[GRASS-user] v.delaunay and v.category problem
andrea.pogliaghi at gmail.com
Thu Mar 31 10:37:24 EDT 2011
On Thu, Mar 31, 2011 at 2:54 PM, Maris Nartiss <maris.gis at gmail.com> wrote:
> You have to connect Your vector map to database at first. Go to
> Databases->Manage database->New table (v.db.addtable) and run
> v.category afterwards.
That is exactly what I did. In fact in my first message I wrote
"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."
> 2011/3/31, Andrea Pogliaghi <andrea.pogliaghi at gmail.com>:
> > Hi Maris,
> > On Thu, Mar 31, 2011 at 10:25 AM, Maris Nartiss <maris.gis at gmail.com>
> >> Hello,
> >> as attributes belong to triangle froming nodes, how should output look
> >> like? Every triangle should get all three atributes? And what about
> >> lines? Two attributes, as every triangulation line has two nodes at
> >> their end?
> >> It makes sense that no attribute is associated to v.delaunay lines
> > because the features (lines in my case as I'm using the -l switch) are
> > different from the nodes (even if having an output attribute table
> > containing, for instance, the attributes of the two nodes of each line
> > be useful), but that is not the point.
> > The issue I'm facing is that I want to create a new attribute table for
> > these delaunay_lines with a new unique cat value for every line and
> > the length of each line, as I need to know which is their min, max and
> > Cheers,
> > Andrea
> >> Maris.
> >> 2011/3/30, Andrea Pogliaghi <andrea.pogliaghi at gmail.com>:
> >> > Hi all,
> >> > ...
> >> > 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.
> >> > ...
> >> > Ing. Andrea Pogliaghi
> >> > Milano - Italy
> >> >
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