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.

全球人口计数网格时间序列估计数据集，基于2000年SEDAC全球农村-城市映射项目第一版（GRUMPv1）的人口网格数据，提供了一种回溯式的时间序列人口网格。通过运用全球环境历史数据库（HYDE）的粗分辨率人口变化率，在十年间计算出的变化率，用于回溯构建GRUMPv1人口计数网格。通过基于焦点平均值填充的速率单元格，解决了HYDE计算速率的空间范围与GRUMPv1人口数据之间的不匹配。最终，对网格进行了调整，以确保每个国家的人口总数与联合国世界人口前景（2008年修订版）对该国相应年份（1970年、1980年、1990年和2000年）的估计值相符。这些数据不代表2000年之前的人口普查观测值，因此最多只能被视为特定位置人口估计。时间序列内部的人口网格保持一致性，但不建议与其他人口网格（包括GRUMPv1、全球网格化人口版本4（GPWv4）或非SEDAC开发的人口网格）结合用于创建更长的时间序列。这些人口网格作为SEDAC全球按十年划分的估计净迁移网格数据集的输入。