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 Photogrammetry - Point out of Tolerance

Jacob Foushee's profile image
Jacob Foushee posted 08-17-2023 05:51

I am processing a flight that we flew at 200AGL. After doing the relative and absolute adjustments, every image has an error flag saying the point is out of tolerance. Each point is between 103 to 121 feet out of the vertical tolerance. When I imported the ground control points and images, the flight surface that TBC generates was approximately 110 feet above my ground control points, but the surface was 200 feet below the the drone icons. The error values and the difference between ground control points and the flight surface seem related, but I do not know why the GCPs generate over 100 feet below the flight surface. After doing relative and absolute processing, the GCPs shifted to the flight surface, but every image has an error. Why does the flight surface generate above the ground control points before processing? How can I solve this issue? Thank you. 

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Christoph Heck's profile image
Christoph Heck posted 08-25-2023 03:26

Hello Jacob,

this is difficult to answer without having access to the data. It can have multiple reasons. E.g one of them is that some drone imagery include only a relative flying height information and not an absolute height. Depending on which information is available to the software during import this can lead to such an error.
Theoretically when the absolute adjustment is successful and the report does not show any problems, you can still proceed with processing the deliverables.


If you want us to take a closer look, please send the input data and coordinate system information to imaging_support@trimble.com. Me and the team will then take a closer look.

Best regards,

Christoph