color-coding a 2D plot

Hello everybody,

I am wondering how we can plot a 2D figure,x vs. y, which the amplitude of a given mathematical function, let say f(x,y) where e.g. f=sqrt(x.^2+y.^2), is encoded with colors in 2D plot as if max(f) is shown with e.g. blue color and min(f) with red color.

thank you so much, --V

Answer 1

[Kevin Holst]

unfortunately shading interp doesn't seem to work on contourf so here's an inelegant solution to your problem.

[x,y] = meshgrid(-10:0.1:10,-10:0.1:10);  % just to get some x and y values
z = sqrt(x.^2 + y.^2);
surf(x,y,z)
shading interp
set(gca,'cameraposition',[0 0 180])  % this essentially turns a 3d surface plot into a 2d plot
colormap(flipud(jet))

[Vahid]

nice solution! thanks again :-D

Answer 2

[Kevin Holst]

how about:

[x,y] = meshgrid(-10:0.1:10,-10:0.1:10);  % just to get some x and y values
z = sqrt(x.^2 + y.^2);
contourf(x,y,z)
colormap(flipud(jet))

Is that what you're envisioning?

Answer 3

[Vahid]

Thanks Kevin! What I am looking for is very close to what your commands plot. I'd like to have a continuous color changing rather than using different colors, I mean contentiously changing from [0 0 1] to [1 0 0] which each three-element row vector is the RGB triple.