WWF HydroSHEDS Drainage Direction, 3 Arc-Seconds (WWF/HydroSHEDS/03DIR)

HydroSHEDS is a mapping product that provides hydrographic information for regional and global-scale applications in a consistent format. It offers a suite of geo-referenced datasets (vector and raster) at various scales, including river networks, watershed boundaries, drainage directions, and flow accumulations. HydroSHEDS is based on elevation data obtained in 2000 by NASA’s Shuttle Radar Topography Mission (SRTM).

This drainage direction dataset defines the direction of flow from each cell in the conditioned DEM to its steepest down-slope neighbor. Values of drainage direction vary from 1 to 128. All final outlet cells to the ocean are flagged with a value of 0. All cells that mark the lowest point of an endorheic basin (inland sink) are flagged with a value of -1. The drainage direction values follow the convention adopted by ESRI’s flow direction implementation: 1=E, 2=SE, 4=S, 8=SW, 16=W, 32=NW, 64=N, 128=NE.

This dataset is at 3 arc-second resolution. The datasets available at 3 arc-seconds are the Void-Filled DEM, Hydrologically Conditioned DEM, and Drainage (Flow) Direction.