ASV_SEISMICLINES- Seismic Survey Lines collected with Autonomous Surface Vehicle (ASV) IRIS in Apalachicola Bay and St. Geroge Sound, FL

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Frequently-anticipated questions:

What does this data set describe?

Title:
ASV_SEISMICLINES- Seismic Survey Lines collected with Autonomous Surface Vehicle (ASV) IRIS in Apalachicola Bay and St. Geroge Sound, FL
Abstract:
These data were collected under a cooperative mapping program between the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration Coastal Services Center (NOAA\CSC), and the Apalachicola National Estuarine Research Reserve (NERR). The primary objectives of this program were to collect marine geophysical data to develop a suite of seafloor maps to better define the extent of oyster habitats, the overall seafloor geology of the bay and provide updated information for management of this resource. In addition to their value for management of the bay's oyster resources, the maps also provide a geologic framework for scientific research and the public.
High-resolution bathymetry, backscatter intensity, and seismic profile data were collected over 230 square kilometers of the floor of the bay. The study focused on the Apalachicola Bay and western part of St. George Sound portions of the estuary in mostly in depths > 2.0 meters.
  1. How should this data set be cited?

    U.S. Geological Survey, 2007, ASV_SEISMICLINES- Seismic Survey Lines collected with Autonomous Surface Vehicle (ASV) IRIS in Apalachicola Bay and St. Geroge Sound, FL: Open-File Report 2006-1381, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Twichell, David C. , Andrews, Brian D. , Edmiston, H. Lee , and Stevenson, William R. , 2007, Geophysical Mapping of oyster habitats in a shallow estuary; Apalachicola Bay, Florida: Open-File Report 2006-1381, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -85.062698
    East_Bounding_Coordinate: -84.809586
    North_Bounding_Coordinate: 29.746495
    South_Bounding_Coordinate: 29.618458

  3. What does it look like?

    <http://pubs.usgs.gov/of/2006/1381/GIS/thumbnails/ASV_SeismicLines.jpg> (JPEG)
    JPEG image of seismic tracklines collected by ASV

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

    Beginning_Date: 03-Jun-2006
    Ending_Date: 27-Jun-2006
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • String (204)

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      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:
      Altitude_System_Definition:

  7. How does the data set describe geographic features?

    ASV_SeismicLines
    ASV seismic survey navigation lines for field activity 06001 (Source: USGS)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    FeatureID
    Not used (Source: ArcMarine)

    FeatureCod
    not used (Source: ESRI)

    LineName
    name of survey line (Source: USGS)

    JDay
    Julian Day (Source: USGS)

    ImageName
    Name of seismic profile associated with the survey line. (Source: USGS)

    SurveyID
    ID number used as join field with SurveyInfo Table for relationship class (Source: USGS)

    ValueDefinition
    2USGS Survey 06001

    VehicleID
    Id number identifying vehicle (survey platform) used to collect the data. Used as join field in relationship class to VehicleInfo table (Source: USGS)

    ValueDefinition
    2USGS Autonomous Surface Vehicle (ASV) IRIS

    DeviceID
    Identification number used to distinguish the type of acoustic sensor (Device) used to collect data. Also used as the join field for relationship class to MeasuringDeviceTable object (Source: USGS)

    ValueDefinition
    3EdgeTech FSSB-424

    SHAPE_Leng
    Length of survey line in meters

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?

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

    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov

Why was the data set created?

These data represent trackline navigation for seismic-reflection profiles collected from the Autonomous Surface Vehicle (ASV) IRIS during USGS field activity 06001 in Apalachicola Bay and St. George Sound, Florida. The purpose of these data is to manage the filenames and geographic locations of data that were actually collected.

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: 20-May-2007 (process 1 of 2)
    Seismic data were collected with an Edgetech FSSB 424 chirp subbottom profiling system. The seismic data, along with navigation, were acquired with JSTAR, a software package developed by Edgetech. The field data in .JSF format was converted to SEG-Y. Navigation was extracted from the raw SEG-Y format seismic data and converted to an ASCII text file. The ASCII navigation file was downsampled to a 30 second interval, and then imported to ArcGIS using the AddXYdata tool in ArcMap (v. 9.2). The points then were converted to a line using an ArcMap script Points_to_Line v2 developed at the USGS by VeeAnn Cross.

    Person who carried out this activity:

    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov

    Date: Jul-2007 (process 2 of 2)
    Exported feature class from personal geodatabase to a shapefile and projected to geographic.

    Person who carried out this activity:

    Brian Andrews
    U. S. Geological Survey
    Geographer
    384 Woods Hole Road
    Woods Hole, MA 02543-1598

    508-548-8700 x 2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov

  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?

    RTK GPS was used to navigate IRIS, the survey system used to collect the seismic reflection data. The GPS antenna was mounted directly over the seismic transducer.

  2. How accurate are the geographic locations?

    Navigation was recorded to all data acquisition systems using Real Time Kinematic GPS at a one second interval.
    Horizontal accuracy of the navigation is assumed to be +/- 1 meter. The shot point file and survey line file for the
    seismic data are both derived from the same navigation file that was logged by the seismic acquisition system, but
    because the two were processed differently, the shot points do not always fall directly on the survey line. To create
    the shot point file, the navigation was queried to extract every 500th point starting with shot point 500. By
    contrast, to create the survey line file, the navigation was queried at a one minute interval (every 60th point), and
    then a line was drawn using these points. Because of the different processing approaches, many of the shot points,
    although close, do not fall exactly on the survey line. If meter accuracy is truely needed, it would be best to
    extract the navigation from the archived SEG-Y seismic files.

  3. How accurate are the heights or depths?

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

    Navigation tracklines along which seismic data were not logged were deleted.

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

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 should not be used at resolutions for which they are not intended.
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.

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

    Brian Andrews
    U.S. Geological Survey
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.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?

    Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.
    Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    The data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS or ArcView 3.3 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.

Who wrote the metadata?

Dates:
Last modified: 30-Aug-2007
Metadata author:
U.S. Geological Survey
c/o Brian Andrews
Geographer
384 Woods Hole Rd.
Woods Hole, MA 02543-1598
USA

508-548-8700 x2348 (voice)
508-457-2310 (FAX)
bandrews@usgs.gov

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

Generated by mp version 2.9.2 on Thu Aug 30 14:18:37 2007