Abstract:
Gridded Population of the World, Version 3 (GPWv3) consists of estimates of human population for the years 1990, 1995, and 2000 by 2.5 arc-minute grid cells and associated datasets dated circa 2000. A proportional allocation gridding algorithm, utilizing more than 300,000 national and sub-national administrative units, is used to assign population values to grid cells. The population density grids
... are derived by dividing the population count grids by the land area grid and represent persons per square kilometer. The grids are available in various GIS-compatible data formats and geographic extents (global, continent [Antarctica not included], and country levels). GPWv3 is produced by the Columbia University Center for International Earth Science Information Network (CIESIN) in collaboration with Centro Internacional de Agricultura Tropical (CIAT).
The data in ARC/INFO Grid, American Standard Code for Information Interchange (ASCII), Band Interleaved by Line (BIL), Microsoft Excel (XLS) and maps in Portable Document Format (PDF) and Portable Network Graphics (PNG) formats are available from the NASA Socioeconomic Data and Applications Center (SEDAC). 
