Digital Elevation Maps are used for a multitude of purposes. Here in the lab we use DEMs to determine how and where water will flow. We also use DEMs to estimate rates of erosion and deposition along water boundaries. This can be useful for determining the success of restoration projects or deciding if a bank needs protective measures to prevent erosion.
When we can’t find data at the right resolution for a project we will collect data in the field using UAVs that allow for us to create high resolution DEMs. This is done by programming specific flight paths for drones and setting the points that we want to capture images at. We then use photogrammetry to create a point cloud from the data which we can then use to create a DEM. We have found that we can create DEMs will a cell size of a centimeter or smaller depending on the necessary resolution for the project.
We are currently working to compare DEMs from UAVs to DEMs created using Lidar, so that we can determine the error associated with UAV created DEMs.