How can this be done in GRASS? I've search for error/confusion matrixes in GRASS but didn't find anything. Thanks for any help, -- Gualter Barbas Baptista gualter at gaia.org.pt ICQ# 8106393 jabber.org: gandhiano GAIA - Grupo de Acção e Intervenção Ambiental gaia at gaia.org.pt Portugal