CRED Simrad em120 multibeam backscatter data from portions of the banktop and bank edge environments at Maro Reef, Hawaii, USA with 30 meter resolution in Arc ASCII format

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Frequently anticipated questions:


What does this data set describe?

Title:
CRED Simrad em120 multibeam backscatter data from portions of the banktop and bank edge environments at Maro Reef, Hawaii, USA with 30 meter resolution in Arc ASCII format
Abstract:
Multibeam backscatter imagery extracted from gridded bathymetry of Maro Reef, Northwestern Hawaiian Islands, USA. These data provide coverage between 20 and 5000 meters. The backscatter dataset includes data collected using Simrad EM300, Simrad EM3002d, Simrad EM120, and Reson 8101 multibeam sonars. The sonars frequencies are 30 kHz, 300 kHz, 12 kHz, and 240 kHz respectively and the backscatter data from each sonar are processed and gridded separately. These metadata are for the 30 m grid cell size Simrad em120 multibeam backscatter data only.
Supplemental_Information:
Multibeam data were collected aboard the R/V Kilo Moana, a 186' United States Navy owned research vessel operated by the University of Hawaii. The R/V Kilo Moana's survey sensors include a 12 kHz Simrad EM120 sonar and a 95 kHz Simrad EM1002 sonar, which provide bathymetry and imagery data, a TSS/Applanix POS/MV Model 320, which measures position, velocity, attitude and heading, and a Sippican MK-21/PC based XBT system plus a Seabird SBE 9/11 CTD both of which measured sound velocity profiles. Specific equipment configurations are documented in metadata from cruise: KM0206. These metadata can be accessed at: <http://www.soest.hawaii.edu/pibhmc/pibhmc_cruise-catalog.htm>.
  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), 200703, CRED Simrad em120 multibeam backscatter data from portions of the banktop and bank edge environments at Maro Reef, Hawaii, USA with 30 meter resolution in Arc ASCII format.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -171.372
    East_Bounding_Coordinate: -170.022
    North_Bounding_Coordinate: 25.754
    South_Bounding_Coordinate: 24.987

  3. What does it look like?

    <http://www.soest.hawaii.edu/pibhmc/NWHI_images/maro-bs_440.jpg> (JPEG)
    Multibeam Backscatter, Acoustic Imagery
    <http://www.soest.hawaii.edu/pibhmc/NWHI_images/maro-em120-bs_440.jpg> (JPEG)
    Multibeam Backscatter, Acoustic Imagery

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

    Beginning_Date: 22-Oct-2002
    Ending_Date: 16-Nov-2002
    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 2841 x 4519 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: 2
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -171
      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 30
      Ordinates (y-coordinates) are specified to the nearest 30
      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:
    Sidescan data within a Simrad 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 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?

    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?

This ASCII file of backscatter imagery was 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: 01-Nov-2002 (process 1 of 1)
    Multibeam data were collected using Simrad Neptune software. Multibeam data were processed using MB-System, an open source software package for the processing and display of bathymetry and backscatter imagery data. The data were destriped using mbfilter, a grazing angle correction was calculated and appplied to the data using mbbackangleold and mbanglecorrect, and the data were gridded using mbmosaic. ASCII files were created from netCDF grids using the Generic Mapping Tools (GMT). More information about MB-System and GMT can be found at: www.ldeo.columbia.edu/res/pi/MB-System/ www.soest.hawaii.edu/gmt/

  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 (SPS) Horizontal position accuracy: 25 meters

  3. How accurate are the heights or depths?

    1 m Range resolution of sonar ~1.25 cm Raw sounding resolution: Variable Vertical accuracy of gridded product: 1% of water depth

  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 and the Joint Institute for Marine and Atmospheric Research (JIMAR) University of Hawaii as the sources of this information. 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
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)


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