Latitude and Longitude
Latitude is measured North or South of the equator (00°). There are up to 90 degree North of the equator and up to 90 degrees South of the equator. Lines of latitude are known as parallels of latitude.
Longitude is measured from the Greenwich Meridian (also known as the Prime Meridian). These can be up 180 degrees West of Greenwich or up to 180 degrees East of Greenwich. Lines of longitude are also known as meridians.
To accurately pinpoint our position the geographic coordinate reference is given as Latitude first then Longitude and the degree is broken down into minutes then tenths.
There are 60 minutes (shown with a ‘ sign ) in 1 degree (shown as ° sign). There are 10/10th in 1 minute and the tenths are denoted with the decimal point. For example:
The latitude number for degrees is only written with two digits whereas the longitude is three digits – think back – Latitude can only go North or South by 90 degrees, whereas Longitude can go east or west by 180 degrees. It is good practice to write it in this format as it avoids confusion if someone else is following on from your chart work.
The Latitude scale runs up and down the side of the chart
The Longitude scale runs across the top and the bottom of the chart.
For example if we had a GPS (Global Positioning Position) of 45°14’.5 N 006°17’.4 W