Mosaic of gridded multibeam and lidar bathymetry of the US Territory of Guam

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Frequently anticipated questions:


What does this data set describe?

Title:
Mosaic of gridded multibeam and lidar bathymetry of the US Territory of Guam
Abstract:
Gridded multibeam bathymetry is integrated with gridded lidar bathymetry. Gridded (5 m cell size) multibeam bathymetry were collected aboard NOAA Ship Hiialaka'i and R/V AHI and by the Naval Oceanographic Office and NOAA Office of Coast Survey in Apra Harbor. Lidar bathymetry were collected by the Naval Oceanographic Office and by the Joint Airborne Lidar Bathymetry Technical Center of Expertise. This dataset is for the shelf environment of the US Territory of Guam Island
Supplemental_Information:
Gridded multibeam data were collected by CRED in 2003 and 20007 aboard the Hi'ialakai, a 218' United States National Oceanographic and Atmospheric Administration (NOAA) research ship, and aboard the R/V AHI (Acoustic Habitat Investigator), a 25' survey launch owned and operated by the NOAA Pacific Islands Fisheries Science Center in Honolulu, HI. The metadata for these bathymetry is documented in the product metadata, guam_5m.txt on <ftp://ftp.soest.hawaii.edu/pibhmc/website/data/cnmi-guam/bathymetry> Multibeam data were also collected by the Naval Oceanographic Office and NOAA Office of Coast Survey in 2008, in Apra Harbor. These data are also presented in a 1-m resolution grid online, and metadata for these data are documented in the product metadata apra_bty_1m.txt on <http://www.soest.hawaii.edu/pibhmc/pibhmc_cnmi_apra_bathy.htm>. Lidar data were provided by the Naval Oceanographic Office, and were obtained using a SHOALS airborne system during January-March 2001. Additional lidar data were collected by the Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX). These data were collected using the CHARTS system between February 18 and May 20 2007. These data are available on NGDC and more detailed metadata for these data can be found on <http://www.csc.noaa.gov/digitalcoast/data/index.html>
  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), 20110304, Mosaic of gridded multibeam and lidar bathymetry of the US Territory of Guam.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: 144.608
    East_Bounding_Coordinate: 145.009
    North_Bounding_Coordinate: 13.727
    South_Bounding_Coordinate: 13.220

  3. What does it look like?

    <http://www.soest.hawaii.edu/pibhmc/CNMI_images/Guam_5m_bathymetry_mb&lidar_445.jpg> (JPG)
    Gridded Bathymetry

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

    Beginning_Date: 01-Mar-2001
    Ending_Date: 04-May-2008
    Currentness_Reference: ground condition

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

  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 11155 x 8574 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: 0.999600
      Longitude_of_Central_Meridian: 147.000000
      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 5.000000
      Ordinates (y-coordinates) are specified to the nearest 5.000000
      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?


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 PIFSC CRED, PIBHMC, NOAA OCS, NAVO, JALBTCX

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


Why was the data set created?

The data were derived in support of NOAA Coral Reef Conservation Program goals. Goal 1 is to map all U.S. Coral Reef Ecosystems. This data set specifically addresses Objective 1 and 4: to develop high-resolution benthic maps and to characterize priority deep water reefs and associated habitats. This integration of derived bathymetry with multibeam sonar data provides a GIS layer with expanded spatial coverage that may be used for benthic and essential fish habitat characterization, and for the study of geologic features. By combining the dataset with other bathymetry, backscatter, derivatives, and in situ data, they collectively compose benthic habitat maps designed to be used to understand and predict shallow depth (0m to 150m) benthic habitats for organisms that inhabit coral reef ecosystems.


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: 01-Mar-2011 (process 1 of 1)
    metadata apra_bty_1m.txt) on <ftp://ftp.soest.hawaii.edu/pibhmc/website/data/cnmi-guam/bathymetry> and <http://www.soest.hawaii.edu/pibhmc/pibhmc_cnmi_apra_bathy.htm> respectively. Lidar xyz data from the two sources (2001 data from Naval Oceanographic Office and 2007 data from the Joint Airborne Lidar Bathymetry Technical Center of Expertise) were gridded using nearneighbor, a Generic Mapping Tools (GMT) algorithm. GMT is an open source collection of tools for manipulating geographic data sets. Additional information about GMT can be found at: <http://www.soest.hawaii.edu/gmt> and additional information about the multibeam data processing is recorded in the cruise metadata. This results in a netCDF grid file format, which is then converted to an ArcGIS ASCII file format using LINUX/UNIX commands in combination with GMT. ArcGIS ASCII files can then be converted into raster format using ArcToolbox (Conversion Tools > To Raster > ASCII to Raster). For both lidar data sets, positive values (i.e. those on land), were removed, leaving only depth values. The four bathymetry grids were combined in ESRI ArcMap using the Mosaic Tool (ArcToolbox > Data Management Tools > Raster > Raster Dataset > Mosaic). The Mosaic Method used was "First" which allows the user to prioritize which values are used for overlapping pixels. The four bathymetry data sets were prioritized in the following order, based on the perceived accuracy of the four data sets: Apra Harbor multibeam, CRED multibeam, JALBTCX lidar, NAVO lidar. This resulted in the final combined bathymetry grid (gua_mb_ld.asc).

  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: GPS C/A Horizontal position accuracy: 25 meters

  3. How accurate are the heights or depths?

    Range resolution of sonar: varies with depth Raw sounding resolution: varies with depth Vertical accuracy of gridded sonar product: ~ 1% of water depth Vertical accuracy of derived bathymetry product: 5 meter range

  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 (PIFSC) Coral Reef Ecosystem Division (CRED), the Joint Institute for Marine and Atmospheric Research (JIMAR) University of Hawaii, the NOAA Office of Coast Survey (NOAA OCS), the Naval Oceanographic Office (NAVO), and the Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX).

  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: 06-Sep-2011
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 24 10:39:26 2014