I have a shapefile that contains many overlapping polygons, each with an attribute for the year associated with the polygon (shown below). I would like to create an unstacked (no overlaps) polygon layer with polygons representing the most recent year.
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Eric
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Have you looked at the Select tool? – PolyGeo Jun 19 '20 at 06:39
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Hi @PolyGeo, I am aware of that tool/definition query and it doesn't do exactly what I need for this. The desired outcome of mine would be akin to the following: If each year's polygons (wildfires) is a single layer, I would like to "stack" them like a deck of cards, with the most recent year on top and the earliest year on the bottom. Then, I would like to sort of "squeeze" all of the visible bits into a single layer (single card) and the output would be most recent fire for any given coordinate. – Eric Jun 19 '20 at 06:55
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This can be done and is best automated in modelbuilder.
Using the Union tool, where they overlap you will get as many polygons that overlap and where they don't overlap you get the original polygon part. Then its a simple case of sorting the overlaps by date.
How do you identify the overlaps? Well I would extract out the centroids and use the XY of thoses as an ID field then fed that through a summary stats tool to identify the most recent date in that stack of overlaps.
Running the delete identical tool will reduce the stack of overlaps to a single polygon but as you have the centroid data you can join back the sorted summary data.
This approach will deal with partial overlaps as well as complete overlaps that would cause donut affects in your final output.
Hornbydd
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