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.

Accepted Answer

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;
```

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

Solution

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