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Remove duplicate features

  • 12 March 2024
  • 4 replies
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pabloolivaresm
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Hi, I have a geopackage with 5 million polygons, some of which are duplicated, but with geometry that isn't exactly the same. In the image below the dark red’s polygones means there duplicates.

I trying with transfomer matcher  with this set

 

It works but not all polygones duplicates are deleted. I got something like this

 

I know that at some point some polygons won't be able to be deleted because the geometry is too different.Maybe in can set the tolerance in 4 or more, but i think

Any idea if it can be done?

Thanks

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Best answer by liamfez 25 March 2024, 15:26

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redgeographics
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Userlevel 5
Badge +25

Yeah, try changing the vector tolerance and see if you can find the sweet spot where it matches all the duplicates but nothing more.

pabloolivaresm
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Badge +3

Yeah, try changing the vector tolerance and see if you can find the sweet spot where it matches all the duplicates but nothing more.

@redgeographics Hi I’m now trying in a different way. I get the centroids of polygons and then with Pointonareaoverlayer I get those polygons who overlap more than ‘x’ centroids to delete them. My problem is some of then are overlapped just in the bords like this one:

 

I get also polygons that are overlapped in the center like this one

 

I’d need to delete just the polygons of the second exemple. Do you know if it’s possible to calculate the overlapped area of the polygones to delete just all of them that overlap more than ‘%X’ by others polygones

liamfez
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Userlevel 4
Badge +13

“Do you know if it’s possible to calculate the overlapped area of the polygones to delete just all of them that overlap more than ‘%X’ by others polygones” @pabloolivaresm You could utilize the Clipper and the AreaCalculator.for this. If you calculate the initial area of the polygons, run them through the clipper and another AreaCalculator. Then using a StatisticsCalculator or Aggregator to sum the clipped areas per polygon you will get a total overlapped area. You can then use those numbers to get a %overlap.

pabloolivaresm
Rank
Badge +3

“Do you know if it’s possible to calculate the overlapped area of the polygones to delete just all of them that overlap more than ‘%X’ by others polygones” @pabloolivaresm You could utilize the Clipper and the AreaCalculator.for this. If you calculate the initial area of the polygons, run them through the clipper and another AreaCalculator. Then using a StatisticsCalculator or Aggregator to sum the clipped areas per polygon you will get a total overlapped area. You can then use those numbers to get a %overlap.

it works, thanks!

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