Colormap, mask data

Hello!

I'm processing some data and I want to improve the Figure 1 attached.

If I understood correctly, I can convert the NaN values to zero, and then I have the same blue tone.

If this is correct, how can I do that?

Or perhaps can I change the colormap scheme?

Basically I want the blue with the same tone, and keep the orange and yellows.

That is my real data, everything around is noise.

Thanks in advance!

Answer 1

[Raphael Pesch]

Hey,

It seems as if you want the light blue and dark blue elements in the same colour. I am not sure if there is a function to do this automatically, but you could solve the problem by implementing two loops. If the values that you want to bring to zeros are NaN-values, than you can detect them with the isnan command (https://de.mathworks.com/help/matlab/ref/isnan.html).

If the values that you look for is light blue, than you should bring all of those values to zero. In the picture you uploaded it seems as if the light blue values are noise values with a maximum value of 0.15, so you could bring all values that are lower than this to zero.

I guess all your values lie in a matrix. Lets say this matrix is called testMatrix, than you can use this code:

[n,m] = size(testMatrix)
testMatrixWithoutNoise = zeros(n,m)

for i = 1:n
    for j = 1:m
        if isnan(testMatrix(i,j))
            testMatrixWithoutNoise(i,j) = 0;
        else if testMatrix(i,j) <= 0.15
            testMatrixWithoutNoise(i,j) = 0;
        else
            testMatrixWithoutNoise(i,j) = testMatrix(i,j)
        end
    end
    end

And now all the noise and NaN values should be gone and you can colormap the Matrix testMatrixWithoutNoise.

I hope this is helpfull. :-)

Have a nice day!