Gridded Population of the World, Version 4 (GPWv4): Land and Water Area, Revision 11

The Gridded Population of the World, Version 4 (GPWv4): Land and Water Area, Revision 11 consists of two rasters that measure surface areas of land and water in square kilometers per pixel. The Land Area raster provides estimates of the land area, excluding permanent ice and water, within each pixel, and was used to calculate the population density rasters. The Water Area raster provides estimates of the water area (permanent ice and water) within each pixel. The sum of land area and water area of a pixel equals the total surface area of that pixel. The data files were produced as global rasters 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.

世界栅格人口第四版（GPWv4）：水陆面积修订版11包含两个栅格，分别以每像素平方千米为单位测算陆地与水域的表面积。陆地面积栅格可估算各像素内不含永久冰与水域的陆地面积，该数据曾用于计算人口密度栅格；水域面积栅格则可估算各像素内的水域（含永久冰与水域）面积。单个像素的陆地面积与水域面积之和，等于该像素的总表面积。本数据集以30角秒（arc-second）分辨率生成全球栅格，赤道处该分辨率对应约1千米的地面距离。为支持全球快速数据处理并服务科研群体，30角秒分辨率的原始数据被聚合为2.5角分（arc-minute）、15角分、30角分以及1度四种分辨率。