Continuous Resistivity Profile Tracklines of Data Collected from Cape Cod National Seashore, May 17-20, 2004

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Frequently-anticipated questions:

What does this data set describe?

Title:
Continuous Resistivity Profile Tracklines of Data Collected from Cape Cod National Seashore, May 17-20, 2004
Abstract:
Continuous resistivity profiling (CRP) surveys were conducted at Cape Cod National Seashore in 2004 and 2006 in order to test hypotheses about groundwater flow under and into estuaries and the Atlantic Ocean. Coastal resource managers here and elsewhere are concerned about nutrients that are entering coastal waters via submarine groundwater discharge, which are contributing to eutrophication and harmful algal blooms. CRP is used to measure electrical resistivity of sediments, a property that is sensitive to differences in salinity of submarine ground water. The 2004 and 2006 surveys used floating resistivity streamers of 100 m and 50 m respectively. The depth penetration of the streamers is approximately 20% of the streamer length which translates to approximately 20-25 m with the 100 m streamer and 12-14 m with the 50 m streamer. These data were processed using AGI's EarthImager 2D software.
  1. How should this data set be cited?

    Bratton, John F. , 2008, Continuous Resistivity Profile Tracklines of Data Collected from Cape Cod National Seashore, May 17-20, 2004: Open-File Report 2006-1169, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Cross, VeeAnn A. , Bratton, John F. , Crusius, John, Colman, John A. , and McCobb, Timothy D. , 2008, Submarine Hydrogeological Data from Cape Cod National Seashore: Open-File Report 2006-1169, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.036200
    East_Bounding_Coordinate: -69.919617
    North_Bounding_Coordinate: 42.022050
    South_Bounding_Coordinate: 41.669400

  3. What does it look like?

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

    Beginning_Date: 17-May-2004
    Ending_Date: 20-May-2004
    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):

      • String (30)

    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 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    navproc_ln2004

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    ID
    Software generated identification number. (Source: Software.)

    Range of values
    Minimum:0
    Maximum:40

    LINENAME
    Prefix of the filename used during data acquisition. (Source: Technician.)

    character set

    TIME
    GPS time for the start of the trackline. (Source: Data processor.)

    Range of values
    Units:Time in hr:min:sec

    LENGTH
    Length in meters of the complete trackline based on UTM, Zone19, NAD83 projection. (Source: Software calculated.)

    Range of values
    Minimum:495.542
    Maximum:11474.6
    Units:meters

    COLDATE
    Date of data acquisition. (Source: Data processor.)

    character set

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    John F. Bratton
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    508-548-8700 x2254 (voice)
    508-457-2210 (FAX)
    jbratton@usgs.gov

Why was the data set created?

This shapefile is provided to show the tracklines where continuous resistivity profile data were collected and processed.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Source_Contribution:
    These data were acquired with an AGI SuperSting Marine system that is described at the website: www.agiusa.com/marinesystem.shtml. The particular system used for this acquisition was an 11 stainless steel electrode array with electrodes spaced 10 meters apart. A dipole-dipole configuration was used for the data collection in which two fixed current electrodes are assigned with the measurement of voltage potentials between electrode pairs in the remaining electrodes. Each line of data acquisition records several files. The two files necessary for processing are the *.stg and *.gps file. The STG file contains the resistivity data, while the GPS file contains the navigation information. Bathymetry point data was collected with a separate system and logged as text files.

  2. How were the data generated, processed, and modified?

    Date: 2004 (process 1 of 8)
    The data were transferred from the logging computer via AGISSAdmin software.

    Person who carried out this activity:

    John F. Bratton
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2254 (voice)
    (508) 457-2310 (FAX)
    jbratton@usgs.gov

    Date: 2004 (process 2 of 8)
    The bathymetry text files needed to be merged with the GPS navigation files. The logging of the navigation files started at the same time as the logging of the resistivity files. Although the bathymetry data contains no time stamps, the assumption was made that the time span was the same as the navigation file. The bathymetry data was acquired in feet at a faster rate than the navigation data. An awk script was written to convert the bathymetry data to meters, pull the appropriate bathymetry point to match up with the navigation point, and output the format as SDDBT (the format that EarthImager expects). The points to pull was based on the assumption that the time span of navigation and bathymetry was the same, so took the total number of bathymetry points and divided it by the number of navigational fixes, and pulled the bathymetry point at that increment. Another awk script was written to merge the navigation data and bathymetry data into a single file.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Date: 2004 (process 3 of 8)
    $GPRMC lines with the GPS file that had bad time stamps or were otherwise corrupt were deleted.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Date: 2004 (process 4 of 8)
    The GPS files were processed using an AWK script to parse out the navigational and bathymetric information from the $GPRMC and $SDDPT strings and concatenate this information into a single file.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Date: 2004 (process 5 of 8)
    This comma delimited text file was then imported as a table into ArcView 3.3.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Date: 2004 (process 6 of 8)
    The table was then added as an event theme into ArcView.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Date: 2004 (process 7 of 8)
    An avenue script (pnts2lines.ave) was run that converted the event theme to a polyline shapefile. The unique attribute "Linename" was used to generate a separate record for each individual acquisition line.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Date: 2004 (process 8 of 8)
    Lines for which there was no valid resistivity data were deleted.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (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?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

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

    Only those lines with valid resistivity data are represented here.

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

    No additional checks for topological consistency other than visual inspection were performed on the data.

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:
The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data.

  1. Who distributes the data set? (Distributor 1 of 1)

    John F. Bratton
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2254 (voice)
    (508) 457-2310 (FAX)
    jbratton@usgs.gov

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    These data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.

Who wrote the metadata?

Dates:
Last modified: 25-Feb-2008
Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)
vatnipp@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.6 on Tue Jul 08 11:23:20 2008