On Wed, May 2, 2012 at 6:21 PM, Rich Shepard <[email protected]> wrote: > The basin map output from r.watershed is called 'dem.basin'. When I query > a basin I see the easting and northing of the point where I clicked, and a > numeric site_name variable. I've not checked all polygons, but I assume each > is uniquely numbered. > > First question: where in the mapset's directory structure is this > site_name variable stored? I've looked in the subdirectories with a > dem.basin file and do not see them.
It is in the cats/ subdirectory. See the second drawing in http://grass.osgeo.org/programming6/ for the structure. > Converting this raster map to a vector using r.to.vect with an output name > of 'basinv', creates a postgres table with three attribute columns: cat, > value, and label. The latter is blank for all rows. The value column, > however, has the same number repeated for different polygons. > > Second question: how are these value numbers created? They are created if the raster maps has category labels (see r.category). North Carolina example. GRASS 6.4.3svn (nc_spm_08):~ > r.category zipcodes 27511 CARY 27513 CARY 27518 CARY 27529 GARNER ... GRASS 6.4.3svn (nc_spm_08):~ > g.region rast=zipcodes -p projection: 99 (Lambert Conformal Conic) zone: 0 datum: nad83 ellipsoid: a=6378137 es=0.006694380022900787 north: 228500 south: 215000 west: 630000 east: 645000 nsres: 10 ewres: 10 rows: 1350 cols: 1500 cells: 2025000 GRASS 6.4.3svn (nc_spm_08):~ > r.to.vect in=zipcodes out=myzipcodes feature=area Extracting areas... ... r.to.vect complete. GRASS 6.4.3svn (nc_spm_08):~ > v.db.select myzipcodes cat|value|label 1|27513|CARY 2|27607|RALEIGH 3|27608|RALEIGH 4|27604|RALEIGH 5|27603|RALEIGH ... Works nicely. > Third question: why are there multiple values for different vector > polygons where there are distinct site_name numeric values in the raster > map? Maybe too late here, I don't get the last question. Markus _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
