Separating/Translating LAS point clouds

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sxb7983
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Joined: Mon Jun 27, 2016 6:08 pm

Separating/Translating LAS point clouds

Post by sxb7983 »

I am comparing frames of LiDAR data taken from a moving, airborne drone. Each frame is a file in LAS format. When I open more than one of these files in CloudCompare, the clouds overlap each other and are not translated correctly to properly display the area of ground that was. For instance, 2000 frames are all centered in the same place when they should be translated relative to each other. The files contain the necessary GPS data to do so.

This may be how CloudCompare loads files as a default; centering them all in the same place. However, I wish to find away to separate the clouds to their correct places in order to get an accurate model of the ground that was surveyed. Is there a simple function, tool, or way to do this in the CloudCompare software?
daniel
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Re: Separating/Translating LAS point clouds

Post by daniel »

Nope, CC uses the coordinates as they are stored in the file.

The only exception is when the coordinates are too big. In this case CC will display a dialog (Global Shift & Scale) that will suggest the user to move (temporarily) the scans to a local coordinate system. If the clouds are close to each other (or if they are all loaded at the same time), CC will apply the same translation to all clouds (so that they all fall in the same coordinate system). At export time the clouds are properly saved in their original coordinate system.

Here are some questions:
- what version of CC are you using?
- what do you mean by 'The files contain the necessary GPS data to do so'?

Don't hesitate to send me a few samples if you want me to investigate this issue (cloudcompare [at] danielgm.net)
Daniel, CloudCompare admin
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