Question

Split polygons to remove donuts

  • 25 July 2013
  • 4 replies
  • 50 views
R
Hi,

 

 

I have a dataset containing polygons with donuts. I need to remove these donuts as they are not allowed for further use of the dataset.

 

I manage to remove all these by identifying these polygons with the donutholeextractor. Then these identified polygons are plit by an itterative proces of overlaying them with a rectangular raster with decreasing cell size. As there are big polygons with small holes this gives me a result were these polygons are cut into many many parts instead of just 3-4 parts.

 

Is there a simpler/better way to split the donut polygons that is resulting in just a few new polygons without holes? It does not need to be the optimal solution. It is ok if a polygon is split in a few parts more than necessary. I just dont want to split it into 100+ parts to remove on donut as it is now.

 

 

Thx,

 

Rob

4 replies

redgeographics
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I'm a bit confused by your question. Does the OuterShell port of the DonutHoleExtractor not give you what you want, i.e. the outer shell of the donut, with the hole(s) filled in.

 

 

Alternatively... the DonutBridgeBuilder will turn a donut polygon into a simple (albeit self-touching) one by connecting the inner and outer shells with a double line.
R
Thx Hans.

 

 

What I tried to say was that I want to keep the total geometry and not only the outher shell. Only, the original geometry (including one ore more holes) has to split up in new geometries without holes.

 

 

Pretend that X1 and X2 are togehter the original geometry. In this case I want to create somehing similar to whats presented below: 2 new features that form the original geometry but don't have donuts themselves.

 

 

 

It seems that the DonutBridgeBuilder does the trick. I only need to test if this solution can be handled in the other software as the solution is quite special.

 

 

Thx,

 

Rob
J
Has anybody achieved this yet? The DonutBridgeBuilder seems to create the right connections from the holfes to the outer boundary but I cannot permanently split the outershells.
A

I had the same problem with holes and DonutBridgeBuilder solved it (in tab files)

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