Photogrammetry is the process of stitching multiple photos together to form a 2D map 3D model or structure. Terratest Aero uses UAV’s (drones) to take these images. This process has been proven to be both effective and efficient.
The UAV is programmed to fly a precise grid pattern, taking pictures with the downward facing camera. Each photo is georeferenced, enabling the computer software to stitch the overlapping photos into a 2D map and 3D model. Resolution can vary between 2-4cm per pixel depending on a few factors such as height, camera resolution and the percentage of overlap.
To increase the accuracy of the map / model, Ground Control Points (GCP’s) are used to place the data on a coordinate system for surveying. GCP’s are points marked out on the ground and then GPS surveyed. They are then brought into the software to be tied to the 2D map. Without GCP’s the GPS accuracy is similar to your smart phone, which is great for some research and environmental uses, however to achieve accurate data GCP’s are required.