Aerial Lidar- Color points by classification

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mla757
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Joined: Mon Jul 02, 2012 1:00 pm

Aerial Lidar- Color points by classification

Post by mla757 »

Hello,

I am a student of Geoinformatics and testing the CloudCompare 2.4.6 software for the visualization of aerial LIDAR data on windows (32bits). In order to visualize the point according to their prior classification in ground/vegetation/buildings/etc. I search for a function in CloudCompare to do this. Is there any possibility? So far I tried out the different scalar tool but couldn't get the desired results yet. Thank you for your help and this very nice software!

greets,

Michel
daniel
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Re: Aerial Lidar- Color points by classification

Post by daniel »

Hi,

there's no particular classification algorithm in the actual version of CloudCompare. We'd be glad to get a plugin for doing such things ;)

AFAIK the only program which performs classification and which outputs files compatible with CloudCompare is the one developped by Dimitri Lague and Nicolas Brodu:
viewtopic.php?f=14&t=176

As I'm not a geologist myself, I can't help much.
Daniel, CloudCompare admin
mla757
Posts: 3
Joined: Mon Jul 02, 2012 1:00 pm

Re: Aerial Lidar- Color points by classification

Post by mla757 »

Hi Daniel,

thanks for your response.
In my case the classification of the file is already done with LAStools (also open source and very good) and stored as .las . Just for visualization in cloud compare I was looking for an option to color the points according to the classification spezification of the .las format. Because there are already much more sophisticated coloring options in cloud compare, I thought that the program had already included coloring the points according to the classification in the .las format.

edit: I found a way to display the different classes by saving points of each class seperately and then import it into cloud compare. Is better anyhow for the choice further visualization options by object.

greets,

Michel
daniel
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Re: Aerial Lidar- Color points by classification

Post by daniel »

Oh sorry, I didn't understand your question ;)

So of course it would be rather easy to load this classification as a scalar field (with different integer values for each class for example).

Can you send me a small example dataset?

Best,
Daniel, CloudCompare admin
daniel
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Re: Aerial Lidar- Color points by classification

Post by daniel »

There's a new version available to download (07-03-2012).

It imports the Classification field (and also the Intensity field by the way - if any) as scalar fields.

On the example dataset you sent me, it gives something like this:
Classification import
Classification import
cc_classification.jpg (285.72 KiB) Viewed 14161 times
You can quickly get an overlook of the values actually associated to points by displaying the scalar field histogram.
You can pick a point to ask for his associated value (SHIFT + left click on the point)
You can also segment out each class by using the 'Filter points by value' tool (either via the menu or the 'min/max' icon in the upper toolbar). Or you can play with the 'min and max' displayed values of the scalar field in the properties window (bottom left).

Hope it will be usefull,

P.S. : when dealing with such 'integer' scalar fields, you can set the displayed decimal precision to 0 (in the 'display' options) to avoid all the unnecessary zeros on screen
Daniel, CloudCompare admin
mla757
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Joined: Mon Jul 02, 2012 1:00 pm

Re: Aerial Lidar- Color points by classification

Post by mla757 »

Cool!

thank you much for this increadible fast update! This function makes it much easier and faster to view aerial LIDAR data.

greets,

Michel
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