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Original Post: i got a huge list of points. Every point consists of four values. The first three values are X, Y and Z. The last one i need to use as the color of the point.

In Matlab the "scatter" function does it for me. There it is very easy, i only need to pass the 4th dimension of my array as a parameter for the color. But plotting pointclouds with more than 100.000 points is not efficient in matlab. Because of that i want to use ILNumerics.

If I'm right it is not possible to do it like matlab does, because ILNumerics need a Array[3] or Array[4] for the Color-Attribute of ILPoints.

Is there an easy way to convert my 4th-value into a Color-Attribute/Array which is needed by ILPoints.Color?

Thanks for your help!

Wayn0r

New Post:

Datasetup: A huge list of points with four parameters (X, Y, Z and let us call it color). With a normal StreamReader i read all lines and convert them to a List. After that i pass them to a float[] Array

        float[] xArray = xFloat.ToArray<float>();
        float[] yArray = yFloat.ToArray<float>();
        float[] zArray = zFloat.ToArray<float>();
        float[] colorArray = colorFloat.ToArray<float>();

After that i creat a ILArray an pass the float[] to this ILArray

        ILArray<float> points = ILMath.zeros<float>(4, xFloat.Count);
        points["0;:"] = xArray;
        points["1;:"] = yArray;
        points["2;:"] = zArray;
        points["3;:"] = colorArray;

If I create an Array of 4 dimensions the ILPanel is blank everytime i run/debug the tool. So actually I use this code to convert the X,Y,Z- and the Color-Information to ILArrays

        ILArray<float> points = ILMath.zeros<float>(3, xFloat.Count);
        points["0;:"] = xArray;
        points["1;:"] = yArray;
        points["2;:"] = zArray;

        ILArray<float> color = ILMath.zeros<float>(1, xFloat.Count);
        color["0;:"] = fzArray;

All my values are at position color["1;0"] and not as i coded it as position color["0;:"] because at position 0 there is the value "(:,:) 1e+003 * " and all data are in position 1 and are devided by 1000.

Nex i get the Limits of the color-ILArray to pass them to the ILStaticColormapProvider

            color.GetLimits(out min, out max);

        var cmProv = new ILNumerics.Drawing.Plotting.ILStaticColormapProvider(Colormaps.ILNumerics, min, max, AxisScale.Linear);

Everything else is identical to your linked code. For the "Colors" parameter of ILPoints i use Colors = cmProv.Colormap.Map(color["0;:"]).T

Everything is plotted and colored with different colors, but the colorbar range should be from -2081 up to 222, but it is from 30 up to 60. So the granularity of the used colors is not enough to see the differences between the plotted points.

Wayn0r
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  • http://stackoverflow.com/questions/24545293/how-to-add-a-colorbar-for-custom-objects-in-ilnumerics gives an example of using a colormap for the mapping from values to colors. – Haymo Kutschbach Jul 13 '14 at 07:03
  • Thanks for your answer. The code seems to be the right way to solve my problem, but the system can't find "ILStaticColormapProvider". Because of your statement "This is not working with the Community Edition from nuget!" I've installed the free trial version. – – Wayn0r Jul 14 '14 at 15:01
  • See the documentation here: http://ilnumerics.net/apidoc/?topic=html/T_ILNumerics_Drawing_Plotting_ILStaticColormapProvider.htm – Haymo Kutschbach Jul 15 '14 at 12:25
  • Thanks again, i've used the wrong *.dll. Now it works. But there is still one question: I used two ILArrays. One for the X,Y,Z-Values of the points, and the second for the color-value. The minimum of the color-values is -2081 and maximum is 222. But the range of the colorbar goes from 30 to 80. I used ILArray.GetLimits to get the limits and i pass these values to the constructor of ILStaticColormapProvider. What have to be done, that the colorbar uses the real min and max values? – Wayn0r Jul 16 '14 at 12:56
  • It sounds like this question deserves a complete new thread on SO :) Please include your code, describe the intended and the observed result. Thanks – Haymo Kutschbach Jul 16 '14 at 17:00
  • Have you tried providing the correct range to the colorbar? you could try: `points["2;:"].GetLimits(out min, out max);` Otherwise: it is not very easy to understand your question... – Haymo Kutschbach Jul 18 '14 at 08:29

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