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Shifting the georeferenced Pointcloud

Added by Puschmann Philipp almost 3 years ago

Hello everyone,

I use georeferenced Point clouds, and Jan Hackenberg has figured out, that my Coordinate System is not very good for certain operations.
He told me that it would be usefull to shift the Pointcloud from 690000,5630000,420 (which is way to big) to a Center of 0,0,0.
I would use LASTools with the command las2las for shifting the pointcloud. The only problem is that I have limited Access to LASTools.

Is there any better Way to shift the Pointcloud? Maybe even in Simpletree or Computree?

Thanks for the answer
Philipp


Replies (6)

RE: Shifting the georeferenced Pointcloud - Added by Bauwens Sébastien almost 3 years ago

Hi,

CloudCompare does the job (open source software).

Sébastien

RE: Shifting the georeferenced Pointcloud - Added by Hackenberg Jan almost 3 years ago

Hello

the issue about my plugin is that it heavily relies on the point cloud library. PCL works with float and not with double precision. There is floating point issues in case of georeferenced data to be expected. I will
a) focus on a translation step
b) try to implement checks in the steps to give a warning dialogue in case somebody misses that issue.

As you also made a different reference between SimpleTree and Computree. We are working quite hard on a common release. Until now I discussed with Alexandre it is best to split up my plugin from the other nice plugins. As soon as we finished documentation and testing we hope to release a complete Computree (including my plugin of course).

Cloudcompare is anyway a nice program to have installed if you work with point clouds. You can do rendered screenshots with Lightning and Shading for reports/thesises/publications.

Jan

RE: Shifting the georeferenced Pointcloud - Added by de Lera Ana almost 3 years ago

Hello

I also had a similar problem with the z value (too big for stem detection method that only acept the interval -100,+100)
After asking Jan Hackenberg, I shift the z value easily in Cloudcompare and everything works perfect.

Ana

RE: Shifting the georeferenced Pointcloud - Added by Hackenberg Jan almost 3 years ago

Hello all

for giving SimpleTree Plugin (SimpleTree plugin + normal Computree common release is worked on) issues more visibility:

- SimpleTree needs input data centered around (0;0;0). Ana detected a bug here. I worked on a solution but shifted clouds still are an issue. Could not fix in the end and georeferenced clouds should not be used. Also real world height (can for example be estimated by FARO scanners as far as I know) is dangerous. Please shift for the moment with cloud compare, will post about Computree build in functionality soon.

- With too large plots (hecatre and above) the segmentation time seems to explode and become unacceptable. Working on it...

Jan

RE: Shifting the georeferenced Pointcloud - Added by Puschmann Philipp almost 3 years ago

Hey,

thanks for the answers. I can use now cloudcompare and I even figured out the shifting. I have only one problem:

The shifting is not permanent.

I looked everything up but after closing the session the coordinate system is resetted. I cant find any “save” button or something simelar. The only thing I found was in

Edit –> Edit global shift and scale

There I can theoretically reset the transformation to a new one but i couldnt save that either.

Tanks for help.

Philipp

RE: Shifting the georeferenced Pointcloud - Added by Hackenberg Jan almost 3 years ago

Hi Philip

I had the same problem two aweeks ago. Could not solve with CC. Computree also has a manual tool under points→transform→translate.
I hope I put also in my release. But you could also look in standard Computree Release.
You should write down the shift and if you want apply the shift back to all the detailed files as well as the coordinates in the plot file. If Alexandre
knows a solution automatic for your problem (I think there is a loop system for steps in CT Core) he might can help.

Jan

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