CloudCompare forum

Hi and thanks for creating this great software.

I wanted to compare a point cloud based on an aerial laser scan with a terrestrial scan in the same area.
The point cloud based on the aerial scan was relatively low point density with 2 points per m2, which was used as the reference cloud.
The point cloud based on the terrestrial scan mean distance is approximately 4 cm below, which is because of GPS adjustments.
Can anyone explain why the standard deviation so high?

Well, many factors can explain the standard deviation, but it's generally mostly the density (but it seems you have used a mesh as reference so it should be ok) and the noise (which depends itself on a lot of factors). Moroever considering that the reference density is low, you probably miss a lot of small features which may be present in the higher density scan.

You can visualize the distances on your compared cloud: is it randomly distributed or do you observe patterns?