[GRASS-user] Re: v.delaunay and v.category problem
rchirgwin at ozemail.com.au
Wed Mar 30 17:14:50 EDT 2011
On 30/03/11 9:21 PM, grass-user-request at lists.osgeo.org wrote:
> Hi all,
> I'm trying to use v.delaunay to get the lines connecting centroids in
> thiessen polygons because I need to compute some statistics on the length of
> those segments.
> I'm facing a problem that maybe somebody could help me to solve.
> Basically I run v.delaunay with the -l option to get lines instead of the
> polygons, I get the resulting vector, but there is no attribute tables
> associated to it.
> My idea was to run v.db.addtable to create a new empty attribute table, then
> v.category to assign cat numbers and the v.to.db to compute and add to the
> attribute table the parameter I need (ie the length).
> The problem is that when I run v.category nothing happens, and the attribute
> table remains empty.
> Am I missing somethng?
> Any help appreciated.
> Ing. Andrea Pogliaghi
> Milano - Italy
1. Try skipping the v.category step. Try v.to.db option=cat column=cat
2. What do you get from v.info on the v.delaunay output?
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