Single-Beam derived bathymetric contours of Lake Okeechobee, Florida (2001) in Esri shapefile format

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Frequently anticipated questions:

What does this data set describe?

Title:
Single-Beam derived bathymetric contours of Lake Okeechobee, Florida (2001) in Esri shapefile format
Abstract:
Lake Okeechobee is located in south Florida and is bounded by the Kissimmee River Basin to the north and Everglades National Park to the south. Lake Okeechobee is the largest lake (1,890 square kilometers [km2]) in Florida and encompasses a drainage area of over 14,200 km2. The lake provides agricultural water supply, back-up water supply for urban areas, flood protection to adjacent communities, critical bird and fisheries habitats, is part of the Okeechobee Waterway navigation canal, and offers boating-related recreation. Over the past 100 years, land use change and population increases have adversely impacted the health of the lake, mostly by extreme water level fluctuations and excessive nutrient loading mainly from agricultural activities.
High-resolution bathymetric mapping was conducted in 2001 in Lake Okeechobee by the USGS, in cooperation with the South Florida Water Management District (SFWMD). High-resolution, acoustic bathymetric surveying is a proven method to map sea and lake floor elevations. Survey tracklines were spaced 1000 meters apart and orientated in a north-south direction. Tracklines collected in an east-west orientation (intersecting tracklines) functioned to serve as a cross-check and to assess the relative vertical accuracy of the survey. Ideally, vertical data values at the crossing should be exactly the same. In reality, this is not always the case due to random errors associated with the survey system.
Several perimeter survey lines were also collected. Soundings were collected along each trackline at 3-meter spacing. Approximately 1,550 kilometers of survey lines were collected. In shallow areas, data were collected in a minimum of 0.6 meters water depth, unless potential damage to the bottom environment or the boat/motors was a significant possibility.
This report serves as an archive of processed single-beam bathymetry data that were collected in Lake Okeechobee, Florida, in 2001. Geographic information System (GIS) data products include XYZ data, bathymetric contours, and USGS quadrangle maps and associated formal Federal Geographic Data Committee (FGDC) metadata.
  1. How might this data set be cited?
    Hansen, Mark, 2015, Single-Beam derived bathymetric contours of Lake Okeechobee, Florida (2001) in Esri shapefile format: Archive of Bathymetry Data Collected in South Florida from 1995 to 2015 U.S. Geological Survey Data Series-1031, U.S. Geological Survey, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -81.018336
    East_Bounding_Coordinate: -80.611538
    North_Bounding_Coordinate: 27.209675
    South_Bounding_Coordinate: 26.717325
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2001
    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):
      • Ring composed of arcs (170)
    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 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in decimal degrees. The horizontal datum used is D North American 1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: NAVD88
      Depth_Resolution: 0.01
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    DS1031-LOkee_WGS84_NAVD88-G99_SB.contours.shp
    Post-processed, bathymetric contours of Lake Okeechobee, Florida. (Source: USGS)
    FID
    Internal feature number (Source: Esri) Sequential unique whole numbers that are automatically generated
    Shape
    Feature geometry (Source: Esri) Polyline
    Length
    Length of feature (Source: Esri)
    Range of values
    Minimum:555.645153
    Maximum:10145.363926
    Units:meters
    Resolution:0.001
    Contour
    NAVD88 elevation contour (Source: USGS)
    Range of values
    Minimum:0
    Maximum:3.5
    Units:meters
    Resolution:1

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Mark Hansen
  2. Who also contributed to the data set?
    South Florida Water Management District provided funding for the study. Mark Hansen was the USGS principal investigator. Nancy T. DeWitt performed a significant portion of bathymetric survey data collection and processing. BJ Reynolds and Phil Thompson provided data collection support.
  3. To whom should users address questions about the data?
    Mark Hansen
    U.S. Geological Survey
    Oceanographer
    600 Fourth Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    mhansen@usgs.gov

Why was the data set created?

Of primary interest to the USGS and SFWMD is the quantification of the present day lakebed in Lake Okeechobee. This information can be used by water management decision-makers to better assess the water capacity of the lake at various levels.

How was the data set created?

  1. From what previous works were the data drawn?
    USGS Lake Okeechobee bathymetry (source 1 of 1)
    Hansen, Mark DeWitt, Nancy T., 2002, High Resolution Bathymetric Mapping.

    Type_of_Source_Media: web report
    Source_Contribution: Original processed bathymetric data.
  2. How were the data generated, processed, and modified?
    Date: 2001 (process 1 of 2)
    The final edited and reviewed processed sounding data were entered into a gridding and contouring software package, CPS-3, which was created by Radian corporation. Contours were generated using an inverse distance weighting and grid step-down operation. Contour vectors were output then entered into Adobe Illustrator (Adobe) to utilize a plug-in tool called, Map Publisher. Contours were then overlaid on USGS rectified aerial photograph Digital Orthometric Quarter Quadrangle (DOQQ). Using the Illustrator pencil tool, the contours were manually edited based upon operator local knowledge and bathymetric contouring expertise. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Mark Hansen
    Oceanographer
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    mhansen@usgs.gov
    Date: 13-Oct-2020 (process 2 of 2)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Hansen, Mark DeWitt, Nancy T., 2002, High Resolution Bathymetric Mapping: USGS South Florida Information Access (SOFIA) Web report, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

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

  1. How well have the observations been checked?
    The accuracy of the data is determined during data collection. This dataset is derived from a single research cruise using identical equipment, set-ups, and staff; therefore, it is internally consistent. Methods are employed to maintain data collection consistency aboard the platform. During mobilization, each piece of equipment is isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements are recorded manually and digitally entered into their respective programs. Offsets between the single-beam transducers and the Ashtech antenna reference point (ARP) were measured and accounted for in post-processing. Bar checks were performed as calibration efforts and accounted for any drift in the Marimatech Echosounder. Differential Geographic Positioning System (DGPS) coordinates were obtained using post-processing software packages developed by the National Oceanic and Atmospheric Administration (NOAA)/National Geodetic Survey (NGS) Online Positioning User Service (OPUS), National Aeronautics and Space Administration (NASA)/Jet Propulsion Laboratory (JPL) GNSS-Inferred Positioning System (GIPSY), and Scripps Orbit and Permanent Array Center (SOPAC) Online Positioning User Service. Boat trajectories were computed with PNAV v2.0 software, created by Ashtech, Inc. These bathymetric data have not been independently verified for accuracy.
  2. How accurate are the geographic locations?
    The GPS antenna and receiver acquisition configuration used at the reference station was duplicated on the survey vessel (rover). The base receiver and the rover receiver record their positions concurrently at 1 Hz recording intervals throughout the survey. All processed measurements are referenced to the base station coordinates.
    GPS base or differential reference stations were operated within approximately 15 to 20 km of the survey area. Ten new, temporary ground-control points or benchmarks (surveyed to within 1- to 2-cm accuracy) were established throughout the study area for use as reference receiver sites using standard benchmark procedures. The new benchmarks were surveyed using Ashtech Z-12, 12 channel dual-frequency GPS receivers. Full-phase carrier data were recorded on each occupied benchmark in Ashtech proprietary BIN format with daily occupations ranging from 6 to 12 hours. BIN files were then converted to RINEX-2 format for position processing.
    All static base station GPS sessions were submitted for processing to the online OPUS, GIPSY, and SCOUT systems. The computed base location results were entered into a spreadsheet to compute one final positional coordinate and error analysis for that base location. The final positional coordinate (latitude, longitude, and ellipsoid height) is the weighted average of all GPS sessions. For each GPS session, the weighted average was calculated from the total session time in seconds; therefore, longer GPS occupation times held more value than shorter occupation times. Results were computed relative to the ITRF00 coordinate system. The established geodetic reference frame for the project was WGS84. Therefore, final reference coordinates used to process the rover data were transformed from ITRF00 to WGS84 using NOAA/NGS HTDP software v2.1.
    OPUS, GIPSY, and SCOUT results provide an error measurement for each daily solution. Applying these error measurements, the horizontal accuracy of the base station is estimated to be 0.04 (m) root mean squared (RMS).
    The kinematic (rover) trajectories were processed using PNAV v2.0, by Ashtech, Inc. A horizontal error measurement, RMS, is computed for each epoch. The horizontal trajectory errors varied between 0 and 0.08(m).
    The combined horizontal error from base station coordinate solutions and rover trajectories range from 0 and 0.12 (m), with the average being approximately 0.06 (m).
  3. How accurate are the heights or depths?
    The GPS antenna and receiver acquisition configuration used at the reference station was duplicated on the survey vessel (rover). The base receiver and the rover receiver record their positions concurrently at 1 Hz recording intervals throughout the survey. All processed measurements are referenced to the base station coordinates.
    GPS base or differential reference stations were operated within approximately 15 to 20 km of the survey area. Ten new, temporary ground-control points or benchmarks (surveyed to within 1 cm to 2 cm accuracy) were established throughout the study area for use as reference receiver sites using standard benchmarks procedures. The new benchmarks were surveyed using Ashtech Z-12, 12 channel dual-frequency GPS receivers. Full-phase carrier data were recorded on each occupied benchmark in Ashtech proprietary BIN format with daily occupations ranging from 6 to 12 hours. BIN files were then converted to RINEX-2 format for position processing.
    All static base station GPS sessions were submitted for processing to the online OPUS, GIPSY, and SCOUT system software. The computed base location results were entered into a spreadsheet to compute one final positional coordinate and error analysis for that base location. The final positional coordinate (latitude, longitude, and ellipsoid height) is the weighted average of all GPS sessions. For each GPS session, the weighted average was calculated from the total session time in seconds; therefore, longer GPS occupation times held more value than shorter occupation times. Results were computed relative to ITRF00 coordinate system. The established geodetic reference frame for the project was WGS84. Therefore, final reference coordinates used to process the rover data were transformed from ITRF00 to WGS84 using National Oceanic and Atmospheric Administration/National Geodetic Survey(NOAA/NGS) HTDP software v2.1.
    OPUS, GIPSY, and SCOUT results provide an error measurement for each daily solution. Applying these error measurements, the vertical accuracy of the base station is estimated to be 0.04 (m) root mean squared (RMS).
    The kinematic (rover) trajectories were processed using PNAV v2.0, by Ashtech, Inc. A vertical error measurement, RMS, is computed for each epoch. The vertical trajectory errors varied between 0 and 0.08(m).
    The combined vertical error from base station coordinate solutions and rover trajectories range from 0 to 0.14 (m), with the average approximately 0.08 (m).
  4. Where are the gaps in the data? What is missing?
    These are complete post-processed x,y,z bathymetric data points collected in 2001 from Lake Okeechobee, Florida, using an acoustic single-beam system.
  5. How consistent are the relationships among the observations, including topology?
    This dataset was acquired on a single research cruise in 2001, which was equipped with identical hardware and software systems.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints:
The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data.
Use_Constraints: These data should not be used for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    Mark E. Hansen
    U.S. Geological Survey
    Oceanographer
    600 Fourth St. South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    (727) 502-8032 (FAX)
    mhansen@usgs.gov
  2. What's the catalog number I need to order this data set? Single-beam bathymetry, vessel (R/V Streeterville) acquired, bathymetric data.
  3. What legal disclaimers am I supposed to read?
    The data have no explicit or implied guarantees. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
U.S. Geological Survey
Attn: Mark Hansen
Oceanographer
600 4th Street South
St. Petersburg, FL
USA

(727) 502-8000 (voice)
mhansen@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/DS1031-LOkee_WGS84_NAVD88-G99_metadata.contours.faq.html>
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