Find the volume under a 3D surface

I've plotted a 3D surface of point clouds using

surface(x,y,z)

The plot looks like below:

I want to measure the volume below the surface, i.e. the volume of space surrounded by the xy plane, the xz plane, and the surface. How can I do that? Any idea?

Thanks!

Answer 1

[John D'Errico]

Since this appears to be a gridded surface, then you can just use trapz, twice. Call it once on the x dimension, and once on the y dimension.