Contourf plot in discrete range
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I have a matrix the values of which ranges from ~0.000001 to ~0.004. I want to separate the colors like this.. 1e-6 to 2e-6 (one color), 2e-6 to 5e-6 (next color), then 5e-6 to 1e-5, 1e-5 to 2e-5, 2e-5 to 5e-5, 5e-5 to 1e-4, 1e-4 to 2e-4, 2e-4 to 5e-4, 5e-4 to 1e-3, 1e-3 to 2e-3, 2e-3 to 3e-3, then 3e-3 to higher values. Here, 1e-6 = 0.000001. Somehow I managed to give different range of values to different colors, but the whole discrete set of ranges is not showed up in the caxis. It only showed discrete range in caxis for values higher than 0.0005, values below that, i.e. 0 to 0.0005 shown only by a single color. Similar to the attached picture is what I want..Could anyone please help..?? Thanks in advance
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Answers (2)
KSSV
on 7 Aug 2018
Edited: KSSV
on 7 Aug 2018
[Z,txt,raw] = xlsread('data.xlsx') ;
Z(Z==-9999) = NaN ;
pcolor(Z) ;
shading interp
colorbar
%%Fix Ranges
R = [5e-6 1e-5 ;1e-5 2e-5; 2e-5 5e-5; 5e-5 1e-4; 1e-4 2e-4;2e-4 5e-4; 5e-4 1e-3; 1e-3 2e-3; 2e-3 3e-3 ;3e-3 inf] ;
C = rand(size(R,1),3) ; % fix random colors, you can use your custom RGB colors here
A = Z ;
for i = 1:size(R,1)
idx = Z>=R(i,1) & Z< R(i,2) ;
A(idx) = R(i,2) ;
end
figure
shading interp
pcolor(A)
shading interp
colorbar
colormap(C)
5 Comments
Marco Sandoval
on 1 Mar 2019
Hi..
I have the same question. Any luck?
The solution given above is not 100% correct, because it is changing the real values to the upper limit of each range, and when you do a pcolor graph, it doesn't looks like the original.. instead it's seems very rude, as low resolution.
Is there a way of manage the range of numbers of each color in a discrete palette? I mean, something like:
between -inf and 20, one color (considering all real numbers in between)
between 20 and 40, other color
... etc.
I have seen solutions but with surf and scatter functions (because they have an option for colors), but I'm asking for pcolor or contourf.
regards!
1 Comment
Walter Roberson
on 1 Mar 2019
Edited: Walter Roberson
on 1 Mar 2019
pcolor() is implemented as surf() followed by view(2) . However, pcolor() accepts very few options.
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