I tried to contact the i.vi author, Ray Terrill, at the email address in the manual and my email bounced. i.vi is producing 0-value maps, possibly because it is doing integer maps when it should be doing float math somewhere.
Michael
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University
voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu