[GRASS-user] HowTo fix country border topology problem?

Martin Landa landa.martin at gmail.com
Sat Oct 17 03:57:55 EDT 2009


Hi,

2009/10/17 Roger André <randre at gmail.com>:
> Tried the v.extract route - it didn't help.  The little segments came

sure, because there are no 'lines' - just 'boundaries' and 'centroids'
which constract 'areas'.

> along.  So I decided to look at the original data and pull one the
> polygons from it, to see if I could spot anything strange about it.  I
> did find something, maybe, maybe one of the experts here can explain
> it.
>
> Here is what v.clean reports:
>
> Number of nodes: 55
> Number of primitives: 59
> Number of points: 0
> Number of lines: 0
> Number of boundaries: 46
> Number of centroids: 13
> Number of areas: 13
> Number of isles: 9
>
> This country should have 9 areas, which matches the number of isles.
> I'm trying to figure out how to remove the extra areas (rmarea thresh
> value is tricky), but I wonder if there is a way to make the areas
> match the isles?

I was facing probably to the similar problem, it's described here [1].
Sorry it's in Czech, anyway from the commands you can probably
understand what was the problem. I hope it can help you a bit.

Martin

[1] http://gama.fsv.cvut.cz/wiki/index.php/GRASS_GIS_-_Konzistence_vektorov%C3%BDch_dat

-- 
Martin Landa <landa.martin gmail.com> * http://gama.fsv.cvut.cz/~landa


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