[GRASS-user] Re: [GRASSLIST:1175] add centroids automatically to area boundaries

[Moritz Lennert]

On Thu, August 10, 2006 15:33, Ulrich Leopold wrote:
>>> I have a patched vector map with lines. These lines should be converted
>>> into area boundaries in order to receive areas. Once boundaries are
>>> retrieved I still need  to attach centroids to them in order to overlay
>>> with *another* vector map which already consists of boundaries and
>>> areas
>>> including centroids. How can I achieve this?
>>>
>>> I tried to convert all lines into boundaries with
>>> v.type type=line,boundary
>>>
>>> It seems to work as there are only boundaries left. Next step would be
>>> to add automatically centroids to these boundaries. How can this be
>>> done?
>>
>> Hi,
>>
>> see v.category for this. I have added a micro FAQ for this:
>> http://grass.gdf-hannover.de/wiki/Convert_vector_types
>
> I tried that already but it did not work. It even changes the polygons
> back to
> single lines. But good that you opened a micro FAQ to add the solution
> later.
> Any other ideas?

Are you sure your lines are closed, thus defining real areas ? You can
check with v.digit.

Moritz