[GRASS-dev] Struggling using two layered vector maps with v.what.rast

Sören Gebbert soerengebbert at googlemail.com
Wed Jan 25 05:09:37 EST 2012

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?
Why is a full vector copy needed in case of category transfer from one
to another layer?

Sorry for my noobish questions, but i just started to investigate the
new shiny world of multiple layer usage.

Best regards

2012/1/25 Martin Landa <landa.martin at gmail.com>:
> 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

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