[GRASS-user] areas with no centroid

[Dave Roberts]

Hi Helmut,

    Thanks for the suggestion, but the area with no centroid doesn't 
have a cat.  I think somehow I deleted the centroid instead of the area, 
and the cat went with it.

    It's not really causing any problems I'm aware of; it's just odd.

Thanks, Dave

On 11/27/16 13:24, Helmut Kudrnovsky wrote:
> Dave Roberts wrote
>> After editing a map with wxgui I ended up with 39 areas and 38
>> centroids.  How do I find and delete the area with no centroid?
>>
>> I have tried many combinations of v.info, v.category, v.to.db, and
>> visualizing with d.vect.  If I use v.clean tool=rmarea with slowly
>> increasing thresholds it gets rid of an area I want before it finds the
>> one I don't so I don't think it's a sliver.
>>
>> GRASS GIS 7.3.svn > v.info demo
>>   . . .
>> Number of points:       0           Number of centroids: 38
>> Number of lines:        0           Number of boundaries: 112
>> Number of areas:       39           Number of islands:    19
>>   . . .
>> GRASS GIS 7.3.svn > v.category demo op=report
>> Layer/table: 1/demo
>> type       count        min        max
>> point          0          0          0
>> line           0          0          0
>> boundary       0          0          0
>> centroid      38          1         75
>> area           0          0          0
>> face           0          0          0
>> kernel         0          0          0
>> all           38          1         75
>>
>> Thanks, Dave
>> --
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>
> d. vect has following option :
>
> cat: Display category numbers of features
>
> try to display the cat info for the polygones to check where the centroid is
> missing.
>
> have then a look at v.extract and extract only these polygones you need.
>
> HTH
>
>
>
> -----
> best regards
> Helmut
> --
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