Using ArcGIS 10.4.1 I am trying to build a map of the best state camp grounds to go camping in and also to use a telescope. I have the camp site shapefile from DNR and used lightpollutionmap.info to build a RGB.tif of light pollution for Michigan Lower Peninsula. I then converted the RGB.tif to colormap because I couldn't figure out what to do with the three bands.

I then converted the colormap to a polygon shapefile and I now have a range from 0(least)-7(Most) for the amount of light pollution for 38k ID's... and from here I am lost.

I want to find what camp grounds have the least total value of light pollution around it, say 50km. So I created a buffer around each camp site and now want it to register the total value of the converted polygon shapefile behind it(presumably the ones with the lowest total value are in the darkest areas for better telescope usage). I tried dabbling in merge and intersect but I can't seem to find what I am looking for.

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    Intersect the buffers of the campsite points with light pollution class polygons followed by summary statistics to find the average, min and max light pollution class within each buffer... be sure to use the case field of the polygon ID so you can join back to the polygons. You could do this with your classified raster (spatial analyst required) with zonal statistics as table if your intersect is taking too long. – Michael Stimson Apr 18 '17 at 22:55

If you've got access to a Spatial Analyst license, I'd suggest you back up a step and use the raster (.tif) colormap instead of the 8-class shape file you mention creating. Use the Zonal Statistics to Table tool to calculate whatever stats you want (min, max, mean, median, sd, etc...) for each campsite buffer. I think the only catch is that this may not work if you have buffers that overlap each other.

  1. Ensure that your buffers have a unique id
  2. Run the intersect tool on the buffers and light pollution polygons.
  3. You now have the light pollution values that fall within your buffers.
  4. If you want to average the light pollution for each buffer, dissolve the intersect result on the buffer id field. In the 'Statistics Field(s)' select the light pollution attribute. For the 'Statistic Type', select 'Mean'. There are other cool options like 'Range' and 'Sum'. Also, make sure to untick 'Create multipart features'.

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