# NGDC_CRM - NGDC Coastal Relief Model image of the project area offshore of Grand Strand, South Carolina (GeoTIFF)

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#### Frequently-anticipated questions:

- What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
- Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
- Why was the data set created?
- How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
- How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
- Who wrote the metadata?

### What does this data set describe?

Title:
  NGDC_CRM - NGDC Coastal Relief Model image of the project area offshore of Grand Strand, South Carolina (GeoTIFF)
Abstract:
  In 1999, the USGS, in partnership with the South Carolina Sea Grant Consortium, began a study to investigate processes affecting shoreline change along the northern coast of South Carolina, focusing on the Grand Strand region. Previous work along the U.S. Atlantic coast shows that the structure and composition of older geologic strata located seaward of the coast heavily influences the coastal behavior of areas with limited sediment supply, such as the Grand Strand. By defining this geologic framework and identifying the transport pathways and sinks of sediment, geoscientists are developing conceptual models of the present-day physical processes shaping the South Carolina coast. The primary objectives of this research effort are: 1) to provide a regional synthesis of the shallow geologic framework underlying the coastal upland, shoreface and inner continental shelf, and define its role in coastal evolution and modern beach behavior; 2) to identify and model the physical processes affecting coastal ocean circulation and sediment transport, and to define their role in shaping the modern shoreline; and 3) to identify sediment sources and transport pathways; leading to construction of a regional sediment budget.

1. How should this data set be cited?

   > U.S. Geological Survey, 2007, NGDC_CRM - NGDC Coastal Relief Model image of the project area offshore of Grand Strand, South Carolina (GeoTIFF): Open-File Report 2005-1346, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

   > Online Links:

   > - <http://pubs.usgs.gov/of/2005/1346/ArcGIS/NGDC/ngdc_crm.zip>

   This is part of the following larger work.

   > Baldwin, W.E., Denny, J.F., Schwab, W.C., Gayes, P.T., Morton, R.A., and Driscoll, N.W., 2007, Geologic Framework Studies of South Carolina's Long Bay from Little River Inlet to Winyah Bay, 1999-2003; geospatial data release: Open-File Report 2005-1346, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

   > Online Links:

   > - <http://pubs.usgs.gov/of/2005/1346/>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -80.176050
   East_Bounding_Coordinate: -76.737177
   North_Bounding_Coordinate: 35.290700
   South_Bounding_Coordinate: 32.707831

3. What does it look like?

   <http://pubs.usgs.gov/of/2005/1346/images/ngdc_crm.jpg> (JPEG)
     JPG image of NGDC coastal relief model

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 2974 x 3312 x 1, type Pixel

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
        UTM_Zone_Number: 17
        Transverse_Mercator:
          Scale_Factor_at_Central_Meridian: 0.999600
          Longitude_of_Central_Meridian: -81.000000
          Latitude_of_Projection_Origin: 0.000000
          False_Easting: 500000.000000
          False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 93.872650
      Ordinates (y-coordinates) are specified to the nearest 93.857165
      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 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.

7. How does the data set describe geographic features?

   Entity_and_Attribute_Overview:
     The Coastal Relief Model TIFF image of the South Carolina is a color-coded image.
   Entity_and_Attribute_Detail_Citation: NGDC

### Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

   - U.S. Geological Survey

2. Who also contributed to the data set?

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

   Jane Denny
   U.S. Geological Survey
   Geologist
   384 Woods Hole Rd.
   Woods Hole, MA 02543-1598
   USA

   (508) 548-8700 x2311 (voice)
   (508) 457-2310 (FAX)
   jdenny@usgs.gov

### Why was the data set created?

> The GeoTIFF image of the coastal region of Grand Strand, South Carolin was generated from the Coastal Relief Model to provide a basemap of the project area for the Geographic Information System (GIS) database.

### How was the data set created?

1. From what previous works were the data drawn?

   NGDC Coastal Relief Model, U.S. Southeast Atlantic, vol.2, 2001 (source 1 of 1)

     > National Oceanic and Atmospheric Administration (NOAA), 2001, Coastal Relief Model, U.S. Southeast Atlantic, Vol. 2, 2001: National Oceanic and Atmospheric Administration (NOAA), National Geophysical Data Center (NGDC), Boulder, Colorado.

     > Online Links:

     > - <http://www.ngdc.noaa.gov/mgg/coastal/coastal.html>

     Type_of_Source_Media: CD-ROM
     Source_Contribution:
       Vol. 2 was used to create the onshore and offshore image of Grand Strand, South Carolina region for the project area

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

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?

   There are no attributes associated with a GeoTIFF image. Pixels (cells) convey only RGB values.

2. How accurate are the geographic locations?

3. How accurate are the heights or depths?

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

   NGDC compiled available bathymetry; spurious data were eliminated.

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

   Land elevations within the gridded dataset come from the United States Geological Survey/ National Image Mapping Agency (USGS/NIMA) 1:250,000 or 1 degree DEMs of the states. A description of the USGS/NIMA DEMs and how they were derived can be accessed on the World Wide Web at <http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem>. Our focus, however, is on the bathymetric soundings that are used in constructing the offshore regions of the grids.
   Soundings for each volume of the Coastal Relief model series are compiled from hydrographic surveys conducted by the National Ocean Service (NOS) and from various academic institutions. The surveys were carried out using a variety of sounding methods including SeaBeam 16-beam, 12-kHz swath mapping system (6000- >3000m operating water depths), General Instruments 17-beam, 36-kHz Hydrochart II swath mapping system (5-150m operating water depths), single-beam echosounder (e.g., 3.5 kHz narrow 2 degree beam), and lead-line sounding method. These latter surveys date as far back as the late 1800's.
   A wide range of navigation methods are also associated with the surveys. Visual navigation is based on three-point sextant fixes, theodolite intersections, and celestial fixes. Electronic navigation involves short to long range positioning systems that run the gamut from Loran-C (0.25 - 5 nm accuracy) to differential GPS (1 m accuracy).
   Despite the varying sounding and navigation techniques upon which they are based, all of the NOS soundings used in constructing the Coastal Relief Model meet rigorous standards for accuracy. The same standards are employed by the International Hydrographic Office and have remained relatively consistent since the 1800's. 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. The horizontal accuracy of the soundings is within a radius of 1.5 mm of the sounding location at the scale at which the soundings are recorded. NOS surveys are plotted at map scales that range from 1/10,000 for harbors and channels to 1/50,000 for open ocean surveys, with 1/20,000 being the most commonly used scale. 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. Differential GPS has improved this level of accuracy considerably for the most recent survey data.
   While the NOS soundings collected since 1965 have been recorded digitally, those collected prior to this time were recorded manually and then used to make hand-drawn bathymetric maps. Approximately 1,550 of these hand-drawn bathymetric maps have been digitized and assimilated into the NOS Hydrographic Database and, subsequently, were used in constructing the many volumes of the gridded dataset.

### 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 is freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of this dataset.

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

   Jane Denny
   U.S. Geological Survey
   Geologist
   384 Woods Hole Rd.
   Woods Hole, MA 02543-1543
   USA

   (508) 548-8700 x2311 (voice)
   (580)457-2310 (FAX)
   jdenny@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?

   > Although all data have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or 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 materials.
   > Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

4. How can I download or order the data?

   - Availability in digital form:

     Data format: | Image contains the onshore and offshore DEM of the project area off shore of Grand Strand, South Carolina in format TIFF (version unknown) GeoTIFF Size: 30 MB
     Network links: | <http://pubs.usgs.gov/of/2005/1346/ArcGIS/NGDC/ngdc_crm.zip>
     Media you can order: | DVD-ROM (Density 4.75 Gbytes) (format UDF)

   - Cost to order the data: none

5. What hardware or software do I need in order to use the data set?

   > This image is available as a GeoTIFF image with an accompanying world file. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GeoTIFF image.

### Who wrote the metadata?

Dates:
  Last modified: 23-Jan-2007
Metadata author:
  Jane Denny
  U.S. Geological Survey
  Geologist
  384 Woods Hole Rd.
  Woods Hole, MA 02543-1598
  USA

  (508) 548-8700 x2311 (voice)
  (508) 457-2310 (FAX)
  jdenny@usgs.gov

Metadata standard:
  FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:
  - <http://www.esri.com/metadata/esriprof80.html>

Generated by `mp` version 2.9.2 on Tue Mar 06 16:14:50 2007