I have contributed a short (6 page) tutorial on the
use of v.autocorr (which justifies the existence of s.voronoi).
It briefly explains the Geary Ratio and the Moran Coefficient,
gives equations for them, shows how Thiessen or Voronoi polygons
are created from a GRASS site file, and shows how v.autocorr
can be used to test the hypothesis that spatial autocorrelation
exists.
The PostScript tutorial and shar files for these two commands
are currently in the incoming directory on moon.cecer.army.mil.
I would appreciate any feedback on either the commands or the
tutorial.
--Darrell