Question

combine surfaces when they are attached

  • 21 February 2019
  • 5 replies
  • 8 views
I
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Hi ,

As you see in the image below ,i need to merge these small polygons to the bigger polygon beside,is there a way to do that?

Thanks!

5 replies

david_r
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Userlevel 4

If the small parts and the larger polygon have a common ID, you can use the Dissolver transformer with the common ID as the "Group By" attribute.

I
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thanks @david_r for your answer , No ,they don't have a common ID ,no attributs ,just geometry

ebygomm
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Userlevel 1
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thanks @david_r for your answer , No ,they don't have a common ID ,no attributs ,just geometry

If you don't have a common ID to dissolve on you'll need to create some rules to determine which polygons should be dissolved together, e.g. you might decide that everything under a certain area should be dissolved to the adjacent polygon

I
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If you don't have a common ID to dissolve on you'll need to create some rules to determine which polygons should be dissolved together, e.g. you might decide that everything under a certain area should be dissolved to the adjacent polygon

thanks @ egomm but where can I find this option?

ebygomm
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Userlevel 1
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thanks @ egomm but where can I find this option?

It's not a single option. You would have to find all polygons less than 100sqm, find which polygons neighbour them, choose which to merge with, assign a common id and then dissolve. Depending on the complexity of your data it can get quite involved

A simple example

dissolve_small_polygons.fmwt

 

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