Hydrologic Derivatives for Modeling and Analysis (HDMA) database -- Greenland

This contains the Greenland portion of the Hydrologic Derivatives for Modeling and Analysis (HDMA) database. The HDMA database provides comprehensive and consistent global coverage of raster and vector topographically derived layers, including raster layers of digital elevation model (DEM) data, flow direction, flow accumulation, slope, and compound topographic index (CTI); and vector layers of streams and catchment boundaries. The coverage of the data is global (-180º, 180º, -90º, 90º) with the underlying DEM being a hybrid of three datasets: HydroSHEDS (Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales), Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010) and the Shuttle Radar Topography Mission (SRTM). For most of the globe south of 60º North, the raster resolution of the data is 3-arc-seconds, corresponding to the resolution of the SRTM. For the areas North of 60º, the resolution is 7.5-arc-seconds (the smallest resolution of the GMTED2010 dataset) except for Greenland, where the resolution is 30-arc-seconds. The streams and catchments are attributed with Pfafstetter codes, based on a hierarchical numbering system, that carry important topological information.

本数据集包含建模与分析水文衍生数据集（Hydrologic Derivatives for Modeling and Analysis, HDMA）的格陵兰岛子集数据。HDMA数据库提供覆盖全球的一致性栅格与矢量地形衍生图层，其中栅格图层包含数字高程模型（DEM）数据、流向、汇流累积量、坡度以及复合地形指数（CTI）；矢量图层则涵盖水系与流域边界。该数据集的全球覆盖范围为(-180°，180°，-90°，90°)，其基础DEM由三类数据集融合生成：多尺度航天飞机高程衍生水文数据与地图集（HydroSHEDS）、2010年全球多分辨率地形高程数据（GMTED2010）以及航天飞机雷达地形测绘任务（SRTM）。在全球北纬60°以南的绝大多数区域，该数据集的栅格分辨率为3角秒，与SRTM的分辨率保持一致；北纬60°以北的其余区域分辨率为7.5角秒（即GMTED2010数据集的最低分辨率），但格陵兰岛地区除外，其分辨率为30角秒。水系与流域边界图层标注有基于层级编号系统的普发夫斯特特编码（Pfafstetter codes），该编码承载了重要的拓扑信息。