I've managed to read in the 2.5 min GPWv3 population grid (95ag). When I inspect the file, I see "lines" of blended values between the population subregions (which are a field of a single number, presumably indicating the population in that subregion). I presume these "blended" values on the borders between subregions are artifacts of how the files were created, and do not represent valid population numbers. Am I correct?

These values do represent valid population values. Where a grid cell is covered by more than one administrative unit (subregion), the population assigned is an area-weighted proportional allocation.

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