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Overlapping buffers

I'm using ArcGIS 10.3 to classify landcover within a 30-meter buffer of houses. I categorized this with the Image Classification toolbar, then converted the raster to polygon for calculation purposes. However, some of the houses have overlapping buffers, and after a spatial join & dissolve, one of the overlapping houses/buffer rings will "acquire" any intersecting polygons. This results in overcalculation of the landcover type for one buffer ring and undercalculation for the other (the selected blue polygon in the attached image illustrates this - it attached to the rightmost buffer).

The question is, how do I preserve the integrity of the individual buffers when calculating area for individual landcovers? In other words, how would I go about including the intersected area in each of the buffer rings, while maintaining only the proper total area for each buffer ring (3.14*30^2).

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If I understand your goal correctly:

A spatial join will not give you the result you're looking for. Instead,

  1. Buffer the houses with no dissolving
  2. Intersect your buffers and your land cover (you may want to union, if your land cover data do not cover the entire area of interest within all buffers--but that still depends on how you'd like to summarize later on.)
  3. If you wish to summarize total area within all buffers and total area of each land cover type, you would dissolve the intersection's output feature class on the land cover type field.

In general, I would recommend using a spatial join only when you've already considered intersect, union, and identity and are certain that they won't give you the result you're looking for.

  • Fantastic, that did the trick Tom. It turns out that the Spatial Join was the confounding factor. In the Dissolve I just dissolved by the landcover and ID fields to aggregate the landcover areas by buffer ring. Thanks for the help! – devman27 Aug 8 '16 at 22:50

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