We're going to look at the application of drones to the Geo Cloud and their usefulness beyond entertaining your friends and terrifying your neighbors. Most people have experienced the fantastic photos and video that can be captured from the air using a drone. However, there are many practical applications useful for businesses in a variety of sectors, including civil engineering, architecture, construction, and forestry. High-quality data can be captured in an affordable way that is critical in the planning process or decision making. We'll look at several of these data types below.
Having a birds-eye view of things can be a valuable thing to have. Location-focused organizations and the public rely on imagery to understand the change in a city, a construction site, and vegetation health. A few benefits of using drones to capture this data are the resolution you can achieve and the frequency of capture. Traditional methods typically involved a plane flying over an area to get the job done. Many projects only require a small area to be photographed, and getting high-resolution imagery could be very expensive; a large area would have to be imaged for the aircraft method to be cost-effective.
With a lower training window and the low cost of drones on the market the barriers to entry have been lowered. Small areas can be captured more often and for cheaper since it doesn't require a large mobilization of resources to make it happen. Send a person out (a certified person of course) with a drone and go for it. That's an oversimplification but easier than rigging up an airplane with cameras, hiring a pilot, getting flight plans mapped out, and flying thousands of feet in the air. These more traditional methods still play an important role. It's infeasible to use a drone to capture imagery for an entire city. It could be more cost-effective but the time it would take and risk of the drone crashing is too high to attempt it. This problem is being addressed though. Go check out this hybrid gas-electric multicopter drone that can fly for five hours!
Digital Elevation Models and Hillshades
Elevation plays a crucial role in many verticals, especially civil engineering. Before any street is built or skyscraper raised up, it's critical to understand the topography of the project area. This forms the foundational data set that everything is built on top of. Digital elevation models, or DEMs, are a model of the surface of the earth that can be used to map water flow, detect movement in a hillside, and plan routes for trains. The USGS supports the National Elevation Dataset that is available for free and used by businesses and scientists around the world.
Hillshading is a technique to create relief maps and model the shape of the earth's surface. It is derived from the DEM and adds elevation context to maps. As you can see in the map above the information is more valuable with the topographic surface layered with the DEM. This data is generated by using photogrammetry to calculate elevation. With some complicated math and accurate GPS, individual pixels can be assigned an elevation value by referencing the height of the drone with the distance to the ground. One of the more exciting developments in this area is mounting laser scanners to drones that can get millimeter accuracy of a surface. This could rapidly speed up the surveying process and reduce costs.
Contours are also derived from the DEM and show the change in elevation from one point to another. Locations of similar elevation are connected with a line to enable the detection of slops, pits, and peaks. Since drones can get high-resolution elevation data, contours can be generated at a resolution of about one or two feet. Keep in mind though that this method relies on photogrammetry and isn't accurate enough to replace surveying. Despite this, it can still play a role in initial planning and preparation for a civil engineering project.
Infrared data has enabled us to understand the impacts of our changing world better. From mapping global heat patterns to monitoring weather systems infrared can give us a different perspective than otherwise possible. There are many open sources for infrared data and has helped enable scientists and universities around the world to carry out critical research on various topics.
Photos & Video
We've all seen some creative videos out there that swoop in and out of previously unattainable locations. Video provides a different perspective than imagery and allows one to see the details of vertical structures. Inspecting infrastructure used to be difficult until drones came along. Instead of deploying a large crane or a helicopter, you can let a machine take all the risks to get the data you need.
Photos are also useful when inspecting infrastructure or showing places of beauty. Aerial images are easier to capture since you're not flying a route with a drone; it's more 'point and shoot'. The aerial perspective can capture amazing views of homes for real estate, cracks in a decaying building, and check on the condition of electric lines.
Drones can provide us with valuable information and a cost-effective means of acquiring that data. Not everyone should just buy a drone and start mapping anything and everything. There's a lot of privacy concerns and risk factors to be addressed. For example, flying a drone near buildings or trees can cause it to get tangled up and potentially fall on someone. Make sure you get certified, follow proper procedures, and obtain liability insurance. If this concerns you, don't worry. NASA is working an unmanned aircraft management system to track all the drones being flown around. The policy is finally catching up, and I think it will be for the benefit of all. Stay tuned as an article will be coming out soon with some of the data types above. I included a picture of the study location below. Let's just say it will involve hauling a drone ten miles into the desert, an abandoned train track, and revisiting one of the coolest places I've seen in Southern California!