Designating color to value in contourf

I have a data range from 0 to ~66000 and I need to plot the color white only when z=0 in contourf. I have read through the colormap options related to contourf and none of them suit such a large data set or provide a specific enough answer. There must be an easy fix for this! Thanks in advance!

[Walter Roberson]

Could you confirm that white should be displayed only for z = 0 exactly , and not for z = 0.0001 or z = 1?

Are you supplying a contour level for 0 and a different contour level for the smallest non-zero value?

[Jason Redding]

Yes, white should be displayed for z=0 only. My data is only counts though (all integers), so there are no decimals.

Yes, the goal is to give 0 its own contour level and then everything else (the smallest non-zero value and above) be scaled according to the data (which can change) if possible.

Answer 1

[Walter Roberson]

Using hints from https://www.mathworks.com/matlabcentral/answers/363059-how-do-i-label-a-contour-plot-in-the-same-colors-as-the-contour-lines#answer_287606

[~, hContour] = contourf(YourData, [0, other_levels_go_here]);
idx = hContour.LevelList == 0;
hContour.FacePrims(idx).ColorData = uint8([255; 255; 255; 255]);

[Jason Redding]

That helped! Thanks!!

Answer 2

[Jorge Pascual]

Good afternoon,

I have a picture about a foot with differents values of pressure, I would like to create a Pedobarography with this values, but as I have a 2D matrix I am having some problems. I would like to fix the maximun value in red, the lowest in blue, and then the rest of the image that isn't foot in black.

Using the answer that @Walter Roberson said I have this error " Unrecognized property 'ColorData' for class 'matlab.graphics.GraphicsPlaceholder'" or maybe I don't undertand how I have to fill the variables that he said.

Thank you in advanced.

[Walter Roberson]

Is idx possibly coming out empty? Is hCounter possibly coming out empty?

[Jorge Pascual]

The matrix is about 719x272, where the values go between 0-60 and 0 is outside the foot.

So I fill de varibles in this way:

[~, hContour] = contourf(Pedobarography1, [0, 60]);

idx = hContour.LevelList == 0;

hContour.FacePrims(idx).ColorData = uint8([255; 255; 255; 255]);