Scale display in height ramp

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yankoch
Posts: 2
Joined: Wed Jul 13, 2011 10:06 pm

Scale display in height ramp

Post by yankoch »

Hello everybody,

I'd like to use CC to make a ground analysis with colors depending on height. Well, color variation is easy to get with the "height ramp" function, but unfortunately there is no scale displayed.
Does anyone know how to display this basic scale?

I also tried to make a height grid generation in order to get my ground in 2D so I could compare it with the original one, but I only get 10-20 points in the projection view.
Last solution for me was to open the entire xyz file in Excel and to change all Z values to the lowest one of the pointcloud, then to save the new pointcloud with another name. By doing that, I could get a 2D pointcloud of the original one and compare the 2 clouds.
But this method is quite complicated, especially if you have big files (Excel isn't able to open them).

So if anyone could help me to find an easy way to get a scale displayed to view the height variations, it would really help me.

Bye
daniel
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Location: Grenoble, France
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Re: Scale display in height ramp

Post by daniel »

Hello,

Color scale is only available for scalar fields (one floating point value associated to each point). The "Color ramp" tool is just a way to assign colors (R,G,B) to a cloud.

Therefore, to do what you want to do:
- you can indeed use the "height grid generation" tool, but be sure to enter a valid grid step (it should be much smaller than your cloud dimensions! If the default value gave you 10 or 20 points, try with '0.01' or even less - the grid step is expressed in the actual cloud units). Warning: this tool actually project the points along the 'Z' dimension.
- otherwise, you can simply set the 'Z' column in your file as a 'scalar field' instead of 'Z coordinate' when the ASCII file wizard appears (when you load the file). You'll get a 2D cloud with the height as scalar field.
- or better, duplicate the last column in your file with a tool like Notepad++ and you'll be able to open the cloud in 3D and assign the 4th column as as scalar field.

Goold luck,
Daniel, CloudCompare admin
daniel
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Joined: Wed Oct 13, 2010 7:34 am
Location: Grenoble, France
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Re: Scale display in height ramp

Post by daniel »

I forgot something:

Once you have a scalar field, check the 'display scale' checkbox at the bottom of the cloud 'Porperties', in the 'SF Scale' section (left side of the screen). See attached example.

Daniel
Attachments
Scalar field scale bar example
Scalar field scale bar example
cc_sf_scale.jpg (268.89 KiB) Viewed 16680 times
Daniel, CloudCompare admin
yankoch
Posts: 2
Joined: Wed Jul 13, 2011 10:06 pm

Re: Scale display in height ramp

Post by yankoch »

Ok thanks, it works well.

Yan
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