Shift problems at saving

[gonzalezpij]

Hi Daniel

I detect an issue when saving LAZ (1.3 or 1.4) files, I'm editing (cropping, merging, cloning, and cropping) point clouds, and then I'm saving them.
Later on, when I open them I detect a wrong location. Then I tried to save it on LAZ (NO 1.3 or 1.4) and it's working properly

Thanks

[daniel]

Have you paid attention to the LAS Shift / Global Scale? (either at export time or import time).

This shift will be applied at loading time, and it might be different for different LAS files. Which will result in the clouds transferred in different coordinate systems when loaded in CloudCompare.

[gonzalezpij]

Thanks Daniel

I understand that is the source of the problem but I still don’t understand why saving on las isn’t a problem but it’s with las 1.3/1.4

[daniel]

I guess it's maybe because the PDAL filter and the LASlib filter don't manage the LAS SHIFT information the same way...

Which version of CC are you using by the way? (I believe we tried to make things consistent recently between the 2 filters, but maybe it's not full consistent yet).

[naamaR0660]

hi,
when I import points cloud in LAS format and then export the same file, the file which had exported has rounded values (coordinates or point number) while it wasn't like that in the beginning.
What can be done so the values wont be rounded?

[daniel]

Not sure to understand. Are you applying / accepting the 'Global Shift' suggested by CloudCompare at loading time? Is the suggested shift sufficient? (i.e. resulting coordinates are small enough so as to not loose accuracy).

[gonzalezpij]

Sorry for late reply, i got that problems are just coming on this way:

1. I open a file on las format
2. I manipulated (cut, sectioning...) on CC
3. I saved on format las 1.3


in this case the point cloud is saved with a wrong coordinates

[daniel]

Is CloudCompare suggesting you to apply a Global Shift at loading time? What are the coordinates of the points after loading? (you can hold SHIFT and left click on any point to spawn a label and read the coordinates).