computing gradient from distances

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wrenRaming
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Joined: Thu May 28, 2020 5:50 pm

computing gradient from distances

Post by wrenRaming »

Hi,

Sorry if this is a naive question but I am a little confused about the output of gradient from a scalar field. Given the euclidean/distances option (let's say horizontal distance vs elevation), why would the gradient be capped at 1? Maybe I don't fully understand how the gradient is calculated for a point cloud but in the simplest scenario, it's just the ratio of the vertical distance to the horizontal right, so larger values are certainly possible. I have been working an example of sea-cliff on Hawai'i that I am almost certainly should have a higher gradient, but still, the gradient only ranges from 0 to 0.9, this is even true if I click no on the distances option. I attached the example below.


Cheers,
Wren
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daniel
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Re: computing gradient from distances

Post by daniel »

This 'euclidean distance' option only works if the scalar field is '3D euclidean distances' (due to the way they are computed on a point cloud, the gradient can't be bigger that one as you divide the difference of 3D distances by... the 3D distance between the points). But if your scalar field is not a 3D distance, then yes the gradient could be bigger than 1.

And anyway it's just a way to cap the scalar field, therefore if you don't say use this option, you'll get the uncapped version.
Daniel, CloudCompare admin
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