Removing polygon overlap

[Jsweez]

Hi everyone,

I'm looking for some ideas.  I have 2 sets of neighborhoods from two different providers.  Each set includes a polygon representing the neighborhood (many are irregular and sizes vary widely).  What I'm trying to do is keep all neighborhoods from set 1 and only those from set 2 that do not overlap or overlap up to 10% of their total area.  For those neighborhoods to include from set 2, I'd like to trim the overlapping sections so that they meet but do not intersect with their nearby neighborhoods.

I've got the selection logic down but where things seem to fall apart is when I try to trim.  I use the Spatial Match tool to find all intersects.  I then cut the overlap from the set 2 polygon using the Spatial Process tool.  From there, I use the Summarize tool to combine all the trimmed set 2 polygons (for cases where a polygon intersected with more than one neighbor).

When all is done, I find that some of the polygons identified as overlapping are still overlapping even after the Spatial Process tool has completed.  Not all of them, just a few.  I'm not sure why.  If I cut the intersection area, how can it still be overlapping?  Any ideas?

Thanks,

Jason

[DanM]

@Jsweez  Sorry, I replied to this yesterday but it looks like it didn't post.

What you will want to do is actually do a poly split to see which of the polygons created for each record is the Sliver or the polygon you want and the filter out what you don't want. I attached the workflow with that added. You may have to play with the Filters to remove exactly what you want. You will see that the first Filter is actually taking out what was identified as a whole. So in your first record you will see that one of the polygons is marked as True indicating a hole which looks to be an island on a lake.

[Jsweez]

Thanks Dan.  Let me work with your example to see if I can get it.  I really appreciate all the help and guidance.

[Jsweez]

Sorry to be a pain, but I'm still a little confused.  The sliver in my case is the little area of overlap between the polygons.  It isn't necessarily the island off the coast, which is isolated from the rest.  How would I split the overlapping area into a separate polygon to be removed? 

[DanM · Accepted solution]

@Jsweez  I attached an addition to the workflow so you can see the intersecting small parts of the polygons.  If you select the first record in the Browse tool results and choose the Spatial Obj_Process field on the map and choose the Zoom to Selected you will barely be able to see the polygon. Unfortunately, I have tried to cut these from your data, but due to the size of that polygon alteryx will not perform the spatial process to cut. As mentioned, Alteryx is not a GIS software and may have some limitations when things get as small as feet. You can see in the image below that the polygon that touched both is less than 20 feet. You can see that against the stop line in the road.

[Jsweez]

Got it, thanks Dan. That makes sense.  The polygons are pretty small so it's unlikely that anyone will find that overlap.

Thanks,

Jason