MATLAB Answers

Change colors of pcolor meeting spesific conditions

3 views (last 30 days)
Hi there
I have a 810x810 elevation data matrix (le's say Z). I want to plot it using pcolor with
colormap(winter(10))
However, for every Z <= 0, I want to change the color into one ocean blue or just plain red. Does anyone know how to do this?
Thanks.
Abdul

Accepted Answer

Walter Roberson
Walter Roberson on 25 Jul 2020
cmap = winter(10));
cmap(1,:) = [.7 0 0]; %plain red
Ztemp = max(0, Z);
pcolor(X, Y, Ztemp);
colormap(cmap)
When you use pcolor(), the Z coordinates are all set to 0, not to the value of the data, so it does not matter that your Z is not the "correct" Z, you won't be able to tell with datatips (not unless you use a custom datatip function.)
There are alternatives to pcolor() that do not set the Z to all 0, and for those alternative functions, it can be a bit tricky to arrange that all negative values are one color without affecting the correct functioning of the Z coordinate in datatips.
  3 Comments

Sign in to comment.

More Answers (0)

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!