How to calculate the volume under a 3d surface plot

Question

I have a 3d surface named,k for example:

a=8;

k(b,c)=a;

surf(k)

how to compute the volume and size under the surface plot?

Answer 1

The volume is the integral (assuming k>=0). Use integral2.

f=@(x,y)(interp2(k,x,y))
volume = integral2(f,xmin,xmax,ymin,ymax)