How can I make a "color map" plot in matlab?

Question

I have some data (a function of two parameters) stored in a matlab format, and I'd like to use matlab to plot it. Once I read the data in, I use mesh() to make a plot. My mesh() plot gives me the the value of the function as a color and a surface height, like this:

What matlab plotting function should I use to make a 2D mesh plot where the dependent variable is represented as only a color? I'm looking for something like pm3d map in gnuplot.

Answer 1

By default mesh will color surface values based on the (default) jet colormap (i.e. hot is higher). You can additionally use surf for filled surface patches and set the 'EdgeColor' property to 'None' (so the patch edges are non-visible).

[X,Y] = meshgrid(-8:.5:8); R = sqrt(X.^2 + Y.^2) + eps; Z = sin(R)./R;  % surface in 3D figure; surf(Z,'EdgeColor','None'); 

2D map: You can get a 2D map by switching the view property of the figure

% 2D map using view figure; surf(Z,'EdgeColor','None'); view(2);     

... or treating the values in Z as a matrix, viewing it as a scaled image using imagesc and selecting an appropriate colormap.

% using imagesc to view just Z figure; imagesc(Z);  colormap jet;  

The color pallet of the map is controlled by colormap(map), where map can be custom or any of the built-in colormaps provided by MATLAB:

Update/Refining the map: Several design options on the map (resolution, smoothing, axis etc.) can be controlled by the regular MATLAB options. As @Floris points out, here is a smoothed, equal-axis, no-axis labels maps, adapted to this example:

figure; surf(X, Y, Z,'EdgeColor', 'None', 'facecolor', 'interp'); view(2); axis equal;  axis off;