Tell me more ×
Mathematica Stack Exchange is a question and answer site for users of Mathematica. It's 100% free, no registration required.
up vote 1 down vote favorite

How can I define a ColorFunction for my ContourPlot using Piecewise? For example after making a ContourPlot for such this function:

p[x_,y_]:=1-Sin[x]^2*Sin[y]^2;

I want to define my ColorFunction in a way that for example for 0<p<0.1 the plot have a different color than 0.1<p<0.2. An example of what I need is in the following plot: enter image description here

Which the color column at the right shows that each color corresponds to what value of p.

share|improve this question
Doesn't it just work by default? ContourPlot[1 - Sin[x]^2*Sin[y]^2, {x, 0, Pi}, {y, 0, Pi}, PlotLegends -> Automatic, ColorFunction -> "DarkRainbow"] – Vitaliy Kaurov Mar 25 at 23:00
@VitaliyKaurov Kaurov The thing is that I need to have control on the colors. In the plot that I have put as an example, e.g. dark orange corresponds to 0.8<p<0.9. ColorFunction -> "DarkRainbow" doesn't give me this option. – ZKT Mar 25 at 23:03

1 Answer

up vote 3 down vote accepted 
myBlend[x_] := Blend[{Purple, Blue, Cyan, Green, Yellow, Orange, Red}, x]
ContourPlot[p[x, y], {x, 0, \[Pi]}, {y, 0, \[Pi]}, Contours -> 25, ColorFunction -> myBlend]

or

myPiecewise[x_] := Piecewise[{{Red, 0 <= x <= 0.25}, {Orange, 0.25 < x <= 0.75}, {Yellow, 0.75 < x <= 1}]
ContourPlot[p[x, y], {x, 0, \[Pi]}, {y, 0, \[Pi]}, ColorFunction -> myPiecewise, ColorFunctionScaling -> False]

Remember to put ColorFunctionScaling -> False if you need precise control over the position of the colours.

<< PlotLegends`
ShowLegend[
  ContourPlot[2 p[x, y], {x, 0, \[Pi]}, {y, 0, \[Pi]}, ColorFunction -> myPiecewise],
  {myPiecewise, 10, "0", "1", LegendPosition -> {1.1, 0}}]

guide/PlotLegendsPackage

Note: I work with version 8. In version 9 it appears to have been integrated: ref/BarLegend

share|improve this answer
Thanks a lot for your help. Do you know how can I build that color column at the right hand side of the plot in the question? I need to explain the colors using that. – ZKT Mar 25 at 23:12

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.