ASV_SEISMICSHOT500 - Shot Points at 500 Shot Intervals for Seismic Data Collected with Autonomous Surface Vehicle (ASV) IRIS in Apalachicola Bay and St. George Sound, FL.

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Frequently-anticipated questions:

What does this data set describe?

Title:
ASV_SEISMICSHOT500 - Shot Points at 500 Shot Intervals for Seismic Data Collected with Autonomous Surface Vehicle (ASV) IRIS in Apalachicola Bay and St. George 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 St. George Sound portions of the estuary mostly in depths > 2.0 meters.
  1. How should this data set be cited?

    U.S. Geological Survey, 2007, ASV_SEISMICSHOT500 - Shot Points at 500 Shot Intervals for Seismic Data Collected with Autonomous Surface Vehicle (ASV) IRIS in Apalachicola Bay and St. George 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: -85.062548
    East_Bounding_Coordinate: -84.809732
    North_Bounding_Coordinate: 29.746337
    South_Bounding_Coordinate: 29.618655

  3. What does it look like?

    <http://pubs.usgs.gov/of/2006/1381/GIS/thumbnails/ASV_SeismicShot500.jpg> (JPEG)
    JPEG image of seismic shots on ASV lines.

  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):

      • Entity point (4183)

    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_SeismicShot500
    Shotpoint navigation for ASV seismic data collected during 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.

    Lon
    Longitude coordinate of shot (Source: USGS)

    Lat
    Latitude coordinate of shot (Source: USGS)

    Line
    Name of survey line and file name (Source: USGS)

    Shot
    The number of the seismic shot in 500 shot intervals (Source: USGS)

    UTMX
    The X coordinate in Universal Transverse Mercator (UTM), meters (Source: USGS)

    UTMY
    The Y Coordinate in Universal Transverse Mercator (UTM), meters (Source: USGS)

    YEAR_
    Calendar year data were collected (Source: USGS)

    JDHrMinSec
    Time in Julian day, hour, minute, second format. (Source: USGS)

    JDay
    Day of the year indentified as Julian day. (Source: USGS)

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?

This shapefile represents the shotpoints at a 500 shot interval derived from the navigation for seismic-reflection profiles collected from the ASV IRIS during USGS field activity 06001 in Apalachicola Bay and St. George Sound, Florida. The purpose of these data is to provide geographic locations of shot points so that features in the seismic profiles can be properly located along the tracklines.

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)
    Navigation was extracted from raw SEG-Y format and converted to ASCII text file. The file containing navigation for each shot was then queried to extract shots at 500 shot interval using the awk script makenav developed for USGS by Bill Danforth. The 500 shot file for each survey line was concatenated and imported to ArcGIS 9.1 then converted to a point feature class.

    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 the survey systems for seismic-reflection systems. The GPS antenna was mounted over the seismic system.

  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?

    Shot points are not available for sections of the survey lines where seismic data were not logged.

  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 14:18:40 2007