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Noise on .las files

Posted: Sat Nov 19, 2022 1:23 am
by ayush
Hi, I am trying to open UAV generated dense point cloud in CC but getting a lot of noise at the z-axis. If I use top and bottom-facing icons for my point cloud, it looks fine, but as I moved to the other directions, it scattered. I wonder if there is something wrong with what I am doing.

Re: Noise on .las files

Posted: Sat Nov 19, 2022 11:37 am
by daniel
Well, there are 2 options: either the cloud is noisy, or you have kept the large coordinates (if any) which is generally a bad idea as OpenGL can't properly display them (hence it generally causes a noisy display).

Re: Noise on .las files

Posted: Sat Nov 19, 2022 8:12 pm
by ayush
Thank you, Daniel!
But still, I am not able to solve the problem. I wanted to share more insights for a better understanding. The first image is the top angle for the .las data, where the second is scattering; my concern is also about the zoom-in level. Can you suggest any document or video I can watch for this?

Re: Noise on .las files

Posted: Mon Nov 21, 2022 8:32 am
by daniel
The scale of the cloud seems indeed very small... Where does it come from?

Would you be able to share it with me maybe? (admin [at] cloudcompare.org)

Re: Noise on .las files

Posted: Mon Nov 21, 2022 7:41 pm
by ayush
daniel wrote: Mon Nov 21, 2022 8:32 am The scale of the cloud seems indeed very small... Where does it come from?
It came from the Drone with the Multispectral sensor dense point cloud.

Would you be able to share it with me maybe? (admin [at] cloudcompare.org)
I did share data with admin@cloudcomare.org; I hope you can address the query.

Re: Noise on .las files

Posted: Tue Nov 22, 2022 9:37 pm
by daniel
Thanks. I believe the issue is simply that the cloud has geographical coordinates (with X and Y being angles) and not cartesian coordinates (all the same units). CC doesn't manage this mix of very small angles values for X and Y, and large coordinates for Z (relatively).