How to classify a point cloud with 3 or more classes?

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JUB2
Posts: 2
Joined: Sun Jun 19, 2022 7:06 pm

How to classify a point cloud with 3 or more classes?

Post by JUB2 »

Hi

I’m having some trouble classifying a point cloud from a drone using the CANUPO plugin.

First of all, I get a quite good result following this video when I only have to classify ground and low vegetation: https://www.youtube.com/watch?v=8ryh_Qy ... ex=2&t=27s

My problem is that I have a point Clod where I want to make 4 classifications: Ground, Low vegetation, medium vegetation and high trees.

I’m using the latest version of CC where I can set the class of points inside the polyline using the # in the segment tool.

I create 4 classifications (Ground, Low vegetation, medium vegetation and high trees.) using the # in the segment tool.

After that I use the CANUPO Train Classifier, but here comes my problem: I can only choose two classes to make the classification (well that’s not quite right because I can choose all the classifications I have made, but the CANUPO plugin only handles to classes at the time). How do I make a classification of the point cloud which contains all 4 classes?

To summon up:

I can make a full classification when I only need to do 2 classifications in the point cloud.

I don’t know how to make the classification work when there is supposed to be 3, 4, 5 or more classifications in the point cloud.

Help much appreciated


Kind regards

Jacob
daniel
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Re: How to classify a point cloud with 3 or more classes?

Post by daniel »

So the 'train' option of Canupo doesn't work like this. You have to provide it with individual clouds of each type (ground / low vegetation / etc.). And then you can tell optionally the plugin to flag the points with a particular value (class label).

So you have to first create a classifier for ground / non ground. Then Another classifier for low vegetation / non low vegetation, etc. And then you have to apply them in a cascading way.

And what you did with the segmentation tool will just let you create the 'training' clouds more easily.
Daniel, CloudCompare admin
JUB2
Posts: 2
Joined: Sun Jun 19, 2022 7:06 pm

Re: How to classify a point cloud with 3 or more classes?

Post by JUB2 »

Hi Daniel

It was the part of doing it in steps I missed. I will try that.

Thank you for answering

Have a nice weekend

Jacob
bpearse
Posts: 2
Joined: Tue May 17, 2022 2:30 am

Re: How to classify a point cloud with 3 or more classes?

Post by bpearse »

Hi Jacob, I am wondering if you ever got this to work and if you were somehow able to validate your classifications (ie a confusion matrix)?
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