Question

Overlapping polygons and latest date filter.

  • 10 November 2017
  • 1 reply
  • 4 views

I have a dataset of state pesticide permit polygons. Each polygon is identified by a permit number and site id plus there are attributes for effective date and expiration date. In many cases the polygons overlap in one of three ways:

  • 1. Edge overlaps where imprecise drawing causes overlaps.
  • 2. Polygons are designed to represent the same area. Sometimes these are drawn slightly differently so they are not exact matches

  • 3. The same area is divided into different numbers of polygons at different times.

What I need to do is take overlap cases 2 & 3 and keep the overlapping polygon with the most recent effective date.


1 reply

Userlevel 4
Badge +25

The AreaOnAreaOverlayer can do the overlaying for you, if you set it to generate a list and then use a ListSorter to sort that list on the effective date you can use a ListIndexer to grab the attributes of the most recent element as the attributes of the resulting feature.

If you're concerned about the slightly different boundaries you could try using a Snapper before the overlaying to try and clean it up a little bit.

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