Shaded-relief TIFF image of a portion of the Coastal Relief Model off the west coast of Florida

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Frequently-anticipated questions:

What does this data set describe?

Shaded-relief TIFF image of a portion of the Coastal Relief Model off the west coast of Florida
The National Grids that integrate land and seafloor elevations are needed by planners using LIS/GIS software to manage the US coastal zone, which encompasses the coastal states out to the country's 200-mile offshore limit. Geophysical Data Center (NGDC) is addressing this need by assembling a gridded database that merges the US Geological Survey 3-arc-second DEMs with a vast compilation of hydrographic soundings collected by the National Ocean Service and various academic institutions. The principal component of the database is 3-arc-second elevation grids, of areas 1degree in longitude by 1degree in latitude, in which elevations are resolved to 1/10 of a meter. The database also includes grids containing the number of soundings enclosed by each cell in the offshore areas of the elevation grids, and images of both the elevation and sounding density grids. The latter are in common graphic formats that can be displayed by a range of UNIX-based and personal computer software.
  1. How should this data set be cited?

    Cross, VeeAnn A. , 2005, Shaded-relief TIFF image of a portion of the Coastal Relief Model off the west coast of Florida:.

    Online Links:

    This is part of the following larger work.

    Cross, VeeAnn A. , Twichell, David C. , Halley, Robert B. , Ciembronowicz, Kate T. , Jarrett, Bret D. , Hammar-Klose, Erika S. , Hine, Al C. , Locker, Stan D. , and Naar, Dave F. , 2005, GIS Compilation of Data Collected from the Pulley Ridge Deep Coral Reef Region: Open-File Report 2005-1089, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -87.000000
    East_Bounding_Coordinate: -79.999195
    North_Bounding_Coordinate: 31.000805
    South_Bounding_Coordinate: 24.000000

  3. What does it look like?

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

    Calendar_Date: 2001
    Currentness_Reference: publication date

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

    Geospatial_Data_Presentation_Form: remote-sensing image

  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 8401 x 8401 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. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      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?


    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.





    The Coastal Relief Model TIFF image off the coast of Florida, on the Florida shelf, is a shaded relief image. A shaded relief image is produced by applying an artificial light source to elevation (topographic or bathymetric) data. The azimuth, elevation, and vertical exaggeration are specified. The light source produces shadows within the imagery, as if the sun were shinning upon the region. Applying an artificial light source to elevation data, yields an image that is more easily interpreted by the end-user.

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?

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)

Why was the data set created?

The Coastal The TIFF image generated from the Coastal Relief Model provides a base map for Geographic Information System (GIS) database.

How was the data set created?

  1. From what previous works were the data drawn?

    NGDC CRM, Vol. 3 (source 1 of 1)
    National Oceanic and Atmospheric Administration, 2001, Coastal Relief Model, Florida and Eastern Gulf of Mexico, Vol. 3.

    Online Links:

    Type_of_Source_Media: CD-ROM
    A portion of Vol. 3 was used to create the TIFF image of the Gulf of Mexico off the west coast of Florida.

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

    Date: 2005 (process 1 of 1)
    The desired Coastal Relief Model data were extracted from volume 3 in ESRI ASCII format, and then converted to an ESRI grid. Using the ArcMap Spatial Analysis extension, a hillshade was then created from the ESRI grid file. After creating a desirable color scheme, the ESRI grid file and hillshade were combined using the ArcView extension grid-to-image converter tool (downloaded from to create a TIFF image file and world file.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)

  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?

  2. How accurate are the geographic locations?

    The horizontal accuracy of the soundings is generally 30 m, but it can vary from as fine as 15 m in ports and estuaries to as coarse as 75 m in the offshore areas.

  3. How accurate are the heights or depths?

    The vertical accuracy of the soundings is 0.3 m in 0 - 20 m of water, 1.0 m in 20 - 100 m of water, and 1% of the water depth in 100 m of water.

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

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

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
The USGS asks to be referenced in any use of the data. These data are not intended for use in navigation.

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

    David C. Twichell
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)

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

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    Although this data set and its lineage have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data or its related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related items. Users must assume responsibility for the proper use of these data. The data should not be used at resolutions for which they are not intended. The data have not been reviewed for conformity with U.S. Geological Survey editorial standards, or the North American Stratigraphic code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 12-May-2005
Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.6 on Fri May 13 12:17:39 2005