Side-scan imagery of Apra Harbor, Guam U.S. Territory

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Frequently anticipated questions:


What does this data set describe?

Title: Side-scan imagery of Apra Harbor, Guam U.S. Territory
Abstract:
Gridded side-scan imagery collected in Apra Harbor, Guam U.S. Territory, USA. The GeoTIFF and Arc ASCII file includes data that were collected using a Klein 3000 high-resolution side-scan sonar system with dual operating frequencies of 100 and 500 kHz. The data were collected in 2008 by the NOAA Office of Coast Survey and the United States Navy Fleet Survey Team and were preliminarily processed by NOAA OCS using the Caris software. Additional processing and mosaicking was performed 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. 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) that can be accessed at: www.soest.hawaii.edu/pibhmc and is included in the ZIP file containing the side-scan GeoTIFF.
  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, Side-scan imagery of Apra Harbor, Guam U.S. Territory.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: 144.623
    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_ss_1m_445.jpg> (JPG)
    Side Scan/Acoustic Imagery

  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 5127 x 5727 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.

      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: mean lower low water
      Depth_Resolution: 0.01
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute Values

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    Backscatter data within a GSF file are arranged as small sequences of intensity values, one sequence per beam per ping. The intensity values represent the amplitude of echo returns to the sensor and can be related to seabed hardness and roughness.
    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?

    Benthic Habitat Mapping Group, Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), NOAA and the Joint Institute for Marine and Atmospheric Research (JIMAR) are the sources of this information.

  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?

The GeoTIFF and Arc ASCII of side-scan imagery 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 the supplemental information for instrument and survey information.


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: 22-Nov-2010 (process 1 of 1)
    The Klein 3000 system consists of a Klein towfish, a Transceiver/Processing Unit (TPU), and a computer for user interface. The along-track resolution is approximately 30cm at the 100m range scale, even when acquiring data at speeds up to 10 knots. Across-track resolution is typically 7.5cm at the 100m range scale. The achievable 0.3m resolution meets the OCS Hydrographic Surveys Specifications and Deliverables Manual for object detection. ISIS Sonar Pro is used to acquire data with the Klein 3000 SSS. Sonar Pro is a Windows-based acquisition software package that provides real-time data display and sonar control. Sonar Pro is used to acquire Klein 3000 data in XTF format. Data acquisition is monitored real time by a qualified sonar operator. The primary user settings that are adjustable during SSS acquisition are the range scale and the resolution. Typically, the range scale and resolution are set prior to logging data and not changed again until the surveyed depth area changes.

    Caris HIPS/SIPS (Hydrographic Information Processing System/ Side-scan Information Processing System) is used for processing, correcting, and analyzing all bathymetric, side scan, and phase-differencing bathymetric sonar data. Caris SIPS is used for converting and correcting side-scan sonar imagery and for contact selection and mosaic generation. After acquisition, SSS data are converted from XTF format to Caris HDCS format. Fish height, vessel heading (gyro), and vessel navigation records are then reviewed and corrected and recalculated. Data are then slant-range corrected to 0.1m with beam pattern correction. Side scan mosaics were created using the SIPS side scan editor. Mosaics consisted of combinations of lines that resulted in a seamless product after interpolation was applied during GeoBAR creation in Caris SIPS. Since the dataset is so large, a final mosaic was created using ArcGIS 9.x Raster Dataset Tools in the Toolbox. See the SWAMPFOX Data Acquisition and Processing Report included in the side-scan data download ZIP file (apra_ss_1m.zip) available from <http://www.soest.hawaii.edu/pibhmc>.

  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 Range resolution of sonar: see DAPR Raw sounding resolution: see DAPR Vertical accuracy of gridded product: see DAPR

  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 (Office of Ocean Exploration and the Pacific Islands Fisheries Science Center) and 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 Tue Sep 30 10:53:03 2014