Single-Beam Bathymetry Sounding Data of Lake Okeechobee, Florida (2001) in XYZ format

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Frequently anticipated questions:


What does this data set describe?

Title:
Single-Beam Bathymetry Sounding Data of Lake Okeechobee, Florida (2001) in XYZ 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 (1890 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 boating 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 mostly from agricultural activities.
High-resolution bathymetric mapping was conducted in 2001 in Lake Okeechobee by the USGS, in cooperation with 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 of 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 was collected in a minimum of 0.6 meters water depth except where there is 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 data products include XYZ data, bathymetric contours, 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 Bathymetry Sounding Data of Lake Okeechobee, Florida (2001) in XYZ 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: -81.01014
    East_Bounding_Coordinate: -80.61415
    North_Bounding_Coordinate: 27.21394
    South_Bounding_Coordinate: 26.71152
  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: tabular digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (519383)
    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 WGS84-G1150.
      The ellipsoid used is WGS84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
      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.xyz.txt, DS1031-LOkee_WGS84_NAVD88-G99_SB.xyz.shp
    Post-processed, area-specific x,y,z attributed single-beam bathymetry data. (Source: USGS)
    FID
    Field ID (Source: USGS) Sequential unique whole numbers that are automatically generated.
    longitude (WGS84)
    WGS84 (G1150) x-coordinate (easting) of sample point (Source: NOAA/NGS UTMS)
    Range of values
    Minimum:-81.01014
    Maximum:-80.61415
    Units:decimal degrees
    Resolution:0.00000001
    latitude (WGS84)
    WGS84 (G1150) y-coordinate (northing) of sample point (Source: NOAA/NGS UTMS)
    Range of values
    Minimum:26.71152
    Maximum:27.21394
    Units:decimal degrees
    Resolution:0.00000001
    ellipsoid height (WGS84)
    WGS84 (G1150) ellipsoid height of sample point, in meters (Source: SANDS)
    Range of values
    Minimum:-29.937
    Maximum:-20.59
    Units:meters
    Resolution:0.001
    NAVD88 (G99)
    Orthometric height of sample point, in meters. Relative to geoid model Geoid99. (Source: SANDS)
    Range of values
    Minimum:-3.302
    Maximum:5.566
    Units:meters
    Resolution:0.001

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 4)
    Data Acquisition - The seafloor of Lake Okeechobee was mapped by using an outboard motor boat, equipped with a high-precision Global Positioning Systems (GPS) coupled with a high-precision depth sounder. To accomplish this task, the System for Accurate Nearshore Depth Surveying (SANDS) system was developed by Mark Hansen (SPCMSC) and Jeff List (WHSC) of the U.S. Geological Survey. SANDS consists of two components, hardware and processing software.
    Survey tracklines were spaced 500-meters apart and orientated in a north/south orientation. Tracklines collected parallel to the lake shoreline (intersecting tracklines) functioned to serve as a cross-check and to assess the relative vertical accuracy of the survey. Crossing lines are critical because they serve as a check on the internal accuracy of the data. Soundings were collected along each trackline at 3-m spacing. In shallow areas, data were collected in a minimum of 0.3 m water depth except where there was potential damage to the bottom environment or the boat/motors.
    Reference GPS reference stations were operated of an USGS benchmark, typically located within approximately 15 km of the farthest single-beam trackline. Reference and rover GPS receivers recorded the 12-channel full-carrier-phase positioning signals (L1/L2) from satellites via Ashtech choke-ring antennas. The reference and rover receivers record their positions concurrently at 1-second(s) recording intervals throughout the survey.
    Boat motion was recorded at 50-millisecond (ms) intervals using a TSS Dynamic Motion Sensor 05 (TSS DMS-05). Bathymetric soundings were recorded at 10-ms intervals using a Marimatech EC-100 survey grade echo-sounder. The single-beam data were acquired using the hydrographic software HYPACK version 5. All data strings from the instruments were streamed in real time and recorded through HYPACK software. 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
    Data sources produced in this process:
    • Raw sensor data files in ASCII text format and GPS Carrier-phase data in binary format.
    Date: 2001 (process 2 of 4)
    Differentially Corrected Navigation Processing- The coordinate values of the reference GPS base stations obtained from OPUS were provided in the ITRF00 coordinate system. All survey data for the project was referenced to WGS84. Consequently, reference station coordinates were transformed to WGS84 coordinates using the NOAA/NGS software HTDP v1.3. The respective reference (base) station coordinates utilized as reference positions were imported into PNAV v2.0 software by Ashtech, Inc. Differentially-corrected rover trajectories were computed by merging the master and rover to the GPS data. During processing, steps were taken to ensure that the trajectories between the base and rover were clean, resulting in fixed positions. By analyzing the graphs, trajectory maps, and processing logs that GrafNav produces for each GPS session, GPS data from satellites flagged by the program as having poor health or satellite time segments that had cycle slips could be excluded, or the satellite elevation mask angle could be adjusted to improve the position solutions. The final differentially corrected precise DGPS positions were computed for each rover GPS session and exported in ASCII text format. Person who carried out this activity:
    Mark Hansen
    U.S. Geological Survey
    Oceanographer
    600 Fourth St. South
    St. Petersburg, FL

    727-502-8000 (voice)
    727-502-8032 (FAX)
    mhansen@usgs.gov
    Data sources produced in this process:
    • Boat trajectory data files in ASCII text format.
    Date: 2001 (process 3 of 4)
    Single-beam Bathymetry Processing- All data were processed using SANDS version 1.2. The primary purpose of SANDS is to time synchronize processed trajectories, soundings, and heave/pitch/roll, then merges all data strings. SANDS applies latency errors, applies geometric corrections for antenna staff pitch and roll, applies geometric corrections for antenna transducer pitch and roll (beam correction), time synchronizes the GPS trajectory and HYPACK files for each GPS epoch, and converts WGS84 latitude/longitude coordinates to North American Datum of 1983 NAD83/GRS80 UTM coordinates (m), and applies a geoid separation based upon NOAA/NGS the Geoid99 model. Latitude/longitude conversion to UTM coordinates was accomplished using NOAA/NGS UTM v2.0 software. Intermediate output files are comma delimited text files containing: time of day (seconds of day), UTM X coordinate (m), UTM Y coordinate (m), ellipsoid height, orthometric height, smoothed raw depths, PNAV RMS value, and HYPACK line number. A header line indicates the attributes entry for each column. Person who carried out this activity:
    Mark Hansen
    U.S. Geological Survey (USGS) - St. Petersburg Coastal and Marine Science Center
    Oceanographer
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    727-502-8032 (FAX)
    mhansen@usgs.gov
    Data sources used in this process:
    • Completely processed final X,Y,Z files representing sea-floor elevations.
    Data sources produced in this process:
    • Final processed bathymetry data files in ASCII text format.
    Date: 2015 (process 4 of 4)
    The final processed bathymetry files were reformatted for publication. UTM coordinates were converted to latitude/longitude using NOAA/NGS UTMS v2.0 software. Shapefiles were created from X,Y,Z text files using in-house developed software. 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)
    (727) 502-8032 (FAX)
    mhansen@usgs.gov
    Data sources produced in this process:
    • DS1031-LOkee_WGS84_NAVD88-G99_SB.xyz.txt and DS1031-LOkee_WGS84_NAVD88-G99_SB.xyz.shp
  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) Online Positioning User Service (GIPSY), and Scripps Orbit and Permanent Array Center Online Positioning User Service (SCOUT). Boat trajectories were computed with PNAV v2.0 software 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 1Hz 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 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 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 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 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 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 for 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 for varied between 0 and 0.08(m).
    The combined vertical error from base station coordinate solutions and rover trajectories range from 0 and 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: 01-Feb-2015
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)

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