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

[Micha Silver]

Roger André wrote:

> Hi GRASS list,
>
> I've imported a shapefile of country polygons and am trying to use
> v.clean properly to clean the topology.  Here is what I have done so
> far:
>
>   456  v.in.ogr dsn=unep_coastlines.shp -o type=boundary out=unep_countries
>   461  v.clean unep_countries out=unep_clean type=boundary
> tool=rmdangle,rmsa,break,rmdupl,rmbridge,bpol thresh=-1,0,0,0,0,0
>   
I think your list of tools and thresholds is odd:
tool            thresh         result
------------------------------------
rmdangle   -1         ignored
rmsa         0            does nothing

What you need is rmarea with a thresh >0  (as Martin pointed out) in 
addition to the break tool.
-- 
Micha
>   467  v.centroids unep_clean out=unep_clean_2
>   475  v.clean unep_clean_2 out=unep_clean_2_rmdac tool=rmdac thresh=0
>
> After doing this, I see that I still have some strange looking borders
> in Asia.  You can see what they look like here -
> http://lagerratrobe.blogspot.com/2009/10/using-grass-to-fix-topology.html.
>  I'm not 100% sure what the "x" means, but I think it indicates that
> the country border is not a solid line.
>
> How can I remove those extra bits, and create proper areas for each country?
>
> Thanks,
>
> Roger
> --
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