The Central African Republic Diamond Database (2018)

Identification_Information:

Citation:

Citation_Information:

Originator: Jessica D. DeWitt
Originator: Peter G. Chirico
Originator: Sarah E. Bergstresser
Originator: Inga E. Clark
Publication_Date: 2018
Title:

The Central African Republic Diamond Database (2018) - Watersheds of Large Rivers

Geospatial_Data_Presentation_Form: GIS dataset
Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Online_Linkage: https://doi.org/10.5066/F7FB51T5
Larger_Work_Citation:

Citation_Information:

Originator: Jessica D. DeWitt
Originator: Peter G. Chirico
Originator: Sarah E. Bergstresser
Originator: Inga E. Clark
Publication_Date: 2018
Title:

The Central African Republic Diamond Database – A Geodatabase of Archival Diamond Occurrences and Areas of Recent Artisanal and Small-scale Diamond Mining

Geospatial_Data_Presentation_Form: On File Report
Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Description:

Abstract:

This vector GIS dataset contains polygons that delimit the watershed boundaries of 6th order streams in the Central African Republic. It was derived from the 30m Hydrologically Corrected Digital Elevation Model (DEM) of the Central African Republic using the tools in ArcGIS 10.4. In brief, this process entails calculation of flow direction and flow accumulation raster datasets from the DEM; classification of the flow accumulation raster into gridcells representing the location of a stream (based on the blue lines of the 1:250,000 Joint Operations Graphic for CAR); calculation of the Strahler Stream Order; reclassification of the stream raster to remove lower order stream segments (orders 1-5); calculation of a stream link raster, which entailed enumeration of the reclassified stream's intersections; and calculation of watershed areas based on the stream link raster and the flow direction raster. Details regarding these procedures can be found in DeWitt and others (2018).

Purpose:

The purpose of this dataset is to delimit the watershed boundaries of large rivers in the Central African Republic.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2017

Currentness_Reference: publication date

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: 14.721679683312
East_Bounding_Coordinate: 27.202148432813
North_Bounding_Coordinate: 10.746539462399
South_Bounding_Coordinate: 2.8987157288129

Keywords:

Theme:

Theme_Keyword_Thesaurus: Alexandria Digital Library Feature Type Thesaurus
Theme_Keyword: drainage basins

Place:

Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: Central African Republic

Access_Constraints: none
Use_Constraints:

Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Jessica D. DeWitt
Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: mailing and physical
Address: 12201 Sunrise Valley Dr.
City: Reston
State_or_Province: VA
Postal_Code: 20192
Country: USA

Contact_Voice_Telephone: 703-648-6926
Contact_Electronic_Mail_Address: jdewitt@usgs.gov

Data_Set_Credit:

U.S. Department of State, U.S. Agency for International Development

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report: No formal attribute accuracy tests were conducted

Logical_Consistency_Report: No formal logical accuracy tests were conducted
Completeness_Report:

Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report: No formal positional accuracy tests were conducted

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report: No formal positional accuracy tests were conducted

Lineage:

Process_Step:

Process_Description:

This watershed dataset was derived from the 30m Hydrologically Corrected Digital Elevation Model (DEM) of the Central African Republic using the tools in ArcGIS 10.4. In brief, this process entailed calculation of flow direction and flow accumulation grids from the DEM; classification of the flow accumulation grid into cells representing the location of a stream, resulting in a 'streams raster'; calculation of the Strahler Stream Order for the stream raster; reclassification of the stream grid to include only high order streams (orders 6-9); calculation of a stream link grid, which entailed enumeration of the reclassified stream's intersections; and calculation of watershed areas based on the stream link grid and the flow direction grid. Details regarding these procedures can be found in DeWitt and others (2017).

Process_Date: 2017

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference: This dataset covers the extent of the Central African Republic
Direct_Spatial_Reference_Method: Vector

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Transverse Mercator
Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: 21.0
Latitude_of_Projection_Origin: 0.0
False_Easting: 500000.0
False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:

Abscissa_Resolution: 30.0
Ordinate_Resolution: 30.0

Planar_Distance_Units: METERS

Geodetic_Model:

Horizontal_Datum_Name: D_WGS_1984
Ellipsoid_Name: WGS_1984
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257223563

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: CAR_Watersheds_order6_streams
Entity_Type_Definition:

Each row indicates a watershed polygon within Central African Republic

Entity_Type_Definition_Source: All values in the dataset were calculated in ArcGIS 10.4

Attribute:

Attribute_Label: Area_km2
Attribute_Definition: Area of the watershed polygon in square kilometers
Attribute_Definition_Source: Area value calculated by ArcGIS 10.4
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.002192
Range_Domain_Maximum: 17797.77362
Attribute_Units_of_Measure: square kilometers

Attribute:

Attribute_Label: Shape_Length
Attribute_Definition: length of the perimeter of the watershed polygon, in meters
Attribute_Definition_Source: Length value auto-calculated by ArcGIS 10.4
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 237.992614
Range_Domain_Maximum: 1492847.288358
Attribute_Units_of_Measure: meters

Attribute:

Attribute_Label: Shape_Area
Attribute_Definition: Area of the watershed polygon in square meters
Attribute_Definition_Source: Length value auto-calculated by ArcGIS 10.4
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 2192.352385
Range_Domain_Maximum: 17797773620.396732
Attribute_Units_of_Measure: square meters

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Jessica D. DeWitt
Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: mailing and physical
Address: 12201 Sunrise Valley Dr.
City: Reston
State_or_Province: VA
Postal_Code: 20192
Country: USA

Contact_Voice_Telephone: 703-648-6926
Contact_Electronic_Mail_Address: jdewitt@usgs.gov

Distribution_Liability:

Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research.

Technical_Prerequisites:

This dataset is formatted as a feature class in an ESRI geodatabase. It requires the user to have geospatial software such as ESRI ArcGIS, Blue Marble Global Mapper, Que GIS, GRASS, or other GIS software.

Metadata_Reference_Information:

Metadata_Date: 20180405
Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Jessica D. DeWitt
Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: mailing and physical
Address: 12201 Sunrise Valley Dr.
City: Reston
State_or_Province: VA
Postal_Code: 20192
Country: USA

Contact_Voice_Telephone: 703-648-6926
Contact_Electronic_Mail_Address: jdewitt@usgs.gov

Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998

The Central African Republic Diamond Database (2018) - Watersheds of Large Rivers

Metadata: