Lastools tools processing for and Potree UI

[Hong Tran]

Hi guys, 

I am trying to develop an integration between lastools tools with potree (http://potree.org/). So essentially building something to allow users to access to the lastools features via a potree UI. 

My plan is to;

1. Build UI for lastools in combination with a potree UI
2. Use Lastools to filter, clean, noise, thin, duplicate
3. Display on potree after every process

I have this working however when I get to large point clouds (>3GB), it takes some considerable time to convert from las to potree (laspublish). 

Let me know what you guys think? I see that PDAL and Entwine can do this also.

thanks

Hong Tran

[Martin Isenburg]

Hello,

the operations "filter, clean, noise, thin, duplicate" do not change 95% of the point. Almost all stays the same: xyz, intensity, scan angle, source ID, return numbering, GPS time, RGB color, ... The only thing that tends to change are "classification" and "flags" and maybe the additional "is deleted now" flag used in LASlib. Recompiling the entire Potree (which is done entirely based on XYZ) seems very wasteful. Integrating some form of LASlayers concept with Potree would be cool where you simply apply a small (temporary) LAY file to each of the LAZ files that make up the Potree at the moment and that LAY file only contains the changes in classification, flags, and deletion status for each point. 

Once you happy with the classification and flagging there could also be a "flatten" operation that then takes the original LAZ files and the LAY files and produces a new set of LAZ files.

You should be able to realize this completely outside of Potree and laspublish by operating directly on the folder structure that Potree creates. This starts with the folder called "r":

https://www.cs.unc.edu/~isenburg/lastools/Tikal/pointclouds/tikal/data/r/ 
https://www.cs.unc.edu/~isenburg/lastools/Tikal/pointclouds/tikal/data/r/02620/

As long as you just modify each LAZ file without changing any name and without rebalancing the tree, this may work surprisingly efficient if you manage to implement the external updates of classification and flags well. Matching points based on unique x,y,z coordinates plus intensity and point source ID should give a sufficienly unique way to transfer classifications and flags from the latest LAStools processed point cloud to the current LAZ files in the "r" directory structure.

Regards.

Martin 

  

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[Hong Tran]

Thank you Martin! 

I will give it a go soon and see what I can come up with! I agree, it is very wasteful to publish after every lastools process... 

Thanks for the heads up on the r folders, just need to investigate the r folder structure..

Hong

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[vaibhav kumar]

Hi Hong,

I am Vaibhav. I am a beginner I plan to work in a similar area. I want to use features of lastools such as to classify the point cloud and to use pottree to display it. Can you help me with this? Further, is it possible to run lastools from potree webUI.

Regards,

Vaibhav

[Hong]

Hi Vaibhav

 

Good to see your interest in the subject! I would start downloading the free lastools and reading the readme files...

 

There is also some great examples in your Lastools install folder ...\LAStools\example_batch_scripts\..

 

Regards

 

Hong

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