We have just added on WWF-SIGHT a set of data layers showing estimates of human population density, based on counts consistent with national censuses and population registers with respect to relative spatial distribution, but adjusted to match the 2015 Revision of UN World Population Prospects country totals for the years 2015 and 2020. A proportional allocation gridding algorithm, utilising approximately 12.5 million national and sub-national administrative units, is used to assign population values to 30 arc-second (~1 km) grid cells. The population density grids are created by dividing the population count grids by the land area grids. The pixel values represent persons per square kilometer.
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Interactive map of the Population Density of the World in 2015(Click on top left of the map for more info).