APBAY2M_BATH.tif- 2m GeoTIFF of Swath Bathymetry of Apalachicola Bay, Florida

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Frequently-anticipated questions:

What does this data set describe?

Title:
APBAY2M_BATH.tif- 2m GeoTIFF of Swath Bathymetry of Apalachicola Bay, Florida
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, APBAY2M_BATH.tif- 2m GeoTIFF of Swath Bathymetry of 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:

    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: -85.100148
    East_Bounding_Coordinate: -84.870076
    North_Bounding_Coordinate: 29.735565
    South_Bounding_Coordinate: 29.587799

  3. What does it look like?

    <http://pubs.usgs.gov/of/2006/1381/GIS/thumbnails/ApBay2m_Bathtiff.jpg> (JPEG)
    color coded image

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

    Beginning_Date: 05-Apr-2005,20060602
    Ending_Date: 05-Apr-2005,20060603
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: remote-sensing image

  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 8000 x 11000 x 1, type Pixel

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -87.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 2.000000
      Ordinates (y-coordinates) are specified to the nearest 2.000000
      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_Distance_Units: meters
      Depth_Encoding_Method: Attribute values

  7. How does the data set describe geographic features?

    Band_1

    ObjectID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Value

    Count

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 image represents high-resolution bathymetric soundings of the bottom of Apalachicola Bay, Florida. This image covers approximately 145 square kilometers of portions of Apalachicola Bay between 0m -16.0m deep.

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: Dec-2006 (process 1 of 5)
    Bathymetric data were corrected for variations in the speed of sound throughout the water column; sound velocity profiles were acquired throughout the survey area using an Applied MicroSystems SVPlus Sound Velocimeter. These data were downloaded and reformatted to the required format needed for use within University of New Brunswick's Ocean Mapping Group (OMG) SwathEd multibeam processing software. The raw Submetrix 2000 Series data were "unraveled" and reformatted into the OMG format. This process creates several files on disk:
    1) bathymetric soundings 2) raw sidescan backscatter 3) navigation 4) parameter files describing the configuration of the system (i.e. offsets between motion reference unit and GPS antenna, etc). This process also incorporates the sound velocity profiles in order to properly trace the rays given the structure of the water column.

    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: Dec-2006 (process 2 of 5)
    The OMG formatted bathymetric data were then graphically edited using the SwathEd multibeam processing software. This enabled editing on a "ping-by-ping" basis, both in the across- and along-track dimension. Spurious or erroneous data were removed. The navigation data were also graphically examined for each line of data.

    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: Dec-2006 (process 3 of 5)
    Soundings were corrected to mean lower low water (MLLW) using high-resolution Real-Time Kinematic Global Positioning System (RTKGPS) measurements. The one second RTK data were smoothed in MatLab using a 3rd order polynomial and then merged with each line file in SwathEd.

    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: Dec-2006 (process 4 of 5)
    Soundings data were gridded using the weigh_grid routines from SwathEd. Soundings were corrected to mean lower low water during the weigh_grid operation using the real time kinematic Differential Global Positioning navigation files.
    The final weigh_grid parameters used were: weigh_grid -omg -coeffs -butter -lambda 5 -cutoff 20
    Max_incidence angle was not used on most lines as it allowed using sounding from the entire swath. Only lines from rough days when the vessel heave was large were gridded with a small incidence angle to maximize the good data from adjacent lanes and reduce the noisy data.

    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

    (process 5 of 5)
    Final SwathEd *r4 grid was imported to IVS Dmagic and converted to a *dtm and *.geo file. A suitable color ramp and hillshade parameters were applied creating a *shade file. IVS shade file (.shade) was then converted to an 8 Bit unsigned integer GeoTIFF using IVS ImageViewer.

    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?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

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

    This GeoTIFF image is an image representation of the raster grid (apbay2mbath) for the Apalachicola Bay portion of the study area. Bathymetric tie lines were collected and used for qualitative assessment but were not included in the final grids or GeoTIFF.

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

    These data have not been quantitatively compared to previous hydrographic data, although they generally agree with qualitative comparison of published NOAA charts

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:
Data are not intended for navigational use.
These data should not be used at resolutions for which it is 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 dataset 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?

    These data are available in GeoTIFF format. The user must have software capable of viewing a GeoTIFF data file.

Who wrote the metadata?

Dates:
Last modified: 27-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 Mon Aug 27 15:27:55 2007