Gridded multibeam bathymetry of Apra Harbor, Guam U.S. Territory

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Frequently anticipated questions:


What does this data set describe?

Title:
Gridded multibeam bathymetry of Apra Harbor, Guam U.S. Territory
Abstract:
Gridded bathymetry from Apra Harbor, Guam U.S. Territory. The netCDF and Arc ASCII grids include multibeam bathymetry from the Reson SeaBat 8125 multibeam sonar collected in 2008 by the NOAA Office of Coast Survey and the United States Navy Fleet Survey Team. The sonar frequency is 455 kHz and the data are gridded at 1 m resolution. The data served here were extracted from a Caris project provided by OCS and converted to netCDF and Arc ASCII grids by the NOAA Coral Reef Ecosystem Division.
Supplemental_Information:
Survey data were acquired by the United States Navy (USN) Fleet Survey Team (FST) with Survey Vessel Swamp Fox. A Reson 8125 multibeam echosounder was mounted from an arm on the port side of the vessel. The Klein 3000 Side Scan Sonar is operated in the stern-towed configuration. Additional detailed information on data acquisition, equipment configuration, and corrections can be found in the Data Acquisition and Processing Report (DAPR), SWAMPFOX_DAPR_2008.pdf, that can be accessed at: www.soest.hawaii.edu/pibhmc and is included in the ZIP file containing the bathymetry grids.

Vertical_Coordinate_System_Definition Depth_System_Definition

  1. How should this data set be cited?

    Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), 20100901, Gridded multibeam bathymetry of Apra Harbor, Guam U.S. Territory.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: 144.614
    East_Bounding_Coordinate: 144.676
    North_Bounding_Coordinate: 13.464
    South_Bounding_Coordinate: 13.418

  3. What does it look like?

    <http://www.soest.hawaii.edu/pibhmc/CNMI_images/apra_bty_1m_445.jpg> (JPEG)
    Multibeam Bathymetry

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

    Beginning_Date: 29-Mar-2008
    Ending_Date: 04-May-2008
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: 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 5061 x 6664 x 1, type Grid Cell

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 55
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: 147
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0

      Planar coordinates are encoded using Row and Column
      Abscissae (x-coordinates) are specified to the nearest 1
      Ordinates (y-coordinates) are specified to the nearest 1
      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:
    Depth values are real values based on the average of the soundings that fell within the extracted grid cells. The number of soundings per grid cell range from >1000 soundings in shallow depths to as few as 20 soundings in deeper areas. A total error budget for these data have not been developed. Therefore, the accuracy of depth measurements is reported in the DAPR.
    Entity_and_Attribute_Detail_Citation: none


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?

    NOAA OCS, USN FST, PIBHMC, CRED, PIFSC, NOAA, and JIMAR

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

    Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)
    NOAA IRC
    Honolulu, HI 96818

    808 725-5360 (voice)
    808 725-5429 (FAX)
    nmfs.pic.credinfo@noaa.gov

    Contact_Instructions: e-mail preferred


Why was the data set created?

These data were collected in response to a request by the USN for a cooperative modern hydrographic survey with NOAA to provide contemporary hydrographic data to update the nautical charts in the area. The USN plans to use Apra Harbor, Guam as a primary port-of-call. These data will support safe navigation for the USN fleet in Apra Harbor by providing IHO Order 1 hydrography. They will also aid in ongoing habitat mapping efforts by NOAA PIFSC CRED.

These netCDF and ASCII grids were created using data gathered from multibeam soundings for use as a planning and reference document. The data are also being used for benthic habitat mapping, for locating Essential Fish Habitat, and for studying geologic features of the area. Refer to supplemental information for description of instrument and survey.


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: 15-Nov-2010 (process 1 of 1)
    Refer to the the Data Acquisition and Processing Report (DAPR) that can be accessed at: www.soest.hawaii.edu/pibhmc and is included in the ZIP file containing the bathymetry grids for detailed information on the bathymetry data processing steps.

  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?

    Data are collected for resource management and research purposes and are tested for internal consistency; however, no effort is made to compare these data to external references or to other published data.

  2. How accurate are the geographic locations?

    Horizontal positioning system: see DAPR Horizontal position accuracy: see DAPR

  3. How accurate are the heights or depths?

    see DAPR Raw sounding resolution: Variable

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

    Complete

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

    These data are believed to be logically consistent though no tests were performed


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:
These data are not to be used for navigation purposes. Please acknowledge NOAA Pacific Islands Fisheries Science Center, the Joint Institute for Marine and Atmospheric Research (JIMAR) University of Hawaii, the NOAA Office of Coast Survey, and the USN Fleet Survey Team as the sources of this information.

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

    Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)
    NOAA IRC
    Honolulu, HI 96818

    808 725-5360 (voice)
    808 725-5429 (FAX)
    nmfs.pic.credinfo@noaa.gov

    Contact_Instructions: e-mail preferred
  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    These data are not to be used for navigational purposes. NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 12-Mar-2014
Last Reviewed: 02-Dec-2010
Metadata author:
Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)
NOAA IRC
Honolulu, HI 96818

808 725-5360 (voice)
808 725-5429 (FAX)
nmfs.pic.credinfo@noaa.gov

Contact_Instructions: e-mail preferred
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)


Generated by mp version 2.9.13 on Thu Apr 17 10:38:42 2014