Is it possible to overlay pcolor plots using hold on?

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Ajmal Rasheeda Satheesh on 9 Feb 2022
Answered: Walter Roberson on 9 Feb 2022
I was trying to overlay pcolor plots using hold on but I get the following error "Error using colormap (line 61) First argument must be a scalar axes or figure handle".
Any idea on what might be going wrong? Thanks
f1 = figure(Visible="on");
Y=pcolor(T,H, A');
set(Y, 'EdgeColor', 'none');
set(gca,'ColorScale','log');
hold on
Z=pcolor(T,H, abs(B'));
set(Z, 'EdgeColor', 'none');
set(gca,'ColorScale','log');
cmp1 = colormap(jet);
cmp1 = [1 1 1;cmp1];
cmp2 = colormap("parula");
cmp2 = [1 1 1;cmp2];
colormap(Y,cmp1);
colormap(Z,cmp2);
hold off

Highphi on 9 Feb 2022
f1 = figure;% (Visible="on");
Y = pcolor(T, H, A');
set(Y, 'EdgeColor', 'none');
set(gca,'ColorScale','log');
hold on
cmp1 = colormap(jet);
cmp1 = [1 1 1;cmp1];
set(gca, 'Colormap', cmp1)
Z = pcolor(T, H, abs(B'));
set(Z, 'EdgeColor', 'none');
set(gca,'ColorScale','log');
cmp2 = colormap("parula");
cmp2 = [1 1 1;cmp2];
set(gca, 'Colormap', cmp2);
hold off
Walter Roberson on 9 Feb 2022
You are using the same axes both times there, but any one axes can only have one colormap.
See the File Exchange contribution FreezeColors()

Walter Roberson on 9 Feb 2022
colormap(Y,cmp1);
If you pass in more than one positional parameter to colormap, then the first parameter must be an axes.
It is not possible to colormap() individual pcolor() objects.
You can however use rescale() (or the earlier mat2gray()) to convert the input values to the 0 to 1 range, multiply by the number of colors in the color map, floor(), uint8(), and then ind2rgb() against the colormap, in order to get an RGB equivalent. Or use the FIle Exchange contribution Freeze Colors.

R2021b

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