computing surface normal with x-, y- z- coordinates

hello there

i have the x-, y-, z- coordinates of 105 points of a surface and would like to compute the surface normal at each point. is there a way to do this? surfnorm and surf don't seem to work, because the vector z is a vector of z-coordinates and not a function of x and y.

[Roger Stafford]

To define a surface, your 105 points need to approximate a 2D space. That seems to contradict your assertion that your z is a vector. In other words, a point (x,y,z) on the surface needs to have neighboring surface points in two directions, not just one direction, in order to determine the normal direction there. Can you please elucidate?