Metadata for Eastern Samoa Multibeam Compilation Grid - esvp200m

Frequently-anticipated questions:

What does this data set describe?

Title: esvp200m
This dataset is a compilation of all available deep-water multibeam and single-beam sonar bathymetry in the Eastern Samoa Volcanic Province (ESVP) as of November 20, 2007. Bathymetric datasets were compiled and gridded using the software package MB-System. Cell resolution is 200 meters. Regional bathymetry was compiled for the purpose of interpreting the marine geomorphology of the ESVP, and identifying and characterizing previously undocumented seamounts. This dataset was created by Jed Roberts as the foundation for his thesis entitled The Marine Geomorphology of American Samoa: Shapes and Distributions of Deep Sea Volcanics available from Oregon State University.
  1. How should this data set be cited?

    Roberts, J., 2007. The Marine Geomorphology of American Samoa: Shapes and Distributions of Deep Sea Volcanics, M.S. thesis, Oregon State University, Corvallis, OR, 92 pp., <>
    Wright, D.J., Roberts, J., Fenner, D., Smith, J.R., Koppers, A.A.P., Naar, D., Hirsch, E.R., Clift, L.W., and Hogrefe, K.R., Seamounts, ridges, and reef habitats of American Samoa, in Harris, P.T. and Baker, E.K. (eds.), Seafloor Geomorphology as Benthic Habitat: GeoHab Atlas of Seafloor Geomorphic Features and Benthic Habitats, Elsevier, Amsterdam, 791-806, 2012.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -171.001
    East_Bounding_Coordinate: -167.499
    North_Bounding_Coordinate: -13.175
    South_Bounding_Coordinate: -15.536

  3. What does it look like? See study area map at <>

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

    Beginning_Date: 1984
    Ending_Date: 2007

  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 1273 x 1888 x 1, type Grid Cell
        Depths expressed in decimal degrees

    2. What coordinate system is used to represent geographic features?

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 0.001855
      Ordinates (y-coordinates) are specified to the nearest 0.001855

      The horizontal datum used is North American Datum of 1927.
      Spheroid is Clarke 1866, 6378206.400000, 294.978698, Mean sea level.
      Horizontal units are decimal degrees, Zunits are meters, "projection" is "geographic".

  7. How does the data set describe geographic features?


    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    GMT (Generic Mapping Tools) grdinfo:
    grdfile format: cf (# 10)
    x_min: 189 x_max: 192.5 x_inc: 0.00185381 name: user_x_unit nx: 1888
    y_min: -15.5 y_max: -13.2 y_inc: 0.00180676 name: user_y_unit ny: 1273
    z_min: -7156.98 z_max: -5.0029 name: user_z_unit
    scale_factor: 1 add_offset: 0

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?

    Main contributors were Dawn Wright, Oregon State University; Anthony Koppers, Oregon State University (Scripps Seamount Catalog); Dave Naar, University of South Florida; Joyce Miller and Scott Ferguson, NOAA Coral Reef Ecosystem Division/Pacific Islands Benthic Habitat Mapping Center/Pacific Fisheries Science Center. There were several additional contributors that are acknowledged in the file "multibeam.xls," which also includes a complete list of the bathymetric datasets used to create this regional dataset, as well as information about the sonar data collection systems. This information can also be found in Jed Roberts' thesis.

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

    Dawn Wright
    Davey Jones' Locker Seafloor Mapping Lab and Marine GIS Lab
    Department of Geosciences
    104 Wilkinson Hall
    Oregon State University
    Corvallis, Oregon 97331-5506
    541-737-1200 (FAX)

Why was the data set created?

This is a compilation of deepwater (> 250-500 m) multibeam bathymetry in American Samoa, compiled for the purpose of geomorphological analyses as pertaining to seamounts and volcanic lineaments, as well as for regional cartography.

How was the data set created?

  1. From what previous works were the data drawn?
    Grid compiled at 200m resolution from raw multibeam bathymetry with varying horizontal and vertical accuracy. See metadata for cruises MRTN05WT, PPTU03WT, PPTU04WT, RNDB15WT, RNDB16WT, BMRG08MV, BMRG09MV, KIWI05RR, AVON02MV, AVON03MV, COOK15MV, DRFT09RR, DRFT10RR, DRFT11RR, KM0506, KOK0510, and KOK0511 available at SIOExplorer.

  2. How were the data generated, processed, or modified?
    The mbgrid command in MB-System was used to compile raw multibeam files into a single GMT grid. The GMT grid was then imported to Fledermaus and exported as an Arc ASCII grid. Final data preparation was performed on machine running Microsoft Windows 2000 Version 5.2 (Build 3790), Service Pack 2; ESRI ArcGIS
    MB-System Example
    mbgrid -Idatalist.txt -E180/180/m -R189/192.5/-15.5/-13.2 -Oblahblah -L1 -C1 -X0
    .1 -A1 -N -V
    grdinfo blahblah.grd
    grd2xyz blahblah.grd
    I: Data list filename.
    E: Spatial resolution.
    R: Regional bounds.
    O: Output file name (".grd" automatically appended).
    L: "1" if longitude range is from 0 to 360 (common with SIO data).
    C: Number of grid cells splined to edge of grid (for smoothing).
    X: Extends the grid for spline interpolation.
    A: "1" if depth values are positive.  "2" if depth values are negative.
    N: Gives empty grid cells a value of "NaN" rather than 99999.9.
    V: Shows printout on screen of the mbgrid command executing.
    MIRONE color scheme: ML -- hsv
    Min Z: 5.0029
    Max Z: 7156.98
    Hillshade: 135 degrees
    Image width: 3488 pixels
    Data covered by newer swaths.
    PIBSC data not included.

  3. What similar or related data should the user be aware of? See American Samoa data archive at <> or Scripps Seamount Catalog at <>, or SIOExplorer at <>.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?Depth soundings were "cleaned" with a 2nd standard deviation filter to flag outliers (i.e., data that exceeded the second standard deviation of surrounding data and those that exceeded two percent of the noise limit were flagged as not valid or removed).

  2. How accurate are the geographic locations? Horizontal navigational accuracy of various cruises on which data were collected is ~25-100 m. Horizontal error is not expected to exceed the 200 meter cell size.

  3. How accurate are the heights or depths? Varies by multibeam or single-beam sonar system. The deepest and furthest off-nadir locations experience the greatest loss of accuracy. Varies by multibeam or single-beam sonar system. Most recent multibeam surveys (e.g. post-2000) claim vertical accuracy of 15 meters or ~1-5% of water depth.

  4. Where are the gaps in the data? What is missing? See coverage map at <>

  5. How consistent are the relationships among the observations, including topology? All internally, logically consistent. Arc-node topology not applicable for this raster grid.

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: Not for navigational purposes. Please cite authors when using the data for your own work in print or on the web.

  1. Who distributes the data set? Davey Jones' Locker Lab, Oregon State University, <>

  2. What's the catalog number I need to order this data set?

    None required.

  3. What legal disclaimers am I supposed to read? None

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 14-Dec-2012
Metadata authors:
Davey Jones' Locker Lab, Oregon State University.
c/o Jed Roberts, Dawn Wright.
104 Wilkinson Hall, Oregon State University, Corvallis, OR. 97331-5506.

541-737-8818 (voice)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Initially generated by mp version 2.8.6 on Thu Jan 31 16:51:11 2008