Global Population Count Grid Time Series Estimates

The Global Population Count Grid Time Series Estimates provide a back-cast time series of population grids based on the year 2000 population grid from SEDAC's Global Rural-Urban Mapping Project, Version 1 (GRUMPv1) data set. The grids were created by using rates of population change between decades from the coarser resolution History Database of the Global Environment (HYDE) database to back-cast the GRUMPv1 population count grids. Mismatches between the spatial extent of the HYDE calculated rates and GRUMPv1 population data were resolved via infilling rate cells based on a focal mean of values. Finally, the grids were adjusted so that the population totals for each country equaled the UN World Population Prospects (2008 Revision) estimates for that country for the respective year (1970, 1980, 1990, and 2000). These data do not represent census observations for the years prior to 2000, and therefore can at best be thought of as estimations of the populations in given locations. The population grids are consistent internally within the time series, but are not recommended for use in creating longer time series with any other population grids, including GRUMPv1, Gridded Population of the World, Version 4 (GPWv4), or non-SEDAC developed population grids. These population grids served as an input to SEDAC's Global Estimated Net Migration Grids by Decade: 1970-2000 data set.
To provide back-cast population count estimates at 30 arc-second (~1 km) resolution.

全球人口计数格网时间序列估算数据集以社会经济数据与应用中心（SEDAC）的全球城乡制图项目第一版（Global Rural-Urban Mapping Project, Version 1, GRUMPv1）数据集的2000年人口格网为基础，构建了回溯式人口格网时间序列。该数据集的格网通过采用低分辨率全球环境历史数据库（History Database of the Global Environment, HYDE）中的十年间人口变化率，对GRUMPv1人口计数格网进行回溯推算而生成。针对HYDE计算所得变化率的空间范围与GRUMPv1人口数据之间的匹配偏差，本数据集通过基于邻域均值填充变化率格网的方式予以解决。最终，为使每个国家的人口总数与联合国世界人口展望（2008年修订版）对应年份（1970、1980、1990及2000年）的该国人口估算值一致，本数据集对所有格网进行了调整。本数据集并非2000年之前年份的人口普查观测数据，因此充其量仅可视为特定区域人口的估算值。本数据集的人口格网在时间序列内部具备一致性，但不建议与其他任何人口格网（包括GRUMPv1、世界人口格网第四版（Gridded Population of the World, Version 4, GPWv4）以及非SEDAC开发的人口格网）结合构建更长的时间序列。该人口格网曾作为SEDAC的《全球十年估算净迁移格网：1970-2000》数据集的输入数据。本数据集旨在提供30角秒（约1公里）分辨率的回溯式人口计数估算值。