[GRASS-user] v.centroids (duplicate centroids and areas without centroid)

tim.ritter at arcor.de tim.ritter at arcor.de
Wed Jun 4 10:29:50 EDT 2008

Hi everybody,

I have a problem using v.centroids:
I created a map of landscape fragmentation by roads and other linear features, then converted the lines to boundaries with the command

      > v.type input=grenzen2 output=grenzen3 type=line,boundary --overwrite <

In the next step I cleand up the map with 

     > v.clean input=grenzen3 output=grenzen4 type=boundary tool=rmdangle,rmbridge,rmdupl,rmdac,bpol,rmline thres=-1 --overwrite<

because there were still inncorrect boundaries I used the same command once more:

     > v.clean input=grenzen4 output=grenzen5 type=boundary tool=rmdangle,rmbridge,rmdupl,rmdac,bpol,rmline thres=-1 --overwrite<

So far so good, but then I treid to attach centroids to my new areas by using

     > v.centroids input=grenzen5 output=grenzen6 option=add --overwrite<

the result was 
     >Number of duplicate centroids    :   4266
     >Number of areas without centroid :   4266

I tried to manually add some centroids to the areas without centroid by v.digit, and that worked fine, but I don't want to do it for 4266 areas, and I also have no idea why there are areas with duplicate centroids.

Any idea what to do?

Thanks in advance, 



Tim Ritter, B.Sc.
Springstraße 46a
37077 Göttingen

Tel.:  0551 / 389 3 114
Fax.: 0551 / 389 3 115
Mobil: 0173 / 284 3 664

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