Dear Alexey, dear James,
Thank you for your kind reply. I have tried both your suggestions but I cannot seem to get rid of the high errors (see picture 1 attached). Completely deleting all markers, deselecting the DJI cameras, updating and optimizing, does lower the camera errors somewhat but they are still +10m and I lost all my markers in the process (see picture 2).
Just to clarify: none of the markers have measured/correct coordinates. I did not have a total station for data capture and I only manually added markers to be able to combine several chunks (tie points gave me bad results). The coordinates are estimated by Agisoft, I presume based on the GPS info baked into the DJI cameras, which I didn't turn off at the time when adding the markers.
In short, I would like to be able to do the following with low errors:
1. align/merge different chunks based on markers;
2. create a scale bar for two of my manually added markers to be able to scale the model as best as possible without measured coordinates (I manually measured the distance between several markers with a tape measure on the real-life heritage asset);
3. I do not care for the coordinate system, as long as the model is correctly aligned and scaled according to the distance I manually measured.
Do you know how I can best achieve this without having huge errors?
Should I have deselected the DJI camera coordinates from the very beginning before adding my markers? Should all cameras (also the iPhone and DSLR without GPS info) and markers be in WGS84 before aligning? Should I set the camera accuracy in the Reference Settings to a lower/higher value?
So again, what I would ideally need is a model consisting of multiple marker-based aligned chunks, where the camera locations are estimated within an acceptable error (m) and scaled according to a scale bar on the model (which I do not know the coordinates of, only the tape-measure distance between two points).
Thanks a lot for helping me out!