[GRASSLIST:8703] Re: v.digit boundary, centroid, topology issues

[Radim Blazek]

The red are in v.digit is not closed, you have to get it also green.

Radim

On 10/20/05, Graham Watt-Gremm <sunyata at uvic.ca> wrote:
> Hello all,
> I'm having problems making digitized boundaries reveal themselves as
> areas (6.1.cvs binaries on OSX 10.4.2). After creating polygons
> (category set to no category), placing centroids (mode next not
> used), and manually cleaning nodes (splitting lines and removing
> vertices) and ensuring node colour is the proper green, I exit
> v.digit and get the following response (from a test vector with just
> two polygons - one a closed single boundary line representing an open
> avalanche path and the second an adjoining woodland:
>
> Building topology ...
> Registering lines:
> 6 primitives registered
> Building areas:
>
> 1 areas built
> 1 isles built
> Attaching islands:
> Attaching centroids:
> Topology was built.
> Number of nodes     :   5
> Number of primitives:   6
> Number of points    :   0
> Number of lines     :   0
> Number of boundaries:   4
> Number of centroids :   2
> Number of areas     :   1
> Number of isles     :   1
> Number of incorrect boundaries   :   3
> Number of centroids outside area :   1
> %
>
> I examine the result using d.vect and find that the avalanche area
> displays and "queryable" anywhere, while the woodland does not show
> the area. I have been over and over the help archives (something
> similar was examined October 2003, but I could not figure it out for
> my situation), manuals, and such, and believe I understand the vector
> topology model - what do I need to do to "close" the polygon and have
> the centroid values assigned to it?
>
> (images viewable here: http://frog.envi.uvic.ca:81/~graham/
> v.digit_woes.htm)
>
> Thanks,
> Graham
>
>