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

Metadata Updated: October 10, 2019

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. af_cti_3_2.zip 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

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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Dates

Metadata Date May 23, 2017
Metadata Created Date July 8, 2019
Metadata Updated Date October 10, 2019
Reference Date(s) January 1, 2017 (publication)
Frequency Of Update notPlanned
Frequency Of Update notPlanned

Metadata Source

Harvested from DOI CKAN Harvest Source

Additional Metadata

Resource Type Dataset
Metadata Date May 23, 2017
Metadata Created Date July 8, 2019
Metadata Updated Date October 10, 2019
Reference Date(s) January 1, 2017 (publication)
Responsible Party U.S. Geological Survey, Southwest Region (Point of Contact)
Contact Email
Access Constraints Use Constraints: None. Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations., Access Constraints: None
Bbox East Long 77.6024999999
Bbox North Lat 37.5608333338
Bbox South Lat -54.465
Bbox West Long -25.3624999996
Coupled Resource
Frequency Of Update notPlanned
Guid
Harvest Object Id 71f9955b-50b2-48a8-8516-b7df5b273cda
Harvest Source Id 34ce571b-cb98-4e0b-979f-30f9ecc452c5
Harvest Source Title DOI CKAN Harvest Source
Licence This database, identified as "Hydrologic Derivatives for Modeling and Analysis (HDMA)", has been approved for release by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the database is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.
Metadata Language
Metadata Type geospatial
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester true

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