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Hello Forum,

 

Is it possible to artificially create a polygon based on the lower edge of an existing polygon?

 

Imagine I have an existing polygon, I’d then want to create a new polygon that snaps to the lower edge of the existing polygon. The depth of that polygon doesn’t matter, for example it could just be roughly 50 metres away from the shared boundary. What really matters is that is snaps to the lower edge of the existing polygon.

 

An alternative approach could be that the artificially created polygon is a doughnut polygon which wraps around the existing polygon to say, a depth of 50 metres. I could then split it manually where required…

 

 

I hope this makes sense. Any ideas?

 

Thanks,

Stuart

When you say “lower edge” are you meaning all edges that are in the lower half of the polygon?
Or all edges that face south?
Not sure if this is more just a geometry problem or if you are working with projected data of say building footprints.

Thanks for that, ​@liamfez . Yes, the lower half of the polygon. I wouldn't want just south of it as it's complex polygon. Although it is mostly linear (west to east), is does bend around in places. So, in places I’d want what is south of it, but in other places it would be what west of it, and so on. And in some tiny spots, what’s north of it (see bottom right corner). This is the poly…

 

So, if I ended up with something like the below, that would be a suitable result…

 

The other idea is to create a doughnut polygon around it. I could ten split as required.

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