Question

Extracting overlapped polygons


Badge +6

Hello,

I have 2 polygons overlapped. I'd like to split polygons into two A, B. Have tried with DonutBuilder and DonutHoleExtractor transformers, but it still looks overlapped

 

Please advise how to split the polygons.

 

Original Polygon

Output Polygon after using DonutBuilder / DonutHoleExtractor:

In Fig-1, the polygons are overlapped.

In Fig-2, here the polygon is highlighted when we click on it.

Tagging @takashi, @david_r, @DaveAtSafe


7 replies

Badge +2

The DonutBuilder has a parameter Drop Holes: Yes|No. Try using Drop Holes = Yes. However, it does look like your areas touch, in which cae you don't really have a donut. You might try AreaOnAreaOverlayer instead.

Badge +6
@MarkAtSafe

Have tried with DonutBuilder with Drop Holes and hidden polygon is being dropped. However I need both polygons with no overlaps.

Userlevel 2
Badge +17

If the DonutBuilder can create a donut from the polygons, you can just set No to the Drop Holes parameter to keep both the donut and the hole. You should not use the DonutHoleExtractor.

Badge +6

If the DonutBuilder can create a donut from the polygons, you can just set No to the Drop Holes parameter to keep both the donut and the hole. You should not use the DonutHoleExtractor.

@takashi - DropHoles parameter was set to NO, but the polygons still doesn't split.

 

Badge +2

If the DonutBuilder can create a donut from the polygons, you can just set No to the Drop Holes parameter to keep both the donut and the hole. You should not use the DonutHoleExtractor.

@fmeuser_gc I think you'll have to attach a sample of the data.

 

As I mentioned before, it does look like your area might not be a valid donut - it looks like the hole touches the shell. If you can attach a small sample of the data, members of the community can take a look and try and understand why your donuts aren't forming as you expect.

 

Userlevel 1
Badge +21
@fmeuser_gc I think you'll have to attach a sample of the data.

 

As I mentioned before, it does look like your area might not be a valid donut - it looks like the hole touches the shell. If you can attach a small sample of the data, members of the community can take a look and try and understand why your donuts aren't forming as you expect.

 

The donutbuilder will still create a donut if the hole only touches at a single point of the shell (albeit one that will fail validation for self interesections). Starts to do funky stuff if there is an overlap (in 2017 anyway, might have changed in 2018)

 

 

Badge +6
@fmeuser_gc I think you'll have to attach a sample of the data.

 

As I mentioned before, it does look like your area might not be a valid donut - it looks like the hole touches the shell. If you can attach a small sample of the data, members of the community can take a look and try and understand why your donuts aren't forming as you expect.

 

@MarkAtSafe - Is there a way to attach file > 1 MB? I couldn't attach .SHP file due to larger size.

 

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