CRED Gridded bathymetry of the south central coast of Tutuila from Fagatele Point to the eastern end of the airport, American Samoa

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Frequently-anticipated questions:

What does this data set describe?

Title:
CRED Gridded bathymetry of the south central coast of Tutuila from Fagatele Point to the eastern end of the airport, American Samoa
Abstract:
Gridded bathymetry of the south central coast of Tutuila from Fagatele Point to the eastern end of the airport, American Samoa between 20 and 250 meters. This survey includes portions of Fagalete Bay National Marine Sanctuary. Almost complete bottom coverage was achieved in this survey.
Supplemental_Information:
Data were collected aboard the R/V AHI (Acoustic Habitat Investigator), a 25ó survey launch owned and operated by the NOAA Pacific Islands Fisheries Science Center in Honolulu, HI. The R/V AHIós survey sensors include a 240 kHz RESON 8101-ER sonar providing bathymetry and imagery data, a TSS/Applanix POS/MV Model 320 which measures position, velocity, attitude and heading, and a Seabird SBE 19 CTD used to measure sound velocity profiles.

Equipment serial numbers and software versions are as follows:

RESON 8101-ER multibeam echosounder DOC inventory #: CD0000537418 Firmware, dry: 8101-2.07-2D4D Firmware, wet: 8101-1.06-2F6B

POS/MV Model 320, version 3 DOC inventory #: CD0000476647 PCS serial #: 474 IMU serial #: 203 Controller software: v 1.0.5.0

Seabird SBE19 CTD: Serial #: 3029

R/V AHI Lever Arm Distances and Alignment Offsets The R/V AHI Reference Point (RP) is defined to be the intersection of the vessel's centerline, the cabin deck and the bulkhead immediately aft of the transducer. This is marked by a punch in the deck weld at that location. Positive X means the point is forward of the RP, positive Y means the point is to starboard of the RP, positive Z means the point is below the RP. The loaded waterline is defined as the intersection of the vesselós performance wing with the hull at the transom.

Antenna Baseline Distance, m: 1.229 Transducer depth below waterline, m 0.62

RP to IMU 0.80 0.00 0.08 RP to Primary GPS Antenna -3.55 -0.61 -1.88 RP to Vessel 0.16 0.00 0.77 RP to Sensor 1(MB transducer) 0.16 0.00 0.77 RP to Sensor 2 0 0 0 RP to Aux. GPS Antenna 0 0 0 RP to Heave lever arm(deg) -0.67 0.00 0.00 IMU rotation Ref. Frame, deg 0 0 0 Sensor 1 rotation Ref. Frame, deg 0 0 0 Sensor 2 rotation Ref. Frame, deg 0 0 0

Roll offset: +0.5 deg Pitch offset: 0.0 deg Gyro offset: 0.0 deg

  1. How should this data set be cited?

    Benthic Habitat Mapping Group, CRED, PIFSC, NOAA, 20040314, CRED Gridded bathymetry of the south central coast of Tutuila from Fagatele Point to the eastern end of the airport, American Samoa.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -170.781202
    East_Bounding_Coordinate: -170.691269
    North_Bounding_Coordinate: -14.330055
    South_Bounding_Coordinate: -14.384133

  3. What does it look like?

    <http://www.pifsc.noaa.gov/cred/hmapping/img/original/06j-tutuila_sc-10.jpg> (JPEG)
    Gridded bathymetry

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

    Beginning_Date: 17-Feb-2004
    Ending_Date: 12-Mar-2004
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: raster 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 597 x 969 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: 10000000

      Planar coordinates are encoded using Row and Column
      Abscissae (x-coordinates) are specified to the nearest 10
      Ordinates (y-coordinates) are specified to the nearest 10
      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:
    Depth values are real values based on the average of the soundings that fell within the extracted grid cells. 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 this survey has not been developed, therefore the accuracy of depth measurements should be considered to be within 1 meter.
    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

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

    Benthic Habitat Mapping Group,
    c/o Joyce Miller
    1125B Ala Moana Blvd
    Honolulu, HI 96814
    USA

    808-592-8303 (voice)
    joyce.miller@noaa.gov

Why was the data set created?

This grid was created using data gathered from multibeam soundings for use as a planning and reference document. 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: 14-Mar-2004 (process 1 of 1)
    Science Applications International Corporation&oacute;s (SAIC) ISS-2000 acquires, processes and records data, provides survey control and underway quality control displays. SAIC&oacute;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. GMT was then used to reformat the grid into final form. Interactive Visualization System&oacute;s Fledermaus and ESRI ArcGIS were used for viewing results and creating browse objects.

    The data have been corrected for predicted tides based on the NOAA NOS tide station in Pago Pago harbor

    Software used: SAIC ISS-2000 Acquisition Software, v 3.4.4 (20040114) SAIC SABER Processing Software, v 3.0 (20031218) GMT Generic Mapping Tools, v 3.4.2 (20021002)

  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: 5

  3. How accurate are the heights or depths?

    Range resolution of sonar ~ 1.25 cm Raw sounding resolution: 1 cm Vertical accuracy of gridded product ~ 1 meter

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

    Complete

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

    Unspecified

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 the NOAA Coral Reef Ecosystem Division, Pacific Islands Fisheries Science Center as the source of this information.

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

    Benthic Habitat Mapping Group, CRED, PIFSC, NOAA
    c/o Joyce E. Miller
    Oceanographer
    1125 'B' Ala Moana Blvd
    Honolulu, Hawaii 96814
    USA

    808-592-8303 (voice)
    joyce.miller@noaa.gov

  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-Aug-2008
Metadata author:
Benthic Habitat Mapping Group, CRED, PIFSC, NOAA
c/o Dr. Michael Parke
Research Biologist
1125 'B' Ala Moana Blvd
Honolulu, Hawaii 96814
USA

808-592-7025 (voice)
michael.parke@noaa.gov

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.8.23 on Fri Sep 5 04:18:56 2008