Building on more than 20 years of effort to improve mapping of human population, the fourth version of the Gridded Population of the World (GPWv4) data collection has been released. This new version provides scientists, applied users, and the general public with a more detailed and consistent view of the spatial distribution of population over two decades, designed to support interdisciplinary understanding and analysis of the interactions between human and environmental systems.
GPWv4 includes population estimates and projections at five-year intervals from 2000 to 2020 at a higher resolution than previous versions: 30 arc-seconds, or approximately 1 kilometer (0.6 miles) at the equator. GPWv4 reflects data from the 2010 round of national censuses, which occurred mainly between 2005 and 2014. The NASA Socioeconomic Data and Applications Center (SEDAC) operated by CIESIN collected and carefully matched population and boundary data for more than 13 million subnational administrative units, a 31-fold increase over version 3. Improved data were obtained for more than 100 countries including many small-island nations.
Grids of population counts and density, land area, water area, and data quality indicators are available for free download. Two different sets of population grids have been produced, one reflecting population totals reported by each country and another adjusted to national statistics developed by the United Nations (UN). Files may be downloaded for use in Geographic Information System (GIS) software or other analysis packages. The collection also includes a data set of the central point locations for subnational administrative units, for users needing tabular or vector (point) data.
In addition, SEDAC offers a range of map services and clients to visualize and access GPWv4 data, including the SEDAC Map Viewer, the Population Estimation Service, and the Hazards and Population (HazPop) mobile app for iOS devices. Several of these clients enable users to estimate the population residing within a user-defined circle or polygon, based on GPWv4 data for the year 2015.
GPWv4 is unique in characterizing population distribution based only on national census results, which enables it to be compared and combined with other types and sources of data. Other gridded population data products such as those available from the WorldPop project, the European Commission′s Joint Research Centre (JRC), and the Oak Ridge National Laboratory (ORNL) utilize additional data layers to model population distribution, which may preclude their use for some research and applications. CIESIN has been collaborating with the JRC, Facebook′s Connectivity Lab, WorldPop, and other groups to produce complementary gridded products consistent with GPWv4, such as the Global Human Settlements Population Grid (GHS-POP), the High Resolution Settlement Layer (HRSL), and the planned WorldPop global layer. Gridded population products are useful in diverse applications such as estimating population exposure and vulnerability to natural and technological hazards, determining accessibility to markets or services, and managing land, water, and ecosystem resources.
SEDAC is working to add additional gridded variables to the GPWv4 data collection, including data on age structure, gender, and urban vs. rural population, which should be available by mid-2017. GPWv4 data are made available openly at no cost under a Creative Commons Attribution 4.0 International License (CC-BY-4.0). Users are asked to register using a NASA Earthdata login when downloading data from the SEDAC site. SEDAC is one of the Distributed Active Archive Centers (DAACs) in NASA's Earth Observing System Data and Information System (EOSDIS), and has the mission to develop and operate applications that support the integration of socioeconomic and earth science data and to serve as an “Information Gateway″between the earth and social sciences.
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Gridded Population of the World v4 Data Collection