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I'm trying to get the percentage of each U.S. county overlaying groundwater (data from the census and USGS respectively). They're both polygons.
I have 1) correctly projected the data and the layer (NAD 83, meters) 2) clipped the counties using a polygon corresponding to groundwater coverage 3) use calculate geography to obtain the areas, so that I can then figure out proportions/percentages. I create a new field for that (double).
I've been toying around with this and other methods, and I cannot get credible area values. They're tiny; almost all 0.01 - 0.1. One of my many hunches was that it's in decimal degrees, but I've projected the data, and it's still showing up incorrectly. The most frustrating part is that the county/state files won't calculate correctly either on their own, which is bizarre (Florida = 15 m2).