Data terms

HydroSHEDS (rivers, basins and terrain)

River lines, the river network, Strahler order, discharge and drainage areas come from HydroRIVERS v1.0; the shaded drainage basins are merged from HydroBASINS v1c level 12; the hillshade and elevations come from the HydroSHEDS void-filled DEM. All are used under the HydroSHEDS v1 License Agreement.

This product Widyan incorporates data from the HydroSHEDS version 1 database which is © World Wildlife Fund, Inc. (2006-2022) and has been used herein under license. WWF has not evaluated the data as altered and incorporated within Widyan, and therefore gives no warranty regarding its accuracy, completeness, currency or suitability for any particular purpose. Portions of the HydroSHEDS v1 database incorporate data which are the intellectual property rights of © USGS (2006-2008), NASA (2000-2005), ESRI (1992-1998), CIAT (2004-2006), UNEP-WCMC (1993), WWF (2004), Commonwealth of Australia (2007), and Her Royal Majesty and the British Crown and are used under license. The HydroSHEDS v1 database and more information are available at https://www.hydrosheds.org.

Citation: Lehner, B., Grill G. (2013): Global river hydrography and network routing: baseline data and new approaches to study the world's large river systems. Hydrological Processes, 27(15): 2171–2186.

Under that license, the data on this site is provided only as part of the Widyan map. You may not extract it and redistribute it as a stand-alone dataset, and it comes with no warranty of accuracy, completeness or fitness for any purpose. To use HydroSHEDS data yourself, get it from hydrosheds.org under its own terms.

OpenStreetMap (names, seasonality, dams)

River names in Arabic, French and Tamazight, seasonal flags, dams and reservoirs are © OpenStreetMap contributors, available under the Open Database License (ODbL) 1.0. Snapshot of 2026-10-30. The OSM-derived data is kept in its own files (osm-rivers.json, dams.json), keyed by HydroRIVERS reach ID, and those files are available under the ODbL. See openstreetmap.org/copyright.

Natural Earth (outline, cities)

The country outline (Morocco point-of-view edition, including the Sahara) and city locations come from Natural Earth 5.1.1, which is in the public domain. Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com.

Gaps and accuracy

Where a source has no value, Widyan shows “—” instead of an estimate. Names are matched from OpenStreetMap to HydroRIVERS by geometry; reaches without a confident match stay unnamed. Seasonality is only known where OpenStreetMap records it; other reaches are drawn as permanent. Lengths come from a 15″ raster river network and can differ from official figures.

Privacy

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