After asking the Community about using Ground Control Points in ArcGIS, I have narrowed the problem down to (apparently) the format of the X,Y,Z data in the .csv file that is imported using the Import GCP file command under the Manage GCPs tab in Ortho Mapping. I have been using Decimal Degrees, not DMS, but they don't seem to be accepted by ArcGIS. I'm wondering whether there is a rule for the number of digits after the decimal point. I've even tried dropping the decimal point, but this doesn't work (and isn't accepted practice for GPS coordinates). The other problem was that creating the table in Excel meant that when it was saved as a .csv, it always appeared as a .txt file, with the X and Y accuracy columns missing. I finally ran the Excel file through Google Sheets to get an actual .csv file with all the data, but this still didn't work with Import GCP file. Anyone with any answers?
Cheers, Bob
