| Summary: | The Global River Topology (GRIT) is a vector-based, global river network that not only represents the tributary components of the global drainage network but also the distributary ones, including multi-thread rivers, canals and delta distributaries. It is also the first global hydrography (excl. Antarctica and Greenland) produced at 30m raster resolution. It is created by merging Landsat-based river mask (GRWL) with elevation-generated streams to ensure a homogeneous drainage density outside of the river mask (rivers narrower than approx. 30m). Crucially, it uses a new 30m digital terrain model (FABDEM, based on TanDEM-X) that shows greater accuracy over the traditionally used SRTM derivatives. After vectorisation and pruning, directionality is assigned by a combination of elevation, flow angle, heuristic and continuity approaches (based on RivGraph). The network topology (lines and nodes, upstream/downstream IDs) is available as layers and attribute information in the GeoPackage files (readable by QGIS/ArcMap/GDAL). Regions Vector files are provided in 6 continental regions with the following codes: AF - Africa AS - Asia EU - Europe NA - North America SA - South America SP - South Pacific/Australia The domain polygons (GRITv04_domain_GLOBAL.gpkg.zip) provide 60 subcontinental catchment groups that are available as vector attributes. They allow for more fine-grained subsetting of data (e.g. with ogr2ogr --where). Network segments Lines between inlet, outlet, confluence and bifurcation nodes. Files have lines and nodes layers. Attribute description of lines layer Name Data type Description cat integer domain internal feature ID global_id integer global river segment ID, same as FID catchment_id integer global catchment ID upstream_node_id integer global segment node ID at upstream end of line downstream_node_id integer global segment node ID at downstream end of line upstream_line_ids text comma-separated list of global river segment IDs connecting at upstream end of line downstream_line_ids text comma-separated ...
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