The Central African Republic Diamond Database (2018) - Archival ASM and Diamond Occurrences Dataset

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Frequently anticipated questions:

What does this data set describe?

Title:
The Central African Republic Diamond Database (2018) - Archival ASM and Diamond Occurrences Dataset
Abstract:
This GIS dataset is a point shapefile, wherein each point describes the location of a diamond occurrence recorded in a variety of published and unpublished forms. For this purpose,'diamond occurrence' is defined as locations where diamonds have been recovered or observed. Sources of diamond occurrence are diverse and potentially include fieldwork, reports of artisanal mine sites, diamond mining company sample records, geologic maps and mine sites interpreted from satellite imagery acquired prior to January 1, 2013.
Supplemental_Information:
A second dataset, titled "The Central African Republic Diamond Database - Recent ( 2013-2016) Mining Activity" is closely associated with this dataset, and both should be used in describing the geographic distribution of CAR's diamond resources.
  1. How might this data set be cited?
    Chirico, Peter G., DeWitt, Jessica D., Bergstresser, Sarah E., and Clark, Inga E., 2018, The Central African Republic Diamond Database (2018) - Archival ASM and Diamond Occurrences Dataset: 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: 14.462403948899
    East_Bounding_Coordinate: 27.426271135882
    North_Bounding_Coordinate: 10.96233471064
    South_Bounding_Coordinate: 2.3719315539959
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 1964
    Currentness_Reference:
    Publication dates for articles, maps, etc. used as reference to create the dataset
  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:
      Latitude and longitude coordinates, World Geodetic System 1984 (WGS84) Universal Transverse Mercator (UTM) Zone 34 N coordinates
      This is a Point 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 10.0
      Ordinates (y-coordinates) are specified to the nearest 10.0
      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?
    Archival Diamond Occurrences in the Central African Republic
    archival diamond occurrence geographic locations and attributes (Source: USGS Artisanal Diamonds Project)
    OBJECTID
    Unique identifier number for each point record (Source: Automatically named and populated by ESRI ArcGIS 10.4)
    Range of values
    Minimum:1
    Maximum:2604
    Formal codeset
    Codeset Name:Shape
    Codeset Source:ESRI ArcGIS 10.4
    UniqueID
    Non-GIS unique identification code that links each point to the source (map or otherwise) that it came from (Source: USGS Artisanal Diamonds Project) The first 3 letters of the point record's source, followed by a sequential, unique, whole number labeling the record within that source.
    Source
    The author and date of the source data from which the point was collected. (Source: Data source citation) This field describes the author and date of the source from which the point record was collected. Using this information, the source's full citation information may be found in the OFR publication for this work (DeWitt, et al. 2017).
    Source_Dat
    Source Date: The year in which the data source was published. (Source: Data source citation) The publication year of the data source. This column may be sorted to help identify contemporary and older points in the dataset.
    Source_Cat
    Source Category: A generalized descriptor of the type of source from which the point record was collected (Source: USGS Artisanal Diamond Project)
    ValueDefinition
    ArticleTextual document/record, published in a peer-reviewed journal, containing a map with diamond occurrences or a table of diamond occurrence location coordinates.
    Field DataIn Situ observation of diamond occurrences by the USGS or USAID
    MapCartographic product with points or polygons indicating areas of diamond mining
    Map and TextCartographic product with points or polygons indicating areas of diamond mining, accompanied by textual report of mineral resources
    ReportDocumented observations from a mining company or other informal publication
    Satellite ImageryObservation of ASM indicators in very high resolution (VHR) panchromatic or multispectral satellite imagery - see OFR section 'Interpretation of Recent (2013-2016) Mining' for details
    Type
    Observation Type: provides generalized description of the level of detail or accuracy that a point record may have. (Source: USGS Artisanal Diamonds Project)
    ValueDefinition
    ASM SiteIndicates a location at which diamond ASM mining was observed, but without specific information regarding the presence or absence of diamonds at the site
    Field SampleIndicates a location at which detailed observations have been made of surficial geology and/ or diamond resources, typically from a Report
    Diamond OccurrenceGeneric observation indicating a location at which diamonds have been recovered
    Latitude
    Y coordinate, in decimal degrees of WGS 84 for the point record's location (Source: WGS 1984)
    Range of values
    Minimum:-90
    Maximum:90
    Units:decimal degrees
    Longitude
    X coordinate, in decimal degrees of WGS 84 for the point record's location (Source: WGS 1984)
    Range of values
    Minimum:-180
    Maximum:180
    Units:decimal degrees
    N_UTM34N
    Y coordinate, in meters of WGS 84 UTM 34N for the point record's location (Source: WGS 84 UTM 34 N) projected coordinates
    E_UTM34N
    X coordinate, in meters of WGS 84 UTM 34N for the point record's location (Source: WGS 84 UTM 34 N) projected coordinates

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?
    Peter G. Chirico
    U.S. Geological Survey
    12201 Sunrise Valley Dr.
    Reston, VA
    USA

    703-648-6950 (voice)
    pchirico@usgs.gov

Why was the data set created?

These data were collected as part of a larger Diamond Database for the Central African Republic, with the goal of describing the geographic distribution of archival and current diamond occurrences in order to examine links between diamond resources and violent conflicts in the country.

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)
    Locations of historic ASM activity and diamond occurrences were compiled into the Archival Diamond Occurrence point geodatabase from a variety of published and un-published data sources. For this purpose, diamond occurrence is defined as locations where diamonds have been recovered. Source records of historic diamond occurrences are diverse and may include fieldwork, reports of artisanal mine sites, diamond mining company pit sample records, geologic maps and mine sites interpreted from satellite imagery prior to 2013. Each diamond occurrence in the geodatabase was attributed with information identifying the source, the publication year of the source, and the type of diamond occurrence. (i.e. ASM site, field sample, and occurrence). Additional details regarding the compilation of this dataset can be found in the OFR assocaited with the dataset's publication (DeWitt and others, 2018)
  3. What similar or related data should the user be aware of?
    Chirico, Peter G., DeWitt, Jessica D., Bergstresser, Sarah E., and Clark, Inga E., 2018, Recent mining areas 2013-2017: U.S. Geological Survey, Reston, VA.

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)
    Peter G. Chirico
    U.S. Geological Survey
    12201 Sunrise Valley Dr.
    Reston, VA
    USA

    703-648-6950 (voice)
    pchirico@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:
Peter G. Chirico
U.S. Geological Survey
12201 Sunrise Valley Dr.
Reston, VA
USA

703-648-6950 (voice)
pchirico@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 06:46:24 2018