Way to determine extent of vector flow field 2D and 3D

Hello, I'm currently looking for a solution for determining the extent of a vector flow field in both 2 and 3 dimensions. I'm unsure how to do this or where to begin. I simply want to graphically show the extent (at the surface) of the flow field instead of just showing vector arrows. Possibly as a contour? As well, in 3D I imagine it would be similar. I've looked at the 'griddata' function and I'm unsure how to use this since I don't have a defined function; I only have a matrix of my velocity components (u,v,w) and the locations (x,y,z).

If anyone could be of any help it would greatly appreciated!

Cheers,

Jack