Integrated Hydrological Units of the United Kingdom: Catchments

This dataset is part of Integrated Hydrological Units (IHU) of the UK, a set of geographical reference units for hydrological purposes including river flow measurement and hydrometric data collection. This dataset was derived from the Integrated Hydrological Terrain Model. A Catchment represents the full area upstream from a Section outlet, which is a cell upstream of a confluence of two watercourses with known names. While Sections do not overlap, Catchments can overlap because one Catchment contains Catchments for all upstream Sections. This layer currently covers Great Britain only as no dataset with river geometries and names with suitable detail is available for Northern Ireland.

本数据集隶属于英国综合水文单元（Integrated Hydrological Units, IHU），该类单元是服务于水文工作的地理参考单元，可用于河流流量测量与水文数据采集。本数据集源自综合水文地形模型（Integrated Hydrological Terrain Model）。流域（Catchment）指断面（Section）出口上游的完整区域；而断面出口为位于两条命名已知水道汇流点上游的栅格单元。尽管断面之间互不重叠，但流域可能存在重叠，因为某一流域会包含所有上游断面对应的流域。当前该图层仅覆盖大不列颠地区，原因是北爱尔兰地区暂无具备足够详细精度的河流几何形态与名称数据集。