I am having problems to get accurate elevation data from a DEM generated in ortho mapping. I am using GCPs, and the elevation data values in the DEM are way different than the GCPs. I followed all the steps in the official documentation and I can not identify the problem. Any of you guys had the same problem? Please help!
What GPS did you use to obtain the z values of your GCPs? If you used a normal GPS (not a differential GPS), your elevation data might be off by a magnitude of 30m or more. Also, what imagery are you using (drone, satellite)?
To produce a DTM in ArcGIS you need to provide your own DTM. If you done have one, ArcGIS provides you with their elevation data.
Did you try and produce your DEM while leaving your GCP elevation data as "unknown" and compare with the results you have?