If a polygon has no other touching it, it should have 2 nodes and at
least 2 verticies.
When polygons touch other polygons, topology comes into play. So
when polygon B is adjacent to, and touching polygon A, that makes a
node because it is a shared line segment between polygon A and B. The
lines break with nodes when other features connect, to create
topologically correct, non-overlapping polygons.
Mark
On Apr 30, 2010, at 8:15 AM, Sophie Leguedois <sophie.legued...@ensaia.inpl-nancy.fr
> wrote:
Thank you very much for your useful answers. The commands v.to.point
and
v.out.ascii are doing the trick!
About vertices and nodes, I noticed that you can have several nodes
for the
boundary limit of a polygon. Why so? Is it beacuse the nature of the
neighbour polygon is different?
Regards,
So.L.
-----
Sophie Leguédois
Researcher - Inra (French National Institute for Agricultural
Research)
Laboratoire Sols et Environnement (UMR 1120 LSE)
Ensaia - 2 avenue de la Forêt de Haye
BP 172 - 54505 Vandoeuvre-lès-Nancy - France
Tel: +33 (0)3 83 59 57 62
http://www.lse.inpl-nancy.fr/
--
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