Possible scale issue between point cloud and GCPs exported from QGIS

[dogad]

Hi Daniel,

First of thank you for your support and amazing tool.

I am trying to georeference a point cloud scanned with a mobile lidar system. When I import my scan (saying yes to global shift and scale) and check with the measurement tool, it shows 10 units one side, which makes sense since it is 10meters in real world. Then I am also importing 4 more points as ground control points (GCP)(tried it both long-lat elevation and XYZ(m)). When I check the distance, it is 0.000025. I tried to create a txt file and import same thing is happening. I also used QGIS to create the same 4 points from a base map and export them to open in CC. The same scaling issue is happening.

If I scale up GCPs and register the cloud, I am losing my georeference. I f I scale down my point cloud, it is distorting points so much, I can not see anything when I import it on QGIS.

I am not sure what I am missing, but any chance you can help?

[daniel]

So first, long-lat elevation cannot work with CloudCompare (because CC only handles cartesian coordinates).

But xyz should work. Then it depends of course of the units of the GCP coordinates (is it also in meters?).

Then, are you importing the 4 GCPs as a cloud (with some global shift applied) or do you input them directly in the Align tool?

Last, which version are you using?

[dogad]

Yes it is in meters.

I am importing 4 GCPs as clouds with a global shift applied. However, I import XYZ coordinates as a text file, just drag and drop.

I am using 2.13.2 Kharkiv.