make the dots small (2pt) and black and make the event symbol bold (such as a big red 106 . consider your two options for displaying the events. Double-click on your Events theme. for example) and then fine-tune the playback rate with the Slower-Faster bar. Push play. The second option works well if you have the original point shapefile (not the event theme). Click on “Options” to adjust the playback rate (1 second per hour.Click on the white “Playback Manger” button. You can change some of the symbology to make it easier to see the movement of the points.
This Cartogram script requires that your data be in the form of a Geodatabase. In the third dropdown.com/details.” From the cartogram folder. You can convert a shapefile to a personal geodatabase using tools in ArcCatalog. 107 . which take the form of Access databases and can incorporate multiple shapefiles. Give your cartogram a name and click “Save. navigate to your geodatabase.” In the first dropdown menu. but in recent years. From ArcToolbox. If you have trouble. it is probably because you do not have permission to add new programs to your computer. To add the cartogram script. In the second.” Click OK. The best cartograms are hand-drawn. You should see it listed in your ArcToolbox favorites.esri. The Cartogram script written by Tom Gross for ArcGIS based on the methodology developed by Mark Newman and Michael Gastner at the University of Michigan works quite well and is available for free download at http://arcscripts. automated computer routines for reshaping maps have become better and better.asp?dbid=15638 Cartograms work with areal (polygon) data. click on the folder on the right. Put a check mark in “Copy the Original Polygon Features table to the Output Cartogram Features.11 | CArtogrAmS The cartogram tool will only work with non-zero and positive attribute values. Right click in an empty area and go to “add toolbox.” Leave the remaining dropdown menus blank or leave the default values if they appear. so be sure to recode your data as necessary. launch ArcToolbox (click on the red toolbox at the top of the screen). choose the attribute that will be the basis for the cartogram. double click “Create a cartogram. add the cartogram toolbox. Cartograms are the quintessential “un-GIS” map in that they deliberately distort area in order to better represent some attribute value. choose your map layer.
Graduated colors will likely be the best choice. both the county and state shapefiles were distorted using the cartogram tool so that it is easier to connect locations on the cartogram to the original map of the United States.Symbolize your resulting cartogram by double-clicking on the new shapefile and going to the symbology tab. In the example shown to the right (resizing counties based on votes for President Obama in the 2008 election. 108 .
Spaces in names of variables? Long name? On harddrive. I can’t join my attribute table.. Make sure both are formatted as string (left justified) or number (right justified).. At the bottom of the table of contents.. then choose “join. add back in.12 | troubleShooting I can’t save my files. correct this in Excel. then project the data. Export the map again. I just get 0 and 1 when I’m trying to calculate a percent. I made a change.. Refresh the graphics (arrows in a circle next to map view and layout view buttons). I can’t open the attribute table on my shapefile after the join. Are you starting with the shapefile? Be sure to right click on the shapefile you are joining your data to. I can’t move my layers up and down in the table of contents. PowerPoint or other file? You may have skewed it here. Delete the column (right click on column name.. Might work. export.. Are you dividing by zero? Sort the column with your denominator to look for zeros. re-save. Resize only from the corners. My map looks skewed.. Are there spaces in the names of any of your variables? If so. Sort them both ascending to descending to make sure they are the same. Did you export the map in import it into MS Word. be sure to do this in ArcCatalog)... delete) and create a new 109 . not the sides (resizing from the sides squishes the map).. close and re-try. I can’t see my table in the table of contents.. If you see longitude/latitude coordinates.. Is it open anywhere else (like in Excel)? If so. I get an error message when I calculate values... that’s the problem.. You probably formatted your column as a short integer rather than double. Do the units show up but not make sense? For example.. Be sure to define. switch the selection so that all non-zero rows as highlighted.. does it show that Center City Philadelphia is 0. then try your calculation again... Start over with your original map layer and work through the projection steps again. My scale bar isn’t right.” Have you identified an identical join field in both tables? Open both tables up. click on the display tab. click on the source tab. Have you run out of room on your drive? Try deleting some old files (if you are deleting map layers. Right click. Highlight every row with a zero. Count the number of digits. At the bottom of the table of contents.5 miles tall or 30 miles wide? Your projection was probably defined incorrectly.. Are your data projected? Check the coordinates in the bottom right of your map in the map view.. Are the units “unknown”? You need to define the projection for one or more of your map layers. data. and try again. while resizing.. but I don’t see it on the screen. save under new name. change the location where you are trying to save the file. Are you saving to a write-able drive (you can’t save to a cd)? If so. change name of file. I can’t add/open my table to ArcView. try again.
Ask for help. Don’t worry. re-start and try again. Still stuck? Close ArcView. pretty much everyone does at some point (or at least they should). Try a new computer somewhere else (different lab).variable formatted as double. then try your calculation again. 110 .
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