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I'm looking for a way to join polygons to a density function for some other feature of interest.

Current workflow

  • make density raster from feature set of interest, using point/line/kernel density
  • sum raster inside output geometry (for polygons) or just sample it (for points)

This seems inefficient as I have to calculate a density raster for many points I won't even use. Is there a tool that does the same thing but without the raster? This would be like a kernel-density-aware spatial join, or a kernel density function that outputs to a preexisting geometry rather than to a raster.

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Because most kernel density rasters are computed using a fast Fourier Transform, and because this is tremendously faster than a direct calculation (even though it requires computing an entire rectangular grid of values), it's likely your imagined approach would be much less efficient in most applications. For a recent discussion of these issues, please see gis.stackexchange.com/questions/41058/…. – whuber♦ Nov 23 '12 at 21:22

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