Raw and processed Ground Penetrating Radar and post-processed Differential Global Positioning System data collected from Assateague Island, Maryland, October 2014

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title:
Raw and processed Ground Penetrating Radar and post-processed Differential Global Positioning System data collected from Assateague Island, Maryland, October 2014
Abstract:
Scientists from the United States Geological Survey, St. Petersburg Coastal and Marine Science Center (USGS-SPCMS) acquired sediment cores, sediment surface grab samples, Ground Penetrating Radar (GPR) and Differential Global Positioning System (DGPS) data from Assateague Island, Maryland, in October (FAN 2014-322-FA) 2014. The objectives were to identify washover deposits in the stratigraphic record to aid in understanding barrier island evolution. The report associated with this metadata record serves as an archive of GPR and DGPS data collected from Assateague Island in October 2014. Data products and accompanying Federal Geographic Data Committee (FGDC) metadata can be downloaded from the Data Downloads page located at, http://pubs.usgs.gov/publication/ds989/ds_data_downloads.html.
Supplemental_Information: Data were collected during USGS field activity 2014-322-FA.
  1. How might this data set be cited?
    Zaremba, Nicholas J., 20151205, Raw and processed Ground Penetrating Radar and post-processed Differential Global Positioning System data collected from Assateague Island, Maryland, October 2014:.

    Online Links:

    This is part of the following larger work.

    Zaremba, Nicholas J., Bernier, Julie C., Forde, Arnell S., and Smith, Christopher G., 20151205, Ground Penetrating Radar and Differential GPS Data Collected from Assateague Island, Maryland, 2014: U.S. Geological Survey Data Series 989, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.19903
    East_Bounding_Coordinate: -75.13172
    North_Bounding_Coordinate: 38.10989
    South_Bounding_Coordinate: 38.25004
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 23-Oct-2014
    Ending_Date: 26-Oct-2014
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Tabular digital data, 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):
      • String (44)
    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 0.001. Longitudes are given to the nearest 0.001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is 500000.0.
      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.
  7. How does the data set describe geographic features?
    2014-322-FA_GPR ASCII Raw Data.zip
    File containing each raw, unprocessed GPR profile in ASCII format. Many XYZ processing programs will not accept column header labels therefore they were not placed in the file. Column 1= Horizontal distance (meters), Column 2= elevation, Column 3= two way travel time, Column 4= Amplitude. (Source: USGS)
    Horizontal distance
    This column indicates the location in meters from the start(0) to the end of the GPR profile, this column can be used to locate the postion of reflections. The distance data was collected using the distance measureing wheel. (Source: Reflexw) Values start with 0 (the begining of the profile) and end with the total distance covered by the profile, units are in meters.
    Elevation
    All values in this column are 0 as a result of elevation data being contained in the GGA string and not recorded in the ASCII file. (Source: Reflexw) Values are all zero, since elevation data has not been applied.
    two way travel time
    This column records the two way travel time in nanoseconds that it takes to reach a reflection 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.
    2014-322-FA_GPR DGPS data.zip
    File containing the processed navigation data for the GPR profiles. Data does not contain column lables Column 1= Message ID $GPGGA, Column 2= UTC of position fix, Column 3= Latitude, Column 4= Direction of latitude: N, Column 5= Longitude, Column 6= Direction of longitude: W, Column 7= 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, Column 8= Number of SVs in use, range from 00 through to 24+, Column 9= HDOP, Column 10= Orthometric height (MSL reference), Column 11= M: unit of measure for orthometric height is meters, Column 12= Geiod Seperation, Geiod 13= M: geoid separation measured in meters, Column 14= Age of differential GPS data record, Type 1 or Type 9. Null field when DGPS is not used. Column 15= Reference station ID, range 0000-4095. A null field when any reference station ID is selected and no corrections are received. Column 16= The checksum data, always begins with *. (Source: GrafNav)
    Message ID $GPGGA
    The type of file, indicates it is a GGA string. (Source: GrafNav) Attribute is a file format identification.
    UTC of position fix
    GPS time in seconds. (Source: GrafNav) Value is GPS time, increases by 1 every second.
    Latitude
    The latitude of the XYZ point, latitude is projected in UTM 18N. (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. (Source: GrafNav) Values are the degree 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 DGPS data. (Source: GrafNav)
    Range of values
    Minimum:0
    Maximum:5
    Number of SVs in use, range from 00 through to 24+
    Number of satelites utilized by the program to process the data. (Source: GrafNav)
    Range of values
    Minimum:00
    Maximum:24
    HDOP
    Horizontal Dilution of Precision (HDOP) expresses the effect of satelite postions on the precision of the reported postions. < 1 Ideal, 1-2 Excellend, 2-5 good, 5-10 moderate, 10-20 fair, >20 poor. (Source: GrafNav)
    Range of values
    Minimum:0
    Maximum:20
    Orthometric height (MSL reference)
    Height of the XYZ postion in reference to NAVD88 using GEIOD12A. (Source: GrafNav) Elevation above the GEIOD12A in meters, spatial data.
    M: unit of measure for orthometric height is meters
    The orthometric height is reported in meters. (Source: GrafNav) Indicates data is reported in meters.
    Geoid separation
    Seperation between GEIOD12A and the reference ellipsoid NAVD88 in meters. (Source: GrafNav) Seperation between GEIOD12A and the reference ellipsoid NAVD88 in meters.
    M: geoid separation measured in meters
    Defines that the seperation between GEIOD12A and the reference ellipsoid NAVD88 measured in meters(m). (Source: GrafNav) Indicates data is reported in meters.
    Age of differential GPS data record, Type 1 or Type 9. Null field when DGPS is not used.
    The corrected DGPS time (Source: GrafNav)
    Range of values
    Minimum:1
    Maximum:9
    Reference station ID, range 0000-4095. A null field when any reference station ID is selected and no corrections are received
    Refers to the reference station used to process the DGPS data presented in this dataset. (Source: GrafNav)
    Range of values
    Minimum:0
    Maximum:4095
    The checksum data, always begins with *
    The name of the checksum data used to detect errors. (Source: GrafNav) Numbers increase sequentially by 1.
    2014-322-FA_GPR Profile Images.zip
    File contains the Joint Photographic Experts Group (JPEG) images of the processed GPR profiles with the elevation corrections applied. For shore perpendicular profiles west is on the left hand side, east is on the right hand side. For shore-parallel north is on the left hand side south is on the right hand side. Data were exported from REFLEXW using a vertical velocity of 0.06 m/ns. (Source: USGS)
    2014-322-FA_GPR KML.zip
    File contains Keyhole Markup Language (KML) files of the GPR profiles. (Source: USGS)
    2014-322-FA_GPR KML.zip
    This file contains the spatial data associated with the GPR profiles in KML format, KML format can be viewed in google earth. (Source: Google earth) Spatial data.
    2014-322-FA_GPR profile parameters.xlsx
    Microsoft Excel table listing the parameters assigned to each GPR profile during collection in the field. (Source: USGS)
    Line
    Lists the profile name. (Source: User defined)
    Range of values
    Minimum:136
    Maximum:179
    scans/second
    The horizontal sampling rate if the system is in continous data collection mode. (Source: User defined) All lines were collected at a rate of 64 scans/second.
    scans/unit(m)
    Scan/unit(m) refers to the number of scans per horizontal meter. (Source: User defined) All lines were collected at a rate of 20 scans/unit.
    samples/scan
    Sample/scan set the number of data samples in a vertical scan. (Source: User defined) All lines were collected at a rate of 1024 samples/scan.
    bits/sample
    The bits/sample determine the dynamic range of the data. (Source: User defined) All lines were collected at 16 bits/sample.
    dielectric constant
    This column lists the assumed dielectric constant assigned to the GPR during collection of data, this determine the vertical scale in meters during data collection. (Source: User defined) Lines 136-147 and 152-179 were collected with a dielectric constant of 15, 148-151 were collected with a dielectric constant of 23.
    range(ns)
    range(ns) is the maximum two way travel time in nanoseconds that is viewed during data collection. (Source: User defined) Lines 136-147 were collected with a range of 200, Lines 148-151 were collected with a range of 100, lines 152-171 were collected with a range of 175 and lines 172-179 were collected with a range of 150.
    MHz
    The MHz of the antennae used to collect the data, 200 and 400 MHz antennaes were used. (Source: Defined by antennae used.) Lines 136-171 were collected with a 200 MHz antennae, lines 172-179 were collected with a 400 MHz antennae.
    2014-322-FA_FACs_Digital.zip
    Portable Document Format (PDF) files of the field logs, list of crew and equipment used during field activity 2014-322-FA. (Source: USGS)
    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 was 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)
    • Nicholas J. Zaremba
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Southeast Region
    Attn: Nicholas J. Zaremba
    Researcher IV
    600 4th Street South
    St. Petersburg, FL

    727-502-8000 (voice)
    727-502-8000 (FAX)
    nzaremba@usgs.gov

Why was the data set created?

This data series [AF2] consists of elevation corrected GPR profiles in Joint Photographic Experts Group (JPEG) format, raw GPR trace data and post-processed DGPS data in American Standard Code for Information Interchange (ASCII) format and Keyhole Markup Language (KML) data collected on Assateague Island. The data were collected as part of the Barrier Island Wetland Change Assessment (BIWC) (http://coastal.er.usgs.gov/sandy-wetland-assessment/). The primary goal of the BIWC project is to quantify the physical changes that storm processes have on barrier-island wetlands and marsh ecosystems.

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: 07-Jan-2015 (process 1 of 3)
    GPR processing: The GPR data were processed using Sandmeier Scientific Software’s Reflexw Version 7.2.2 geophysical near surface processing and interpretation software (http://www.sandmeier-geo.de/reflexw.html). Each GPR data file was imported into Reflex and converted from Radan’s proprietary DZT (.dzt) format to a .dat file. Next, a variety of processing steps were used including: applying static correction, subtracting-mean (dewow), removing header gain, and applying manual AGC gain. After these initial processing steps, the GPS and elevation data were integrated into the trace headers. Lastly, all profiles were inspected for data quality to ensure no navigation or trace data gaps were present before being output in ASCII format for the trace data (which can be downloaded at pubs.usgs.gov/ds/0989/downloads/2014-322-FA_GPR ASCII Raw Data.zip) and JPEG format for the profile images. If any issues were discovered during the QA/QC process, this information was noted for each affected line and recorded in the metadata. A velocity of 0.06 m/ns was used to calculate and display depth on the elevation-corrected profiles. 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
    Date: 26-Oct-2014 (process 2 of 3)
    Navigation processing: During acquisition, uncorrected real-time rover positions were output as a NMEA GGA string at a 9600 baud rate to an external GPS Acumen data logger [puck] and saved as a .plt file. A Matlab script written by C. Smith was used to extract the line name, time, latitude and longitude from each line's .plt file and this information was then saved as a CSV file. Person who carried out this activity:
    Julie Bernier
    U.S. Geological Survey
    Geologist
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
    jbernier@usgs.gov
    Date: 13-Oct-2020 (process 3 of 3)
    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?

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

  1. How well have the observations been checked?
    No formal attribute accuracy tests were conducted.
  2. How accurate are the geographic locations?
    Location information associated with each GPR line was determined by post-processed differential correction using a base/rover setup. Briefly, the field setup consisted of two (rover and base station) Ashtech ProFlex Global Navigation Satellite System (GNSS) receivers, collecting raw GNSS data, at 5 Hertz (Hz), Thales choke-ring antennas, tripods and data recorders.
  3. How accurate are the heights or depths?
    Location information associated with each GPR line was determined by post-processed differential correction using a base/rover setup. Briefly, the field setup consisted of two (rover and base station) Ashtech ProFlex Global Navigation Satellite System (GNSS) receivers, collecting raw GNSS data, at 5 Hertz (Hz), Thales choke-ring antennas, tripods and data recorders.
  4. Where are the gaps in the data? What is missing?
    A total of 44 GPR lines, representing a linear distance of approximately 10.5 kilometers, were acquired during field activity 2014-322-FA.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. Please see 'Distribution Information' for details.
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 dataset's metadata thoroughly to understand appropriate use and data limitations.
  1. Who distributes the data set? (Distributor 1 of 1)
    Nicholas J. Zaremba
    U.S. Geological Survey, Southeast Region
    Researcher IV
    600 4th Street South
    St. Petersburg, FL

    (727)-502-8000 (voice)
    nzaremba@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?

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
Nicholas J. Zaremba
U.S. Geological Survey, Southeast Region
Researcher IV
600 4th Street South
St.Petersburg, FL

727-502-8000 (voice)
727-502-8000 (FAX)
nzaremba@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/2014_322_FA_metadata.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:31 2021