The Central African Republic Diamond Database (2018) - Streamlines (DEM-Derived) with Names and Stream Order

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Frequently anticipated questions:

What does this data set describe?

Title:
The Central African Republic Diamond Database (2018) - Streamlines (DEM-Derived) with Names and Stream Order
Abstract:
GIS polyline dataset which describes stream lines in the Central African Republic. This dataset was derived automatically from the hydrologically corrected 30m DEM published with the Central African Republic Diamond Database (2017) using ArcGIS 10.4 hydrologic tool. In brief, the workflow that created the streams included calculation of flow direction, flow accumulation, reclassification using a threshold of 7,000 cells, stream order, and finally conversion from raster data type to vector (polyline) data type. Streamlines have the Strahler stream order value as an attribute, as well as the name of the stream reach determined from reference maps (see DeWitt and others, 2018 for more details).
  1. How might this data set be cited?
    DeWitt, Jessica D., Bergstresser, Sarah E., Chirico, Peter G., and Clark, Inga E., 2018, The Central African Republic Diamond Database (2018) - Streamlines (DEM-Derived) with Names and Stream Order: U.S. Geological Survey, Reston, VA.

    Online Links:

    This is part of the following larger work.

    DeWitt, Jessica D., Chirico, Peter G., Bergstresser, Sarah E., and Clark, Inga E., 2018, The Central African Republic Diamond Database – A Geodatabase of Archival Diamond Occurrences and Areas of Recent Artisanal and Small-scale Diamond Mining: U.S. Geological Survey, Reston, VA.

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: 14.150390620845
    East_Bounding_Coordinate: 27.861328120298
    North_Bounding_Coordinate: 11.393450325418
    South_Bounding_Coordinate: 2.5036481499899
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2017
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: GIS data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference:
      The dataset exists within the extent of the Central African Republic.
      This is a Vector data set.
    2. What coordinate system is used to represent geographic features?
      The map projection used is Transverse Mercator.
      Projection parameters:
      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 coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 30.0
      Ordinates (y-coordinates) are specified to the nearest 30.0
      Planar coordinates are specified in METERS
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    CAR_streamlines
    attribute table associated with GIS vector dataset (Source: Artisanal Mining Project)
    NAME
    Name of the stream or river reach, if available; recorded from reference maps such as the U.S. Army Corps of Engineers Joint Operation Graphic (JOG) 1:250,000 scale maps. (Source: reference maps) text field contains the name of the stream or river reach, if available.
    Stream_order
    value indicates the Strahler Stream Order for each stream reach polyline segment; (Source: calculated by ArcGIS 10.4 Stream Order tool)
    ValueDefinition
    1First order stream, typically indicating an ephemeral or sometimes-dry stream reach that is a tributary to a larger stream.
    Shape_length
    the length of the stream reach, in meters (Source: calculated by ArcGIS 10.4)
    Range of values
    Minimum:0.417485
    Maximum:14491.537034
    Units:meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
    U.S. Department of State, U.S. Agency for International Development
  3. To whom should users address questions about the data?
    Jessica D. DeWitt
    U.S. Geological Survey
    12201 Sunrise Valley Dr.
    Reston, VA
    USA

    703-648-6926 (voice)
    jdewitt@usgs.gov

Why was the data set created?

The purpose of this dataset is to describe the locations of streams in the Central African Republic. Streamlines also contain attributes describing the Strahler Stream Order and the name of the stream (if available).

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2017 (process 1 of 1)
    GIS polyline dataset which describes stream lines in the Central African Republic. This dataset was derived automatically from the hydrologically corrected 30m DEM published with the Central African Republic Diamond Database (2017) using ArcGIS 10.4 hydrologic tools. Processing steps included calculation of flow direction, flow accumulation, reclassification using a threshold of 7,000 cells (see DeWitt et al. 2017 for more details), stream order, and finally conversion from raster data type to vector (polyline) data type. Streamlines have the name of the stream reach determined from reference maps (see DeWitt et al. 2017 for more details) as an attribute, as well as the Strahler stream order value.
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    No formal attribute accuracy tests were conducted
  2. How accurate are the geographic locations?
    No formal positional accuracy tests were conducted
  3. How accurate are the heights or depths?
    No formal positional accuracy tests were conducted
  4. Where are the gaps in the data? What is missing?
    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.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
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.
  1. Who distributes the data set? (Distributor 1 of 1)
    Jessica D. DeWitt
    U.S. Geological Survey
    12201 Sunrise Valley Dr.
    Reston, VA
    USA

    703-648-6926 (voice)
    jdewitt@usgs.gov
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    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.

Who wrote the metadata?

Dates:
Last modified: 05-Apr-2018
Metadata author:
Jessica D. DeWitt
U.S. Geological Survey
12201 Sunrise Valley Dr.
Reston, VA
USA

703-648-6926 (voice)
jdewitt@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Generated by mp version 2.9.47 on Thu Apr 5 06:52:23 2018