On Tue, Mar 23, 2010 at 3:00 PM, maven apache <apachemaven0 at gmail.com> wrote: > Hi: > I have a raster image which contains some polygons,and now I want to extract > the boundary of them and change the boundary to vector, how to do that? I think that r.to.vect (f=area) and then a v.type will do that job. Markus