build georeferenced orthophoto with only 4 ground control points as gps?

[booteer]

I have a set of photos in which the flight log was lost. None of the photos are georeferenced. However, I have known RTK GPS ground control points in the corners of the area. By identifying markers in my photos, I have been able to 100% align the photos in correct spatial orientation. I would like to build an orthomosaic using WGS84 so that I can manipulate in ArcGIS, but the only option I'm given is local coordinates (in m, ft. or ftUS)

Is it possible to build orthomosaic using WGS84 with this data set? If so how would I go about that? Thanks for any assistance!

[Alexey Pasumansky]

Hello booteer,

In PhotoScan you can georeference the model using either camera locations (the positions where from the photos were taken) or the points in scene (on the ground, for example).

The coordinates of such reference points should be input to the Reference pane and the corresponding instances should be enabled (also the cameras should be aligned and the markers should have at least two projections on the aligned cameras).

[SAV]

Hi booteer,

You need to choose the correct coordinate system for your ground control points. If you do so, then you can export your orthomosaic in any desired coordinate reference system, such as WGS84.

Regards,
SAV