# Help with a color map

In this document http://pastebin.com/XEyrDHyB the first 2 coloums are the position and the third the value of the fuction.

I need to create a 2d image where in each position the value of the function is represented by a color. The highest value would have a different colour from the lowest. It would be great if the areas where the values of the function are similar are marked.

• Dec 30, 2016 at 17:41

Here's a few ways to visualize the data:

I've imported your data as a 524 by 3 matrix:

Dimensions[data]

{524, 3}


The easiest way is with ListDensityPlot:

ListDensityPlot[data, ColorFunction -> Hue]


For the other methods, I rescale the function values to run from 0 to 1:

data[[All, 3]] = Rescale[data[[All, 3]]];


A different approach is to use Graphics:

Graphics[
{Hue[#3], {Hue[#3], Cuboid[{#1, #2} - 0.015, {#1, #2} + 0.015]}} & @@@ data,
Frame -> True
]


Another is with ListPlot:

ListPlot[
Style[{#1, #2}, Hue[#3]] & @@@ data,
PlotStyle -> PointSize[0.03],
AspectRatio -> Automatic,
Axes -> False,
Frame -> True
]


As for marking similar values, you can use ClusterClassify. Here I partition into 4 groups:

c = ClusterClassify[data, 4];

Do[color[j] = RandomColor[], {j, 1, 4}]

Graphics[{color[#3], Cuboid[{#1, #2} - 0.015, {#1, #2} + 0.015]} & @@@
Map[Append[Most[#], c[#]] &, data], Frame -> True]