GCPs not aligning - not understanding the effect of image resizing

Hello all, I did process a mission with different options. The output surprised me at first but I think I understand why.

First option - Fast orthophoto and no resizing. The GCPs lines up.


Second option - HQ and resizing of the images. The GCPs does not line up to the ground marker.


So marking the GCP images in the GCPi is done in full resolution which makes the pixel position wrong if you then resize the image in the process. This is not a statement, its more a question to you guys that undestand this better than myself.

So if this is correct, when running a process that include a GCP file you can never (?) resize your images or is there a way to do this?

Also, final question. When you download your results from your account at webodm.net. Is there any of knowing the option selected from the downloaded results. All tasks are deleted from the wedodm desktop were the process original have been made.

Hey @mattias :hand: you can use GCPs if you resize the images via WebODM (we resize the coordinates of the GCP file in the process). The marker might be off for other reasons (perhaps lesser model accuracy due to the lower resolution).

Currently we don’t save the processing options, but that’s a good suggestion for a feature. I’ve opened https://github.com/OpenDroneMap/ODM/issues/1062

1 Like