2012/1/25 Sören Gebbert <[email protected]>: > Hi Martin, > many thanks for your example. It works fine with two layer. > > But is there a way to add categories to a number of layers larger than > two using the same vector map?
This will add new categories to a new layer, irrespective of how many layers are already defined: v.category option=add Note that a GRASS layer is defined by the existence of at least one vector feature with at least one category value in that layer. That layer may or may not be attached to an attribute table. For examples, see v.in.ogr when importing several layers at once, the LiDAR filtering tools, or the vector output of r.stream.extract. > Why is a full vector copy needed in case of category transfer from one > to another layer? Because category transfer takes place in the vector feature, i.e. modifies the coor file of the vector. v.category option=transfer does not add an attribute table (AFAIK). > > i just started to investigate the > new shiny world of multiple layer usage. I hope you enjoy it! Markus M > > Best regards > Soeren > > 2012/1/25 Martin Landa <[email protected]>: >> Hi, >> >> db.copy from_table=soil to_table=soil_2 >> >> -> makes copy of `soil` table >> >> v.db.addtable map=soil table=soil_2 layer=2 >> >> -> it would overwrite `soil_2` table, but do nothing in this case, no >> feature have category defined in layer 2. >> >> Proposal: >> >> v.random --o -z seed=1 output=soil n=20 zmin=0 zmax=100 column=clay >> v.category input=soil out=soil2 option=transfer layer=1,2 --o >> db.copy from_table=soil to_table=soil_2 >> v.db.connect map=soil2 table=soil_2 layer=2 >> >> v.db.addcolumn map=soil2 layer=1 columns='sand_frac DOUBLE PRECISION' >> v.db.addcolumn map=soil2 layer=2 columns='sand_frac DOUBLE PRECISION' >> ... >> >> Martin >> >> -- >> Martin Landa <landa.martin gmail.com> * http://geo.fsv.cvut.cz/~landa > _______________________________________________ > grass-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-dev _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
