[GRASS-user] Collapsing many layers into 1

Martin Landa landa.martin at gmail.com
Tue Jan 22 04:58:18 EST 2008


Hi,

2008/1/22, Neil Godfrey <neil at thegodfreys.net>:
> The census 2000 administrative boundaries are shapefiles, where every
> county is a separate file.  So v.in.ogr creates a layer for every
> county.  So for example, I get 83 layers for the 83 counties in
> Michigan, which correspond to 83 tables, each with just one category.
>
> What I want is one layer with 83 categories.  I've had no luck with
> v.overlay, v.extract, v.patch, etc. because all those tools preserve the
> layers in the output map.
>
> Is there any way to do this?

If the attribute tables have the same structure (number of columns,
data types and key column), you can patch maps using

v.patch -e in=`g.mlist vect pat='con*' out=con_patch
v.clean in=con_patch out=con_clean tool=snap,break,rmdupl thresh=[value]

?

Martin

-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *


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