Question

How to find the majority from multiple areas

  • 4 March 2014
  • 2 replies
  • 4 views
V
i have 2 set of polygons, postal code boundaries and TRS

 

I want to find what postal codes each TRS overlaps and if it overlapps more then one postal boundary,

 

I want to select the postal code that takes up a largest area in the TRS.

 

 

I have use the SpatialRelator and got a list of all postal codes for each TRS, but not sure how to pick the one that have the majority.

 

 

I thought about using the centroid of the TRS but some sections overlapps many postal code boundaries and the centroid doesn't always fall in the majority.

 

 

Any suggestions will be appreciated.

 

 

Thanks

 

 

V

2 replies

takashi
Rank
Userlevel 2
Badge +17
Hi V,

 

 

I would use the AreaOnAreaOverlayer.

 

Send both postal boundaries and TRS polygons to the AreaOnAreaOvelayer. Output features will be areas which are divided by every boundaries. The divided areas retain every attribute of original features and also will have overlap count attribute named "_overlaps" by default.

 

Select overlapped areas (1 < _overlaps) using the Tester, and calculate their area using the AreaCalucaltor.

 

You can then select each largest area for every TRS. Sort them by area descending, and apply the Sampler or DuplicateRemover. Also see the neighbor question.

 

"Keeping the first entry of a list."

 

https://safecommunity.force.com/CommunityAnswers?id=906a0000000cx2EAAQ

 

 

In addition, I assume TRS polygons have unique ID attribute. If not, add temporary ID to them using the Counter beforehand.

 

 

# btw, what is "TRS" ?

 

 

Takashi
V
I will give that a try first thing tomorrow.

 

TRS stands for Township Range Section.

 

It is our map grid. Each section (TRS) is 1 sq mile.

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