[GRASS-user] importing and cleaning overlapping polygons that are supposed to overlap

[Moritz Lennert]

On 14/05/19 23:46, Veronica Andreo wrote:
> Hi all,
> 
> I was working today with a very simple vector map which corresponds to 
> clusters (circular polygons) that overlap and it is just fine that they 
> overlap. So, i received a shapefile with 3 of these clusters. Two of 
> them overlaped. When I import them into GRASS with v.import I get an 
> extra centroid and area where 2 of the polygons overlap.
> 
> Problem arises when I want to query a raster map with those polygons 
> since originally the attribute table contained only 3 polygons (which is 
> just fine). However, v.what.rast will only upload values for 2 of those 
> three polygons because it finds 2 centroids with the same category, AFAIU.
> 
> I tried with
> 
> v.clean input=clusters output=clusters_clean1 tool=break,rmdupl,rmsa,rmdac
> 
> and
> 
> v.clean input=clusters type=centroid output=clusters_clean2 tool=rmdupl


If your overlap polygons are smaller than the cluser polygons, you could 
use v.clean rmarea with a relevant threshold.

Moritz