On 26/11/13 03:39, Dave Roberts wrote:
Friends,I'm not exactly a newbie, but still yet quite naive in GRASS. This seems like a simple problem, but I suspect unforeseen problems with the simple solution. I have imported a surficial geology map from a shapefile. There are 1082 polygons. Each of the polygons with the same surficial geology (e.g Agn, Archean gneiss) has the same cat (i.e. there are 29 polygons with cat=3). I would like to add several columns to this table (e.g. geologic era and primary lithology (e.g. granite vs limestone)). I normally associate all vector maps with a table in PostgreSQL using cat as the primary key (i.e. v.db.connect -o key=cat), but that clearly won't work here. I could rename the column 'cat' in the DBF file, and add a new column with values 1-1082 as cat. If I save that as a new DBF file in a new shapefile directory, when I re-import with v.in.ogr will it necessarily get it right? I.e, will GRASS associate the vertices the first polygon in the shapefile with the first row in the DBF file? I only ask because PostgreSQl (like most DBMSs) does not guarantee the records to be in any specific order, and perhaps shapefiles don't either? Is there a simple way to renumber the polygons 1 through 1082 that maintains integrity and allows me to connect the vector coverage to PostgreSQL instead of DBF?
Doesn't v.in.ogr attribute new, unique cat values to every polygon ? Could you give us the exact command for importing the shapefile ? Moritz _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
