How do I make a surf plot in MATLAB with irregularly spaced data?

Question

I know I can create a 3D surface plot in MATLAB by doing:

x = linspace(1,10,100);
y = linspace(10,20,100);

[X Y] = meshgrid(x,y);

Z = X * Y;

surf(X,Y,Z);

But this requires that all the nodes for the height map generated line up. I have a set of data which has arbitrary points (x,y) and a height (z). Is there a simple way to plot a graph which will generate a surface between the points in a similar fashion to surf?

Answer 1

Appologies, after some hunting I managed to answer my own question:

You can use the trisurf function:

tri = delaunay(x,y);
trisurf(tri,x,y,z);

If you have dense data you will want to do shading interp (or another value, check doc shading) so you don't get a black blob due to the grid.

Answer 2

It looks like you've found your answer by using DELAUNAY and TRISURF to generate and plot a triangulated surface.

As an alternative, you could also fit a regularly-spaced grid to your nonuniformly-spaced points in order to generate a surface that can be plotted with the SURF command. I discuss how this can be done using the TriScatteredInterp class (or the deprecated function GRIDDATA) in my answer to this other question on SO.