CloudCompare using the Swisstopo LAS-FIles, stange behaviour

[tgdbepe4]

First of all Lidar data of Switzerland are freely available to everybody, https://www.swisstopo.admin.ch/en/geoda ... ace3d.html.

Now I have a problem with the “intensity” in CloudCompare. I used the Sample Data, https://www.swisstopo.admin.ch/en/geoda ... usterdaten and opened the las files. When loading I used Accept all twice and the data is loaded well. But when selecting “Intensity” instead of “PointSourceID” the Display range use the maximum “displayed” and “saturation” value of 65534 and the nothing is seeing on the data rectangle.Manipulation these values to smaller values shows the more but the histogram is still not looking well.

Any idea what could be wrong?

Kind regards and many thank for an answer.

Peter

[daniel]

If CloudCompare shows in the scalar field properties a 'max displayed' value of 65534, this means that there's indeed such a value in the data. And that's theoretically possible since LAS specifications expect intensities to be coded between 0 and 65535 (16 bits).

Obviously, in this case, it looks more like outliers. You can see some white points here and there in the cloud with intensities above 65500:

intensity_outliers.JPG (307.72 KiB) Viewed 900 times

You have 2 choices:

1) the simplest: simply reduce the 'max saturation' value to 255

max_saturation.JPG (206.03 KiB) Viewed 900 times

2) Remove the points with high intensity with the 'Edit > Scalar fields > Filter by value' tool once the 'Intensity' scalar field is active

[daniel]

And to be clear: the issue is with the original data ;)

[tgdbepe4]

Thanks for the message. I had the same assumption. I like to derive from the data DHM/DOM Altitude data. But this is disturbed by these wrong Z values. Is it a way to cut or delete these points?

[daniel]

If you are referring to the wrong 'intensity' values, then yes, just use 'Edit > Scalar fields > Filter by value'

If you have also wrong 'Z' coordinates, then you can convert the coordinates to a scalar field first and do the same (with Edit > Scalar fields > Export coordinate(s) to SF(s)').

[tgdbepe4]

I tried but creation a hillshade or contour fails

[tgdbepe4]

it is working now. I user a detailed grid value! Sorry