[GRASS-user] v.delaunay and v.category problem

[Andrea Pogliaghi]

just to make it clearer.... if I do the above steps with v.delaunay, then I
create the table with v.db.addtable and then I run v.category, it works
fine.
If I do the same steps with v.delaunay with the -l flag (and I have to,
since I need the lines), then it doesn't.

cheers
Andrea


On Thu, Mar 31, 2011 at 4:37 PM, Andrea Pogliaghi <
andrea.pogliaghi at gmail.com> wrote:

> On Thu, Mar 31, 2011 at 2:54 PM, Maris Nartiss <maris.gis at gmail.com>wrote:
>
>> Hello,
>>
>> 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."
>
> cheers
> andrea
>
>
>> Maris.
>>
>>
>> 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>
>> wrote:
>> >
>> >> 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
>> output
>> > 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
>> would
>> > 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
>> compute
>> > the length of each line, as I need to know which is their min, max and
>> avg.
>> >
>> > 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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