Global Topographic 30 Arc-Second Digital Elevation Model: Released 1996

GTOPO30 is a global digital elevation model (DEM) with a horizontal grid spacing of 30 arc seconds (approximately 1 kilometer). GTOPO30 was derived from several raster and vector sources of topographic information. For easier distribution, GTOPO30 has been divided into tiles which can be selected from the map shown above. Detailed information on the characteristics of GTOPO30 including the data distribution format, the data sources, production methods, accuracy, and hints for users, is found in the GTOPO30 README file.

GTOPO30是一款全球数字高程模型（DEM, Digital Elevation Model），水平网格间距为30角秒（约1千米）。该数据集基于多套栅格与矢量地形信息源构建而成。为便于分发，GTOPO30已被分割为若干瓦片，用户可通过上方展示的地图选取所需瓦片。关于GTOPO30的各项特征细节，包括数据分发格式、数据源、制作流程、精度以及用户使用提示等，均可在GTOPO30的README文件中查阅。