Shaded Relief Image of the Caribbean Region (shadedrelief.jpg)

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Frequently-anticipated questions:


What does this data set describe?

Title: Shaded Relief Image of the Caribbean Region (shadedrelief.jpg)
Abstract:
This composite shaded relief image dataset depicts generalized bathymetry and topography of the Caribbean region.
Supplemental_Information:
The image was created for asthetic purposes only and should not be used for analysis or navigation. Check the data quality portion of this document before using the image in other projects. Exports between ArcGIS and graphics programs may have degraded original data quality, while georeferencing may have affected original horizontal accuracy of data. A smooth gradient technique was used on data to emphasize color and variability of surfaces.
  1. How should this data set be cited?

    Christopher D. French and Chris, USGS, Denver, CO, 20040000, Shaded Relief Image of the Caribbean Region (shadedrelief.jpg): U.S. Geological Survey, Central Energy Resources Team, Denver, Colorado.

    Online Links:

    This is part of the following larger work.

    Christopher D. French and Chris, USGS, Denver, CO, 20040000, Open-file report 97-470-K "Map Showing Geology, Oil and Gas Fields, and Geologic Provinces of the Caribbean Region": U.S. Geological Survey, Open-file Report OFR-97-470-K, U.S. Geological Survey, Central Energy Resources Team, Denver, Colorado, USA.

    Online Links:

    Other_Citation_Details:
    Open File Report 97-470-K is one of a series of continental-scale geologic maps of the world being published on CD-ROM by the U.S. Geological Survey World Energy Project.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -92.990940
    East_Bounding_Coordinate: -57.041180
    North_Bounding_Coordinate: 28.005768
    South_Bounding_Coordinate: 7.054612

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 2003
    Currentness_Reference: publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: raster digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 8376 x 14375 x 1, type Pixel

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.

  7. How does the data set describe geographic features?


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?

  3. To whom should users address questions about the data?

    Christopher J. Schenk
    U.S. Geological Survey, Central Energy Resources Team
    Caribbean Regional Coordinator for World Energy Project
    U.S. Geological Survey, Box 25046, MS 939, Denver Federal Center
    Denver, Colorado 80225-0046
    USA

    303-236-5796 (voice)
    303-236-0459 (FAX)
    schenk@usgs.gov


Why was the data set created?

The dataset was created as a means to display shaded relief information in the cartographic products for U.S. Geological Survey Open-File Report 97-470-K, Map Showing Geology, Oil and Gas Fields, and Geologic Provinces of the Caribbean Region. The image is a composite of two individual datsets: 30 arc-second topographic grid data (GTOPO30) and 1- minute bathymetric grid data (GEBCO). The image was considered suitable for this type of display at a scale of 1:2,670,000. It is provided for others who may wish to compile a mapping project in the region.


How was the data set created?

  1. From what previous works were the data drawn?

    USGS-GTOPO30 (source 1 of 2)
    U.S. Geological Survey - EROS Data Center, Unknown, 1-Degree USGS Digital Elevation Models: GTOPO30 (Global 30 Arc-Second Elevation Data Set) GTOPO30, USGS, Sioux Falls, SD.

    Online Links:

    Type_of_Source_Media: online-FTP
    Source_Contribution:
    Topographic shaded relief derived from GTOPO30 digital elevation model.

    BODC-GEBCO (source 2 of 2)
    British Oceanographic Data Cetre, 2003, General Bathymetric Chart of the Oceans (GEBCO): General Bathymetric Chart of the Oceans 1903-2003 Centenary Edition, British Oceanographic Data Centre, Liverpool, England.

    Online Links:

    Other_Citation_Details:
    Full citiation for publication: IOC, IHO, and BODC, 2003, "Centenary Edition of the GEBCO Digital Atlas", published on CD-ROM on behalf of the Intergovernmental Oceanographic Commission and the Hydrographic Organization as part of the General Bathymetric Chart of the Oceans; British Oceanographic Data Centre, Liverpool.
    Type_of_Source_Media: CD-ROM
    Source_Contribution: Bathymetric depth grids.

  2. How were the data generated, processed, and modified?

    Date: Jun-2003 (process 1 of 6)
    Clipped DEM datasets to project extent.

    Data sources used in this process:

    • USGS

    Date: Jun-2003 (process 2 of 6)
    Created hillshade for GTOPO30 DEM with azimuth of 315 degrees and sun angle of 45 degrees. All settings left at default.

    Data sources used in this process:

    • USGS

    Date: Jun-2003 (process 3 of 6)
    Opened GEBCO and GTOPO30 shaded relief layers in ArcGIS ArcMap and exported at high-resolution setting in PDF format.

    Data sources used in this process:

    • USGS

    Date: Jul-2003 (process 4 of 6)
    Exported DEM layer in grayscale for use as transparent gradient overlay.

    Data sources used in this process:

    • USGS

    Date: Jul-2003 (process 5 of 6)
    Used Adobe Photoshop to add smooth color gradient to DEM layer with transparency and drape over the shaded relief layers. Exported composite as JPEG image with highest quality setting (12).

    Data sources used in this process:

    • USGS

    (process 6 of 6)
    Georeferenced image in ArcMap 8.3 with the georeferencing toolbar. Image was able to be referenced with only 4 control points using a 1st order polynomial transformation.

    Data sources used in this process:

    • USGS

  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?

    Attributes only convey RGB values of individual cells. No other attributes were added.

  2. How accurate are the geographic locations?

    No horizontal positional accuracy quantified. Accuracy largely based on original source data. A brief description is provided below.
    Original 30 arc-second global topographic (GTOPO30) data accuracy varies by location because sources are chosen on the best available for the area, and use a total of eight sources worldwide. Sources could be raster or vector, with more accuracy claimed from the raster sources. The exact source(s) of the data for the extent shown in the Caribbean region were not determined. Horizontal accuracy is considered to be no greater than the spatial resolution of 1000 meters.
    The second dataset is a compilation of bathymetric data provided by the British Oceanographic Data Centre in their General Bathymetric Chart of the Oceans (GEBCO) product. A wide variety of sources and scales were used by the data provider to digitize contours for use in the 1-minute grid product. Horizontal accuracy is considered to be no greater than the spatial resolution of 2000 meters. The graphical merging process, where GEBCO 1-minute data were combined with GTOPO30 topographic data, introduced additional error through exporting to a compressed JPEG image format. The JPEG format uses a lossy compression technique to reduce file size at the sacrifice of image quality.

  3. How accurate are the heights or depths?

    No elevation or depth information provided in data.

  4. Where are the gaps in the data? What is missing?

    Complete

  5. How consistent are the relationships among the observations, including topology?

    Dataset is a compilation of two published datasets which are also compilations from various sources. Accuracy depends upon the stated accuracies of original data in addition to introduced error from merging processes.


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: None

  1. Who distributes the data set? (Distributor 1 of 1)

    USGS Information Services
    Box 25286 Denver Federal Center
    Denver, Colorado 80225
    USA

    1-888-ASK-USGS (voice)
    303.202.4693 (FAX)
    ask@usgs.gov

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    This pubilication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
    Although all data and software published on this CD-ROM are used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the U.S. Geological Survey as to the accuracy of the data and related materials and (or) the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data, software, or related materials.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 22-Mar-2004
Last Reviewed: 2004
Metadata author:
Christopher French
U.S. Geological Survey, Central Energy Resources Team, Data Management Project
GIS Specialist
U.S. Geological Survey, Box 25046, MS 939, Denver Federal Center
Denver, Colorado 80225
USA

303-236-1655 (voice)
datamgt@usgs.gov

Contact_Instructions:
For inquiries regarding this document, please include the metadata contact person's name, dataset name, and publication series and number.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


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