Hi there,
I would like to show in a graph a symmetric color driving from 0 green to either + and – to red. The peak at the bottom should be in colour yellow again.
All areas around 0 in green. Anyone an Idea? Cheers
MATLAB: Symmetric color map using surf
colour codeMATLAB and Simulink Student Suitesurf
Related Solutions
This works:
T = [0,1,0; 1,1,0; 1,0,0]; % Green - Yellow - Red
T = interp1([1:3]', T, linspace(1, 3, 5)');m = 161;map = zeros(m , 3);x = [0 50 120 160 255];map = interp1(x/255,T,linspace(0,1,255));I = linspace(0,1,255);imagesc(I(ones(1,10),:)')colormap(map)The color interpolation carried out by MATLAB is not symetric by values but also by order. This induces the defect.
To trick MATLAB you have te reorganize the data
Z=[0 0.1 0.3 0.1 0; 0 0.2198 0.4432532 0.2198 0; 0 0.4242 0.7898989 0.4242 0; 0 0.2198 0.4432532 0.2198 0; 0 0.1 0.3 0.1 0];[X,Y] = meshgrid(0:1.5:6,0:1.5:6);x = linspace(-1,1,size(Z,2));y = linspace(-1,1,size(Z,1));close allhold onfor k=1:4 if k<=2 ix = find(x>=0); else ix = flip(find(x<=0)); end if mod(k,2)==0 iy = find(y>=0); else iy = flip(find(y<=0)); end surf(X(iy,ix), Y(iy,ix), Z(iy,ix), 'LineStyle', '-', 'FaceColor', 'interp')enddaspect([1,1,0.2])colormap(jet)colorbar
Defect coloring when using single SURF command
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