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Compound Topographic Index (CTI) from the Hydrologic Derivatives for Modeling and Analysis (HDMA) database -- Africa

Metadata Updated: July 6, 2024

This data set contains the Compound Topographic Index (CTI) for Africa from the Hydrologic Derivatives for Modeling and Analysis (HDMA) database. The CTI data were developed and distributed by processing units. There are 19 processing units for Africa. The distribution files have the number of the processing unit appended to the end of the zip file name (e.g. contains the CTI data for unit 3-2). 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 data sets: 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 data set) 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.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date June 1, 2023
Metadata Updated Date July 6, 2024

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date July 6, 2024
Publisher U.S. Geological Survey
Identifier USGS:591f6cf9e4b0ac16dbdde1c5
Data Last Modified 20200814
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id 60823155-d0cf-4ad2-be94-c4cb2b59fb6a
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -25.3624999996,-54.465,77.6024999999,37.5608333338
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash e65b2851c4ec5ee5c1e0ab3f39417abacfb3b2196d691aaecb7d12a81c426b3d
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -25.3624999996, -54.465, -25.3624999996, 37.5608333338, 77.6024999999, 37.5608333338, 77.6024999999, -54.465, -25.3624999996, -54.465}

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