This is a database query issue. You need something along the line of [newfield] = max([oldfield1],[oldfield2],...)
I don't know the exact syntax in SQL, but maybe this can point you in the right direction. Michael On 11/20/07 4:58 PM, "Corey Moffet" <[EMAIL PROTECTED]> wrote: > Dear GRASS users, > > I have a vector layer with area features that have 1 or more categories > and associated attributes linked with the centroid. I would like to > extract a single category for each centroid on the basis of some > attribute. > > For example, there are several areas in my study area and each area has > a fire history. The area may have been burned in one or more years. In > one area, lets say it burned in 1950 and 1970 so the centroid for this > area has 2 categories linked with it and the attribute YearBurn is 1950 > and 1970 for the 2 categories, respectively. I want a new layer that > has only one category linked to the centroid and the value 1970 (e.g., > max(YearBurn) as LastBurn) for the attribute "LastBurn." > > The database table is in dbf format. How can this be accomplished > without having to edit it by hand? __________________________________________ Michael Barton, Professor of Anthropology Director of Graduate Studies School of Human Evolution & Social Change Center for Social Dynamics and Complexity Arizona State University phone: 480-965-6213 fax: 480-965-7671 www: http://www.public.asu.edu/~cmbarton _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
