Ground Penetrating Radar and Global Positioning System Data Collected from Central Florida Gulf Coast Barrier Islands, Florida, February-March 2021

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Frequently anticipated questions:

What does this data set describe?

Title:
Ground Penetrating Radar and Global Positioning System Data Collected from Central Florida Gulf Coast Barrier Islands, Florida, February-March 2021
Abstract:
A morphologically diverse and dynamic group of barrier islands along the Central Florida (FL) Gulf Coast (CFGC) form a 75-kilometer-long chain stretching from Anclote Key in the north to Egmont Key in the south. In 2021, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted ground penetrating radar (GPR) surveys on barrier islands located along the CFGC, in Pinellas County, FL. This study investigated the past evolution of the CFGC from field sites at Anclote Key, Caladesi and Honeymoon Islands, and Fort DeSoto to quantify changes that occurred along these barrier systems prior to the 20th century.
Supplemental_Information:
Data were collected during USGS FAN 2021-308-FA. Additional survey and data details are available from the U.S. Geological Survey Coastal and Marine Geoscience Data System (CMGDS) at https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-308-FA.
  1. How might this data set be cited?
    Forde, Arnell S., and Bernier, Julie C., 20240312, Ground Penetrating Radar and Global Positioning System Data Collected from Central Florida Gulf Coast Barrier Islands, Florida, February-March 2021:.

    This is part of the following larger work.

    Forde, Arnell S., Bernier, Julie C., Buster, Noreen A., Ciarletta, Daniel J., and Miselis, Jennifer L., 20240312, Ground Penetrating Radar Data and Elevation-Corrected Profiles Collected in 2021 From Central Florida Gulf Coast Barrier Islands: U.S. Geological Survey data release doi:10.5066/P9NV5NAP, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -82.8504
    East_Bounding_Coordinate: -82.7144
    North_Bounding_Coordinate: 28.1784
    South_Bounding_Coordinate: 27.6214
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 17-Feb-2021
    Ending_Date: 08-Mar-2021
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: DZT, tabular, vector, and raster 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 (120)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 17
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -81.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in Meter
      The horizontal datum used is North American Datum 1983.
      The ellipsoid used is Geodectic Reference System 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:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum 1988
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meter
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    2021-308-FA_gpr_traces.zip
    File containing the raw, unprocessed GPR profile data exported in ASCII 4-column format. Many XYZ processing programs do not accept column header labels; therefore, they were not included in these files. The column headers are as follows: Column 1 = Horizontal distance (meters), Column 2 = Elevation (meters), Column 3 = Two-way travel time (nanoseconds), and Column 4 = Amplitude (Megahertz). (Source: USGS)
    Horizontal distance
    This column indicates the location, in meters, from the start (0) to the end of the GPR profile and can be used to locate the position of reflections. The linear distance data were collected using a 16-inch survey wheel. (Source: Reflexw) Values start with 0 (the beginning of the profile) and end with the total distance (m) covered by the profile.
    Elevation
    Elevation data were not recorded directly to the GPR trace headers but were saved separately within the navigation GGA string. (Source: Reflexw) Values in this column are all zero, since elevation data were not integrated into the raw data.
    Two-way travel time
    This column records the two-way travel time, in nanoseconds, that it takes to reach a reflection surface from the source. (Source: Reflexw)
    Range of values
    Minimum:0
    Maximum:200
    Amplitude
    Amplitude of reflection, in Megahertz (Source: Reflexw) Data represents the amplitude of the reflection, which can vary widely. Values can be either negative or positive.
    2021-308-FA_GGA.zip
    File containing the processed navigation data for the GPR profiles, which were output as GGA strings for each profile. Data are comma-separated text files and do not contain column headers; column definitions are provided in the following attributes. (Source: GrafNav)
    $GPGGA
    Message ID; essential fix data that provides 3D location and accuracy. (Source: GrafNav) Attribute is a file format identification.
    UTC of position fix
    Time stamp of position fix (Coordinated Universal Time) in hhmmss.00 format, where hh = hour (in 24-hour format), mm = minutes, and ss = seconds. (Source: GrafNav) Value is the UTC time stamp and increases by 1 every second.
    Latitude
    The latitude of the XYZ point (NAD83) in DDMM.MMMMM format. (Source: GrafNav) Values are degrees of latitude, spatial data.
    Direction of latitude
    Direction of latitude is in the Northern (N) Hemisphere. (Source: GravNav) The attribute indicates that the degree of latitude is in the Northern Hemisphere.
    Longitude
    The longitude of the XYZ data point (NAD83) in DDMM.MMMMM format. (Source: GrafNav) Values are degrees of longitude, spatial data.
    Direction of longitude
    Direction of longitude is in the Western (W) Hemisphere. (Source: GrafNav) The attribute indicates that the degree of longitude is in the Western Hemisphere.
    GPS Quality indicator 0: Fix not valid 1: GPS fix 2: Differential GPS fix, OmniSTAR VBS 4: Real-Time Kinematic, fixed integers 5: Real-Time Kinematic, float integers, OmniSTAR XP/HP or Location RTK
    Defines the type and quality of the GPS data. Occasionally, GPS quality indicator values were not recorded by the acquisition system to the raw GGA string; consequently, these fields are displayed as blank/empty attributes in the final navigation files. (Source: GrafNav)
    Range of values
    Minimum:0
    Maximum:5
    Number of satellites in view
    Number of satellites utilized by the program to process the data. Occasionally, values were not recorded by the acquisition system to the raw GGA string; consequently, these fields are displayed as blank/empty attributes in the final navigation files. (Source: GrafNav)
    Range of values
    Minimum:00
    Maximum:24
    HDOP
    Horizontal Dilution of Precision (HDOP) expresses the effect of satellite positions on the precision of the reported positions. < 1 = Ideal, 1-2 = Excellent, 2-5 = Good, 5-10 = Moderate, 10-20 = Fair, > 20 = Poor. (Source: GrafNav)
    Range of values
    Minimum:0
    Maximum:20
    Orthometric height (Mean Sea Level (MSL) reference)
    Height of the XYZ position in reference to NAVD88, using GEOID18. (Source: GrafNav) Elevation above GEOID18, in meters.
    M
    Unit of measure used for the orthometric height. (Source: GrafNav) The orthometric height is reported in meters.
    Geoid separation
    Height of GEOID (MSL) above the ellipsoid. (Source: GrafNav) Separation between GEOID18 and the reference NAD83 ellipsoid, in meters.
    M
    Unit of measure used for the GEOID separation. (Source: GrafNav) The GEOID separation is reported in meters.
    Age of differential GPS data record
    Time, in seconds, since last GPS update. (Source: GrafNav) This field is required by the GGA string; however, only null values were recorded by the acquisition system for every line collected during the survey. This attribute is displayed as blank/empty in the final navigation files.
    Reference station ID
    Refers to the reference station used to process the GPS data presented in this dataset. (Source: GrafNav) Values vary depending upon station used. A null value is utilized when any reference station ID is selected and no corrections are received.
    Checksum data
    The value of the checksum data used to detect errors; this field always begins with *. (Source: GrafNav) The checksum is the hexadecimal representation of two hexadecimal characters of an XOR of all the bytes between [$] and [*], not including the delimiters.
    2021-308-FA_profile_images.zip
    File contains the JPEG images of the processed GPR profiles with the elevation and radar-wave velocity corrections applied. (Source: USGS)
    2021-308-FA_tracklines.zip
    Geospatial data representation showing the locations of all the GPR tracklines collected from CFCG barrier islands, during 2021-308-FA. Geographic Information System (GIS) files are provided in Esri shapefile (.shp) and Keyhole Markup Language (KML) formats. Location maps in JPEG format are also included. (Source: USGS)
    2021-308-FA_profile_parameters.zip
    Microsoft Excel Worksheet (.xlsx) and comma-separated values (.csv) file containing profile-specific data acquisition and processing parameters for each GPR profile. Attributes listed below (except for: Velocity_m/ns, Dielectric, ExportVel_m/ns, DisplayGain, and ElevationSource) also apply to the trackline GIS files described above. (Source: USGS)
    LineID
    GPR trackline number (Source: USGS)
    Range of values
    Minimum:001
    Maximum:120
    DateColl
    Date the GPR trackline data were collected, written as M/DD/YYYY (1-digit month, 1- or 2-digit day, and 4-digit year). (Source: USGS)
    Range of values
    Minimum:2/17/2021
    Maximum:3/8/2021
    DOY
    Day of year, as represented on the Julian calendar, the data were collected. (Source: USGS)
    Range of values
    Minimum:048
    Maximum:067
    Range_ns
    Range is the maximum two-way travel time, in nanoseconds (ns), that is viewed during data collection. For this survey, lines were collected with a range of 100 or 200 ns. (Source: USGS)
    Range of values
    Minimum:100
    Maximum:200
    TowedBy
    Describes whether the GPR antenna was pulled on foot or towed behind a vehicle. (Source: USGS)
    ValueDefinition
    on footGSSI was pulled over terrain, on foot, by USGS staff.
    vehicleGSSI was towed behind a survey vehicle (a utility task vehicle or UTV) , at approximately 4-5 miles per hour.
    on foot/vehicleGSSI was towed behind the UTV or pulled by a USGS employee on foot.
    Location1
    Identifies the local study area from which the GPR profile was collected. (Source: USGS)
    ValueDefinition
    Fort De SotoData were acquired within Fort De Soto Park, which is operated by Pinellas County, Florida.
    Honeymoon and Caladesi IslandsData were acquired within Honeymoon and Caladesi Island State Parks, which are operated by the Florida Department of Environmental Protection.
    Anclote KeysData were acquired within Anclote Key Preserve State Park, which is operated by the Florida Department of Environmental Protection.
    Location2
    Describes the coastal setting or barrier island from which the GPR profile was collected. (Source: USGS)
    ValueDefinition
    St. Jean Key (SJK)St. Jean Key (SJK), FL barrier island
    Cabbage Key (CK)Cabbage Key (CK), FL barrier island
    Mullet Key (MK)Mullet Key (MK), FL barrier island
    Honeymoon Island (HI)Honeymoon Island (HI), FL barrier island
    Caladesi Island (CI)Caladesi Island (CI), FL barrier island
    Anclote Key (AK)St. Anclote Key (AK), FL barrier island
    Description
    Physical description, including orientation and terrain, of the environment from which the GPR profile was collected. Due to ArcMap character limitations, this attribute is listed as “Descriptio” in the GIS files (.shp). (Source: USGS) Data were collected within residential, state and county parks, and wilderness areas on various CFCG barrier islands.
    SurfaceType
    Qualitative description of the predominant surface material along the GPR profile. Due to ArcMap character limitations, this attribute is listed as “SurfaceTyp” in the GIS files (.shp). (Source: USGS) Surface materials were observed in the field. Surface types encountered during these surveys included: pavement, pavement/shoulder, unpaved road, soil/shoulder, soil/pavement, soil/grass, soil, sand, unpaved shoulder, sand/paved, paved, paved/soil, unpaved road (sand), and sand/soil.
    Length_m
    Measured length of the GPR profile, in meters, which was calculated by GIS software. (Source: USGS)
    Range of values
    Minimum:48.25
    Maximum:1130.63
    MinElev_m
    Minimum elevation along the GPR profile, in meters, relative to NAVD88 (GEOID18). (Source: USGS)
    Range of values
    Minimum:0.0
    Maximum:1.566
    MaxElev_m
    Maximum elevation along the GPR profile, in meters, relative to NAVD88 (GEOID18). (Source: USGS)
    Range of values
    Minimum:0.096
    Maximum:3.504
    Velocity_m/ns
    Radar-wave velocity through the sediment, in meters per nanosecond, estimated from hyperbola analyses along each profile. (Source: USGS)
    Range of values
    Minimum:0.05
    Maximum:0.60
    Dielectric
    The dielectric constant of the sediment, calculated from the radar-wave velocity. This is a dimensionless value. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:36
    ExportVel_m/ns
    Radar-wave velocity, in meters per nanosecond, applied to individual profiles during export to create elevation- and velocity-corrected profiles. (Source: USGS)
    Range of values
    Minimum:0.06
    Maximum:0.20
    ExportVel2
    Radar-wave velocity, in meters per nanosecond, applied to individual profiles during export to create elevation- and velocity-corrected profiles. (Source: USGS)
    Range of values
    Minimum:0.19
    Maximum:0.19
    DisplayGain
    The display gain applied, if any, to enhance contrast in the elevation- and velocity-corrected profiles. This is a dimensionless value. (Source: USGS)
    Range of values
    Minimum:-6
    Maximum:6
    ElevSource
    Identifies the data source used for elevation values included in each GPR profile. (Source: USGS)
    ValueDefinition
    GPSElevation values were derived using differentially corrected GPS.
    2021 LidarElevation values were derived from NGS lidar data collected in January 2021 (NGS, 2022).
    2015 LidarElevation values were derived from USACE lidar data collected in June 2015 (USACE JALBTCX, 2016).
    ElevSource2
    Identifies the data source used for elevation values included in each GPR profile. (Source: USGS)
    ValueDefinition
    N/ANot applicable
    Entity_and_Attribute_Overview:
    The entity and attribute information provided here describes the tabular data associated with the dataset. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the dataset.
    Entity_and_Attribute_Detail_Citation:
    The entity and attribute information were generated by the individual and/or agency identified as the originator of the dataset. Please review the rest of the metadata record for additional details and information.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Arnell S. Forde
    • Julie C. Bernier
  2. Who also contributed to the data set?
    Funding and (or) support for this study were provided by the USGS Coastal and Marine Hazards and Resources Program. The authors thank Nancy DeWitt for her assistance in survey coordination and data collection. This document was improved by scientific/editorial and metadata reviews from Christopher Smith and Tess Rivenbark-Terrano of the St. Petersburg Coastal and Marine Science Center.
  3. To whom should users address questions about the data?
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Attn: Arnell S. Forde
    Geologist
    600 4th Street South
    St. Petersburg, FL

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

Why was the data set created?

The data release associated with this metadata record serves as an archive of GPR and geospatial data collected from back-barrier environments at Anclote Key (AK), Caladesi Island (CI), Honeymoon Island (HI), Cabbage Key (CK), Mullet Key (MK), and St. Jean Key (SJK) from February 17–March 8, 2021 (USGS Field Activity Number (FAN) 2021-308-FA). Sedimentologic (vibracore) data were also collected in February and May 2021 to characterize and age-date the subsurface sedimentology; those data will be made available as a separate data release. GPR data can be used to map shallow subsurface sediments such as erosional surfaces or washover deposits and can also be used to image deeper stratigraphic features that may aid in linking terrestrial geology to nearshore and offshore geologic features. This dataset was used to support analyses provided in Ciarletta and others (2023) and will also be used to calibrate a model of barrier island development, quantifying historic sediment fluxes within the Pinellas barrier island system. Additional information regarding data acquisition and processing methods are provided in Forde and others (2018).

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: 2021 (process 1 of 4)
    Navigation data acquisition - Position and elevation data for each GPR line were recorded at the time of collection using a Spectra Precision SP90M GPS receiver and geodetic antenna. GPS data were recorded concurrently throughout the survey using a SP90M receiver and Trimble Zephyr-3 Base antenna at base stations set up on local benchmarks at the Fort DeSoto flagpole (NGS identifier AG0484; CK, MK, and SJK lines) or along the Dunedin Causeway at Hog Island (NGS identifier AL0220; CI, HI, and AK lines). The rover unit was mounted 1.320 m above the GPR antenna and was connected to the GPR's digital control unit. Raw GPS positions were output to the GPR control unit in real time as a National Marine Electronics Association (NMEA) GGA string at 0.5-second (s) intervals using coordinated universal time (UTC) stamps and saved as a .PLT data file. Person who carried out this activity:
    Julie C. Bernier
    U.S. Geological Survey
    Geologist
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jbernier@usgs.gov
    Date: 2021 (process 2 of 4)
    GPR data acquisition - A total of 120 GPR lines (lines 001-019 and 048-053 for SJK; 020-024 for CK; 025-047 for MK; 054-084 for HI; 085-106 for CI; and 107-120 for AK), representing a linear distance of approximately 40.5 km, were acquired during USGS FAN 2021-308-FA within developed and undeveloped beach, dune, and back-barrier environments at the CFCG study sites. Data were collected along established roads, beach accesses, and along hiking trails through back-barrier scrub/shrub vegetation. The GPR data were collected with a Geophysical Survey Systems, Inc. (GSSI) TerraSIRch SIR System-3000, which acquires single-channel GPR data and includes a Digital Control Unit (model DC-3000) and 200-Megahertz (MHz) antenna. A 16-inch survey wheel (GSSI model 620) was attached to the back of the antenna and calibrated prior to surveying to ensure an accurate revolution-of-wheel to distance ratio. Distance mode was used to record the raw GPR data and the raw GGA position string was recorded in real time via an Acumen SDR data logger. GPR traces were collected at a maximum rate of 64 scans per second with a vertical resolution of 1,024 samples per scan and an Infinite Impulse Response (IIR) filter was used (Lowpass = 600 MHz, Highpass = 50 MHz) to increase the signal-to-noise ratio of the recorded GPR data (Forde and others, 2018). Data were acquired using the SIR 3000 in TerraSIRch mode and saved in GSSI's proprietary Data Zero Time (DZT) format. Person who carried out this activity:
    Julie C. Bernier
    U.S. Geological Survey
    Geologist
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jbernier@usgs.gov
    Date: 2023 (process 3 of 4)
    Navigation processing - Base station data were post-processed through the NGS Online Positioning User Service (OPUS, https://geodesy.noaa.gov/OPUS/). The time-weighted coordinates calculated from all base-station occupations at AG0484 and AL0220 were used for post-processing. The base station coordinates were imported into GrafNav, version 8.9 (NovAtel Waypoint Product Group), and the data from the rover GPS were post-processed to the concurrent base-station session data. The final, differentially corrected, GPS positions were computed at 0.5-s intervals for each rover GPS session. For lines 001-003, 007-008, and 014, the post-processed navigation data were exported in American Standard Code for Information Interchange (ASCII) text format as a NMEA GGA string, which replaced the uncorrected real-time rover positions recorded during acquisition. Along most GPR lines, however, there were significant dropouts (possibly attributed to atmospheric conditions and (or) the height of the back-barrier vegetation relative to the height of the rover antenna) that resulted in large gaps in the post-processed navigation data, especially in back-barrier environments (Forde and others, 2018). Along these lines, elevations at the raw rover x,y coordinates were interpolated from lidar data collected by the U.S. Army Corps of Engineers (USACE) in June 2015 (USACE JALBTCX, 2016) or, for SJK only, lidar data collected by the National Geodetic Survey (NGS) in January 2021 (NGS, 2022) using Esri ArcMap version 10.8.1. Visual and quantitative comparison of post-processed and lidar elevation profiles along each GPR line showed satisfactory agreement and acceptable 2-sigma values, please see the positional accuracy report for additional details. The elevation values in the raw navigation string were replaced with post-processed (beach and dune environments) or lidar (everywhere else) elevations; the NMEA checksum string was recalculated for each navigation string in Matlab version R2021A. Processed navigation data are provided in the North American Datum of 1983 (NAD83) (2011) coordinate system and processed orthometric elevations are reported relative to the North American Vertical Datum of 1988 (NAVD88), derived using the GEOID18 geodetic model. The final navigation files provided in the data release were saved as ASCII text format (.gga) data files. Person who carried out this activity:
    Julie C. Bernier
    U.S. Geological Survey
    Geologist
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jbernier@usgs.gov
    Data sources produced in this process:
    • 2021-308-FA_GGA.zip
    Date: 2023 (process 4 of 4)
    GPR processing - Reflexw Version 7.2.2 (Sandmeier Scientific Software) geophysical near-surface processing and interpretation software was used to process the GPR data. GPR data were acquired in DZT format and later imported into Reflexw, where they were converted into a DAT file. For archival purposes, a non-proprietary version of the raw data was created by exporting the DAT file from Reflexw and saving it in ASCII 4-column format (.asc). The data were processed in a consistent order: (1) static correction was applied; (2) the mean value was subtracted (dewowed); (3) header gain applied during acquisition was removed; (4) manual Automatic Gain Control (AGC) gain was applied; and (5) post-processed navigation data were imported into the trace headers. Data were visually inspected after each step listed above and before elevation-corrected subsurface profiles were exported; all profiles were analyzed for errors or data gaps in the navigation and trace data to ensure data quality was maintained throughout. Hyperbola analyses were performed on all profiles to estimate the radar-wave velocities through the sediment. Calculated velocities at AK (N=13) ranged from 0.06 to 0.60 meters/nanosecond (m/ns) and, excluding three statistical outliers, averaged 0.10 m/ns. Calculated velocities at HI and CI (N=51) ranged from 0.05 to 0.30 m/ns. Velocities at HI-CI clustered into two groups (v < 0.10 m/ns and v >= 0.10 m/ns) with average values of 0.06 and 0.19 m/ns, respectively. Calculated velocities at CK, MK, and SJK (N=50) ranged from 0.05 to 0.20 m/ns. Velocities at CK-MK-SJK clustered into two groups (v <= 0.10 m/ns and v >= 0.15 m/ns) with average values of 0.07 and 0.20 m/ns, respectively. The processed profile data were re-imported into GSSI RADAN version 7.5.18 software and the surface normalization processing algorithm was applied, adjusting the profile to both the measured terrain and the site-specific radar-wave velocities. The elevation- and velocity-corrected profiles are provided as DZT-formatted files and were also exported as Joint Photographic Experts Group (JPEG) images. Some GPR lines were mostly or completely attenuated; for those lines elevation-corrected profile images are not provided in the data release. The processed trace data (.asc, .dzt, .dzx) for all 120 lines have been provided in the data release. Processed GPR profile trackline files were exported from RADAN 7 in Keyhole Markup Language (KML) format, projected to the Universal Transverse Mercator (UTM) 17 North (17N) coordinate system, and appended with profile-specific data acquisition and processing parameters in Esri ArcMap version 10.8.1. Person who carried out this activity:
    Arnell S. Forde
    U.S. Geological Survey
    Geologist
    600 4th Street South
    St.Petersburg, FL

    (727)502-8000 (voice)
    aforde@usgs.gov
    Data sources produced in this process:
    • 2021-308-FA_gpr_traces.zip
    • 2021-308-FA_RADAN.zip
    • 2021-308-FA_profile_images.zip
    • 2021-308-FA_tracklines.zip
  3. What similar or related data should the user be aware of?
    Forde, Arnell S., Bernier, Julie C., and Miselis, Jennifer L., 20180221, Ground Penetrating Radar and Differential Global Positioning System Data Collected in April 2016 From Fire Island, New York: U.S. Geological Survey Data Series 1078, U.S. Geological Survey, Reston, VA.

    Online Links:

    Ciarletta, Daniel J., Miselis, Jennifer L., Bernier, Julie C., Forde, Arnell S., and Mahan, Shannon A., 2023, Reconstructing the geomorphic evolution and sediment budget history of a dynamic barrier island: Anclote Key, Florida: Proceedings of the Coastal Sediments 2023, New Orleans, Louisiana, April 11-15, 2023 p. 1-11 in Wang, P., Royer, E., and Rosati, J.D., (eds.), World Scientific Publishing, Hackensack, NJ.

    Online Links:

    U.S. Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical Center of eXpertise (JALBTCX), and NOAA Office for Coastal Management (NOAA/OCM), 2016, 2015 USACE NCMP Topobathy Lidar DEM: Florida Gulf Coast.

    Online Links:

    National Geodetic Survey (NGS), 2022, 2021 NOAA NGS Topobathy Lidar DEM: Southern Tampa Bay, Florida.

    Online Links:

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

  1. How well have the observations been checked?
    Visual inspection of the GPR profile images rendered from the data did not show any major anomalies. Latitude, longitude, and elevation values included in the final navigation files were manually checked and verified by the processor.
  2. How accurate are the geographic locations?
    When possible, location information associated with each GPR profile was determined by post-processed differential correction using a base/rover setup. Processing the full-carrier phase data allows precise positioning of the base and rover receivers. Differential processing improves the rover positions by assessing positional errors computed at the base receiver and applying those errors or differences to the rover receiver. Forward and backward time-series processing of the kinematic (rover) data provides an independent calculation of the baseline trajectory and rover position relative to the base station; the positional accuracy can be estimated by differencing the time series (position separation). For lines 001-003, 007-008, and 014, the estimated post-processed horizontal accuracy (2-sigma) was 0.012 +/- 0.013 meters (m). Along most GPR lines, however, there were significant global positioning system (GPS) dropouts that resulted in large gaps in the post-processed navigation data, especially in back-barrier environments. Along these lines, the raw rover x,y coordinates were used. The manufacturer's specified real-time accuracy of the Spectra Precision SP90M rover is 0.25 m + 1 part-per-million (ppm); visual inspection showed offsets between raw and post-processed horizontal position data of up to 1.5 m.
  3. How accurate are the heights or depths?
    As described above, location information associated with lines 001-003, 007-008, and 014 was determined by post-processed differential correction using a base/rover setup. For these lines, the estimated post-processed vertical accuracy (2-sigma) was 0.020 +/- 0.016 m. Along the remaining lines where significant GPS dropouts resulted in large gaps in the post-processed navigation data, elevations at the raw rover x,y coordinates were interpolated from light detection and ranging (lidar) data collected by the U.S. Army Corps of Engineers (USACE) in June 2015 (USACE JALBTCX, 2016) or, for SJK only, lidar data collected by the National Geodetic Survey (NGS) in January 2021 (NGS, 2022). Comparison of post-processed and lidar elevation profiles along each GPR line showed suitable agreement; therefore, the elevation values in the raw navigation string were replaced with post-processed (beach and dune environments) or lidar (everywhere else) elevations. The estimated vertical accuracy (2-sigma) of all post-processed elevations was 0.025 +/- 0.021 m; the average difference between lidar and post-processed elevations was 0.029 +/- 0.099 m (2-sigma).
  4. Where are the gaps in the data? What is missing?
    A total of 120 GPR lines (lines 001-019 and 048-053 for SJK; 020-024 for CK; 025-047 for MK; 054-084 for HI; 085-106 for CI; and 107-120 for AK), representing a linear distance of approximately 40.5 kilometers (km), were acquired during USGS field activity number 2021-308-FA.
  5. How consistent are the relationships among the observations, including topology?
    This dataset is from one field activity with consistent instrument calibrations.

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 Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originators of the data in future products or derivative research. Users are advised to read the metadata record thoroughly to understand appropriate use and data limitations.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Attn: USGS SPCMSC Data Management
    600 4th Street South
    Saint Petersburg, FL
    United States

    727-502-8000 (voice)
    gs-g-spcmsc_data_inquiries@usgs.gov
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    This publication was prepared by an agency of the United States Government. Although these data were processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  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 profile parameters files were created in Microsoft Excel for Mac, version 16.71 and can be opened using Microsoft Excel 2007 or higher; these data are also provided as comma-separated values (.csv) text files. The GPR profile trackline locations are provided as GIS data files in Esri shapefile (.shp) and Keyhole Markup Language (KML) formats; these files may also be viewed with QGIS (https://www.qgis.org/en/site/, 2024), Google Earth (https://www.google.com/earth/) or other GIS software capable of importing the data. Post-processed navigation (.gga) and unprocessed GPR trace data (.asc) provided in ASCII format can be accessed with any standard text editor. Processed GPR subsurface profile data output using RADAN (.dzt and .dzx) can be opened and viewed by any software capable of reading GPR trace data.

Who wrote the metadata?

Dates:
Last modified: 12-Mar-2024
Metadata author:
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Attn: USGS SPCMSC Data Management
600 4th Street South
Saint Petersburg, FL
United States

727-502-8000 (voice)
gs-g-spcmsc_data_inquiries@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/2021-308-FA_GPR_metadata.faq.html>
Generated by mp version 2.9.51 on Tue Mar 12 13:38:05 2024