The only difference between the two tasks is that one has a gcp_file.txt. Docs says proj4 strings will work. Any suggestions are appreciated. I’m guessing I could just convert the GCPs to WGS84/latlon, but shouldn’t this work?
Converted to UTM last night, re-ran it, and it was completed this morning. But you can see that the GCPs are not exactly on the spot.
It detected that the area was WGS1984 UTM Zone 12, so I used that coord system for the GCPs. (Which were collected with a Trimble GeoXH.) Shouldn’t the GCP coords match even if they were off due to GPS inaccuracies? All of the points are off by a few feet. I rechecked the pixel locations for the images and all are correct. Would using an EPSG code yield better results?
Well, I guess technically it was in WGS84 from the beginning as it came straight off of the GPS receiver, right? So no datum conversion. I converted to State Plane the first time and used a proj4 string for that State Plane system, which didn’t work anyway. This time I used the string from the odm_georeferencing file created with no gcp file.
But even if it wasn’t correct, shouldn’t the ground marker in the ortho image match the point? It would be skewed/stretched elsewhere in the image, but they would be top of each other.
Interestingly, I reran it again with higher precisions on the offsets for the images (three decimals) and it was better. (I used a blank/empty ArcMap.) Thanks for your help.
I’ve ran another dataset (which I know has a correct gcp_file.txt) and that worked OK. Nothing stood out to me, except that odm_georef was unable to lock 3 GCPs with an error less than 1.5 meters (which seems a lot).
