Adding ground control points to raster in ArcGIS Pro desktop

Question

I'm trying to add ground control points to an orthomosaic raster created in ArcGIS Pro desktop.  The orthomosaic was created with drone images taken with a non-ESRI mission app (Map Pilot Pro).  The orthomosaic has come out perfect, but I did six GCPs during the mission with the GCPs being targets on the site surface, which were then accurately located using a GPS/GNSS PPK device.  The targets are visible in the finished orthomosaic, and I've tried to use the Manage GCPs tool to accurately locate the GCPs for a final adjustment of the orthomosaic.  I have created a .csv file of the GCP coordinates according to the instructions, and imported it to the GCP Manager window. I've looked for a tutorial for what should follow, which to me would be identifying the individual GCPs on the raster and linking them to the GCP in the .csv file, but I can't seem to work this out. Can anyone help?

Cheers, Bob

Anonymous User · Answer

If you have the GCP coordinates and their spatial reference, you can load them into ArcGIS as a point feature class. The orthomosaic is the "from", and the GCP point geometry is the "too" for georeferencing. Then you can use one of the georeferencing transforms to do the shift.

bobscarto · Answer

Hi, thanks for the suggestion, but I'm unclear on the process.  I can click on the GCP in the raster, but don't understand 'click on the corresponding vector point'? (I'm still on the ArcGIS learning curve).  I agree with your second point, which I'm trying to achieve.  Cheers, Bob

Anonymous User · Answer

Maybe I'm thinking about this too simply, but couldn't you just georeference the ortho to the GCPs and apply the transformation? E.g. click on the GCP in the raster and then click on the corresponding vector point?

I'm not familiar with the image processing software OP mentioned, but as far as I know it is better to incorporate GCPs during ortho processing, and not after. If the software is working as intended, the GCP transformation will be better fit than a shift after the fact.