I am merging multiple projects all with the same output coordinate system, and the same GCP coordinate system. However, after choosing all the projects, it gives me an error for each one saying the output coordinates are NOT the same. Please help!!
The coordinate system (both horizontal and vertical) of the images has to be the same. Note that a project with no geolocation can be merged with another project having image geolocation. The same applies to the GCPs and to the outputs.
You only mentioned the output coordinate system. Could you please check the others?
You will find more information about merging projects here: https://support.pix4d.com/hc/en-us/articles/202558529