Feature Request: Additional Control Point Types

[Saijin-Naib]

I think it would be very helpful to have a concept within ODM of multiple types of control points.

Currently, we have the concept of 3D Ground Control Points (XYZ). I think a more expanded list would look like this:

1. Ground Control Point (XY)
   1A) For horizontal scaling/registration without high confidence in Z
2. Scale Constraint (XY/XZ/YZ)
   2A) To scale the point cloud in a scene given pairs of points with a known distance
3. Manual Tie Point (XY/XYZ)
   3A) Manually identified in-situ features
4. Check Point (XY/XYZ)
   4A) Used only for Report/verification, not for adjusting reconstruction

[pierotofy]

1. Might be a bug (nan should allow to not use elevation)

[Saijin-Naib]

I'm not sure where along the line the NaN failure came about, but it is a thing we've seen a few times recently(ish):
https://community.opendronemap.org/search?expanded=true&q=GCP%20NaN%20order%3Alatest

[kikislater]

For 2... Useful with dome/banana effect.
May be a workaround is possible:

• Running complete process
• Measure distance in potree
• Divide measured distance in potree by real measurement
• Add option in ODM to scale model
• Re-run process from beginning using new scale option and use scale value in pdal command. Scale is available in some pdal's writers

Reference: mapillary/OpenSfM#737