Gridded Population of the World, Version 4 (GPWv4): National Identifier Grid, Revision 11

The Gridded Population of the World, Version 4 (GPWv4): National Identifier Grid, Revision 11 is a raster representation of nation-states in GPWv4 for use in aggregating population data. This data set was produced from the input census Units which were used to create a raster surface where pixels that cover the same census data source (most often a country or territory) have the same value. Note that these data are not official representations of country boundaries; rather, they represent the area covered by the input data. In cases where multiple countries overlapped a given pixel (e.g. on national borders), the pixels were assigned the country code of the input data set which made up the majority of the land area. The data file was produced as a global raster at 30 arc-second (~1 km at the equator) resolution. To enable faster global processing, and in support of research commUnities, the 30 arc-second data were aggregated to 2.5 arc-minute, 15 arc-minute, 30 arc-minute and 1 degree resolutions. Each level of aggregation results in the loss of one or more countries with areas smaller than the cell size of the final raster. Rasters of all resolutions were also converted to polygon shapefiles.

《世界栅格人口，版本 4（GPWv4）：国家标识网格，修订 11》是一项栅格化表示国家在 GPWv4 中的分布，用于汇总人口数据。该数据集由用于创建栅格表面的输入人口普查单元生成，其中覆盖相同人口数据源（通常为国家或地区）的像素具有相同的值。请注意，这些数据并非官方的国家边界表示；相反，它们代表输入数据的覆盖区域。在多个国家重叠特定像素（例如在国家边界上）的情况下，像素被分配了构成大部分陆地面积的国家数据集的代码。数据文件以全球栅格形式生产，分辨率为 30 弧秒（赤道附近约为 1 公里）。为了实现全球处理速度的提升，并支持研究社区，30 弧秒的数据被汇总到 2.5 弧分、15 弧分、30 弧分和 1 度的分辨率。每个汇总级别都会导致一个或多个面积小于最终栅格单元大小的国家丢失。所有分辨率的栅格也被转换为多边形形状文件。