I have done a fair bit of reading and research with no success. I flew a map at 150ft, and shot 5 GCP’s spread throughout the map. Looks like the GCP marker is close to 150ft from the surface. Is it possible that the geolocation of the photos are 150ft off? If so, how can I fix this problem?
I used a phantom 3 pro to shoot the images.
Riley,
That is normal, as the Phantom 3 (and most UAV’s) will use the flight altitude above ground for the elevation data to geotag each photo in the EXIF header.
After you mark your GCP’s on the photos and reoptimize, the 3D model will be shifted to match your GCP’s.
Hello Riley,
Do you know what heights your GCP’s are? Are they geoid heights or ellipsoid heights? Since UAS use GPS lat/long/ellipsoid height measurements, your photos will be collected with this information. If your GCP’s have been collected with geoid heights there will be a difference. Depending on where you are in the world the difference can vary, maybe even up to 150ft.
this happened to me once because my elevation data was in meters and after i converted it to feet the GCP was right on the ground where it was supposed to be hope this helps.