Identification_Information:
  Citation:
    Citation_Information:
      Originator: National Oceanographic and Atmospheric Agency, Pacific Island Fisheries Science Center (PIFSC), 
        Coral Reef Ecosystem Division Benthic Habitat Mapping Group
      Publication_Date: 20091231
      Title: Backscatter imagery of Ni'ihau Island, Hawaii, USA
      Geospatial_Data_Presentation_Form: digital data
      Online_Linkage: http://www.soest.hawaii.edu/pibhmc
  Description:
    Abstract: Backscatter imagery extracted from gridded bathymetry of Ni'ihau Island, Hawaii, USA. 
      These data provide almost complete coverage between 0 and 100 meters. The backscatter dataset includes 
      Simrad EM3002d, Simrad EM300 and Reson 8101 data. The sonars frequencies are 300 kHz,30kHz and 240 kHz respectively and are 
      processed and gridded separately. Because of the similar sonar frequencies the data can be mosaicked nearly 
      seamlessly using GIS software. 
      This metadata is for the Simrad em300 backscatter data only.
    Purpose:
      The geotiffs of backscatter 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 supplemental information for description of 
      instrument and survey.
    Supplemental_Information:
      Data were collected aboard the NOAA Ship Hi’ialakai, a 218’ United States
      National Oceanographic and Atmospheric Agency research ship. The NOAA 
      Ship Hiialakai's survey sensors include a 30 kHz Simrad EM300 sonar 
      and a 300 kHz Simrad EM3002d sonar, which provide bathymetry and 
      backscatter data, a TSS/Applanix POS/MV Model 320, which measures position, 
      velocity, attitude and heading, and a Seabird SBE 9/11 plus CTD used to 
      measure sound velocity profiles. 
      Specific equipment configurations are documented in cruise metadata from 
      cruises HI0504.     
  Time_Period_of_Content:
    Time_Period_Information:
      Range of Dates/Times for HI0504:
        Beginning_Date: 20050613
        Ending_Date: 20050708
    Currentness_Reference: ground condition
  Status:
    Progress: Complete
    Maintenance_and_Update_Frequency: As needed
  Spatial_Domain:
    Bounding_Coordinates:
      West_Bounding_Coordinate: -160.293164
      East_Bounding_Coordinate: -159.902019
      North_Bounding_Coordinate: 22.071657
      South_Bounding_Coordinate: 21.719988
  Keywords:
    Theme:
      Theme_Keyword_Thesaurus: CoRIS Theme Thesaurus Version 1.0
      Theme_Keyword: EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Backscatter
      Theme_Keyword: Acoustic Imagery
      Theme_Keyword: Backscatter
    Place:
      Place_Keyword_Thesaurus: None
      Place_Keyword: Niihau
      Place_Keyword: Hawaii
      Place_Keyword: Main Hawaiian Islands
      Place_Keyword: United States of America
    Place: 
      Place_Keyword_Thesaurus: CoRIS Place Thesaurus Version 1.0
      Place_Keyword: OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Hawaiian Islands > Main Hawaiian Islands > Niihau 
      Place_Keyword: COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu 
  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 as the 
    sources of this information.
  Point_of_Contact: 
    Contact_Information: 
      Contact_Organization_Primary: 
        Contact_Organization: Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), 
          Pacific Islands Fisheries Science Center (PIFSC), NOAA National Marine Fisheries Service (NMFS)
      Contact_Address: 
        Address_Type: mailing and physical
        Address: 1680 East-West Road POST 833
        City: Honolulu
        State_or_Province: HI
        Postal_Code: 96822
        Country: USA
      Contact_Voice_Telephone: 808-956-5239
      Contact_Electronic_Mail_Address: pibhmc@soest.hawaii.edu
      Contact_Instructions: e-mail preferred
  Browse_Graphic:
    Browse_Graphic_File_Name: NII-bs_em300.jpg
    Browse_Graphic_File_Description: Backscatter
    Browse_Graphic_File_Description: Acoustic Imagery
    Browse_Graphic_File_Type: JPEG
  Data_Set_Credit: 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.
Data_Quality_Information:
  Attribute_Accuracy:
    Attribute_Accuracy_Report: 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.  
  Logical_Consistency_Report: These data are believed to be logically consistent 
      though no tests were performed
  Completeness_Report: Complete
  Positional_Accuracy:
    Horizontal_Positional_Accuracy:
      Horizontal_Positional_Accuracy_Report:
        Horizontal positioning system: GPS (SPS)
        Horizontal position accuracy: 25 meters
    Vertical_Positional_Accuracy:
      Vertical_Positional_Accuracy_Report: 1m
        Range resolution of sonar ~1.25 cm
        Raw sounding resolution: Variable
        Vertical accuracy of gridded product: 1% of water depth
  Lineage:
    Process_Step:
     Process_Description: 
      	Science Applications International Corporation’s (SAIC) ISS-2000 acquires, 
        processes and records data, provides survey control and underway quality 
        control displays. SAIC’s SABER processing software is used to process the 
        raw soundings, analyze the results, manually edit the sounding data to remove 
        outliers and derive average gridded data values. Additional data acquisition 
        and processing information can be found in the metadata for cruises HI0504.
       	Hawaii Mapping Research Group (HMRG) processing software was then used to
       	extract values of acoustic intensity from the soundings. HMRG is an organization
       	of scientists, engineers and technicians whose mission is to design, build, 		
        and operate tools for mapping the seafloor. HMRG is a group within the School 
        of Ocean and Earth Science and Technology at the University of Hawaii at Manoa. 
        The gsf2bs program (July, 2005) converts the swath bathymetry ping records contained 
        within a GSF (Generic Sensor Format) version 2.02 dataset into bs file format. This 
        is done as follows: (i) position each beam's bottom detect intensity sample at the 
        across-track location of that beam's bathymetry value; (ii) assuming a flat bottom 
        in the near neighborhood of the beam, compute across-track distances for all of the 
        beam's remaining intensity samples based on their temporal relation to the bottom 
        detect sample and the computed average sound velocity for that beam as derived from 
        its range and travel time; (iii) after all of the intensity samples from all beams 
        of a ping have been located in across-track distance, fill the gaps between them as
        necessary by interpolation. 
       	The conversion described above is necessary in order to run HMRG backscatter processing
       	operations on the data, such as filtering to remove noise, and to create netCDF grids, 
        raster images and GeoTIFF's. For more information on the backscatter processing technique 
        see <http://www.soest.hawaii.edu/pibhmc>. 
        The backscatter mosaic served here was created using the Mosaic to New Raster in the ArcMap 
        Version 9.3 Toolbox and exported from ArcGIS as a GeoTIFF file to create images containing 
        the em3002d backscatter data from the 2005 and 2006 surveys.
       	Software_Used:
       	SAIC ISS-2000 Acquisition Software, v 3.4 (20030610)
       	SAIC SABER Processing Software, v 2.0.2 (20030610)
       	Hawaii Mapping Research Group (HMRG) Processing Software	
       	GMT Generic Mapping Tools, v 4.4 (20090216)
        MB System, v 5.1.2beta05
        ESRI ArcMap 9.x
     Process_Date: 20091208
Spatial_Data_Organization_Information:
  Direct_Spatial_Reference_Method: Raster
  Raster_Object_Information:
    Raster_Object_Type: Grid Cell
    Row_Count: 7729
    Column_Count: 8027
    Vertical_Count: 1
Spatial_Reference_Information:
  Horizontal_Coordinate_System_Definition:
    Planar:
      Planar_Coordinate_Information:
        Planar_Coordinate_Encoding_Method: row and column
        Coordinate_Representation:
          Abscissa_Resolution: 1
          Ordinate_Resolution: 1
        Planar_Distance_Units: meters
      Grid_Coordinate_System:
        Grid_Coordinate_System_Name: Universal Transverse Mercator
        Universal_Transverse_Mercator:
          UTM_Zone_Number: 4
          Transverse_Mercator:
            Scale_Factor_at_Central_Meridian: 0.9996
            Longitude_of_Central_Meridian: -159
            Latitude_of_Projection_Origin: 0
            False_Easting: 500000
            False_Northing: 0
    Geodetic_Model:
      Horizontal_Datum_Name: D_WGS_1984
      Ellipsoid_Name: WGS_1984
      Semi-major_Axis: 6378137.000000
      Denominator_of_Flattening_Ratio: 298.257224
  Vertical_Coordinate_System_Definition:
    Depth_System_Definition:
      Depth_Datum_Name: mean lower low water
      Depth_Resolution:  0.01 meters
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
Entity_and_Attribute_Information:
  Overview_Description:
    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
Distribution_Information:
  Distributor:
    Contact_Information: 
      Contact_Organization_Primary: 
        Contact_Organization: Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), 
          Pacific Islands Fisheries Science Center (PIFSC), NOAA National Marine Fisheries Service (NMFS)
      Contact_Address: 
        Address_Type: mailing and physical
        Address: 1680 East-West Road POST 833
        City: Honolulu
        State_or_Province: HI
        Postal_Code: 96822
        Country: USA
      Contact_Voice_Telephone: 808-956-5239
      Contact_Electronic_Mail_Address: pibhmc@soest.hawaii.edu
      Contact_Instructions: e-mail preferred
  Resource_Description: Downloadable Data
  Distribution_Liability:
    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.
  Standard_Order_Process:
    Digital_Form:
      Digital_Transfer_Information:
        Format_Name: GeoTIFF, .tif
        Format_Information_Content: 
          TIFF is a format for storage, transfer, display, and printing of raster images. The TIFF file 
          structure allows both the ta and the image data to be encoded into the same file. GeoTIFF 
          refers to a TIFF file that has geographic data embedded as tags within the TIFF file. 
          The geographic data can be used to position the image in the correct location and geometry 
          on the screen of a geographic information display. Any GIS, CAD, Image Processing,
          Desktop Mapping and other types of systems using geographic images can read any GeoTiff file. 
          More specifically, files of this type can be added to ArcInfo and ArcView 8.x or higher and may 
          be viewed in the Table of Contents as a new raster layer. Image visualization software that does 
          not use geography as a basis for image placement can view a GeoTIFF image as if there were no 
          geographic information in the TIFF file. For example, GeoTIFF files can be viewed using Windows 
          Picture and Fax viewer.The GeoTIFF format is public domain, non-proprietary. 
        File_Decompression_Technique: none
        Transfer_Size: Variable
      Digital_Transfer_Option:
        Online_Option:
          Computer_Contact_Information:
            Network_Address:
              Network_Resource_Name: http://www.soest.hawaii.edu/pibhmc
    Fees: None
Metadata_Reference_Information:
  Metadata_Date: 20091208
  Metadata_Contact:
    Contact_Information: 
      Contact_Organization_Primary: 
        Contact_Organization: Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), 
          Pacific Islands Fisheries Science Center (PIFSC), NOAA National Marine Fisheries Service (NMFS)
      Contact_Address: 
        Address_Type: mailing and physical
        Address: 1680 East-West Road POST 833
        City: Honolulu
        State_or_Province: HI
        Postal_Code: 96822
        Country: USA
      Contact_Voice_Telephone: 808-956-5239
      Contact_Electronic_Mail_Address: pibhmc@soest.hawaii.edu
      Contact_Instructions: e-mail preferred
  Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
  Metadata_Standard_Version: FGDC-STD-001-1998
  Metadata_Time_Convention: local time
  Metadata_Access_Constraints: None
  Metadata_Use_Constraints: None
