CloudCompare forum

Hi!

I am trying to merge ALS and MLS using point cloud. ALS is from L1 so it has RTK and it is my reference. when i get the global shift prompt i always say yes to all. now, when i load my MLS which does not have coordinates i will untick the preserve global shift as i want it to be georeferenced with the ALS data. everything is fine. until I aligned the MLS to ALS. every time i shift the MLS to align it with the ALS it will do this:
I tried fine register, point picking and translating it will still have it. The worst it when i export it it will have the same problem.

not sure what to do as i've tried so many method. I've been playing around with the global shift to see what works but it will do it again.

Please help as im stuck with this.

So on the first captures, there's clearly something wrong as you are translating the points from a local coordinate system with small coordinates to a CS with large ones (hence causing the accuracy loss and the display issue).

You should load these points without any shift, and then only apply a (virtual) shift to this cloud so that they end in the same global shift as your other cloud. Either via the registration tools, or via the 'Edit > Edit Global Shift & Scale' menu entry.

Thanks Daniel!

Yes. you are correct. I had to load the MLS point cloud with "Automatic" so it will not place it far away from the reference PC.