Trimmed Processed Continuous Resistivity Point Data from Cape Cod National Seashore, May 17-20, 2004

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Frequently anticipated questions:


What does this data set describe?

Title:
Trimmed Processed Continuous Resistivity Point Data 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 might this data set be cited?
    Bratton, John F., 2008, Trimmed Processed Continuous Resistivity Point Data 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 Coastal and Marine 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, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.036194
    East_Bounding_Coordinate: -69.919618
    North_Bounding_Coordinate: 42.022037
    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):
      • Entity point (1323510)
    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 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.
  7. How does the data set describe geographic features?
    mrg2004_trimxyz
    Information unavailable from original metadata. (Source: Information unavailable from original metadata.)
    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:1
    Maximum:129926
    DIST
    Distance along line (in meters) that the data point occurs. (Source: Processing software calculated.)
    Range of values
    Minimum:0.1
    Maximum:11471.5
    DEPTH
    Depth from water surface (in meters) where the data point occurs. (Negative value indicates below the water surface) (Source: Processing software generated.)
    Range of values
    Minimum:-28.060
    Maximum:-0.3900
    Units:meters
    RESVALUE
    Resistivity value of the data point. (Source: Processing software calculated.)
    Range of values
    Minimum:0.1
    Maximum:1000
    Units:ohm-meters
    LONGITUDE
    Longitude position of the data point. (Source: Software calculated.)
    Range of values
    Minimum:-70.036194
    Maximum:-69.919618
    Units:decimal degrees
    LATITUDE
    Latitude position of the data point. (Source: Software calculated.)
    Range of values
    Minimum:41.669400
    Maximum:42.022037
    Units:decimal degrees
    UTMX
    UTM easting, based on UTM Zone 19, position of the data point. (Source: Software calculated.)
    Range of values
    Minimum:414214.0
    Maximum:423458.5
    Units:meters
    UTMY
    UTM northing, based on UTM Zone 19, position of the data point. (Source: Software calculated.)
    Range of values
    Minimum:4613497.9
    Maximum:4652742.3
    Units:meters
    LINE
    Resistivity data collection line where the data point is from. (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)
    • John F. Bratton
  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

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

Why was the data set created?

To provide processed resistivity data as a point shapefile. This version has removed all the data points that fall above the sediment/water interface.

How was the data set created?

  1. From what previous works were the data drawn?
    Raw data (source 1 of 1)
    USGS, unpublished material, Raw CRP data.

    Other_Citation_Details:
    This file had a source contribution, but no source citation information. This information was populated based on information in the source contribution.
    Type_of_Source_Media: digital data
    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 14)
    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

    (508) 548-8700 x2254 (voice)
    (508) 457-2310 (FAX)
    jbratton@usgs.gov
    Date: 2004 (process 2 of 14)
    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

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 3 of 14)
    $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

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 4 of 14)
    The resistivity data were merged with the navigation data and linearized using AGI's Marine Log Manager software. (Note that the Marine Log Manager version is different than the software version of the AGISSAdmin software of which it is a part - although shipped together, the software is developed separately). In some instances, only a portion of the line was exported for processing. In particular, turns are removed before processing. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 5 of 14)
    The file was then exported to a new STG file, and accompanying DEP file. The DEP file contains the distance along line and bathymetry values. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 6 of 14)
    The DEP file was checked for anomalous bathymetry values, or duplicated distance along values, and those lines in the file were deleted. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 7 of 14)
    EarthImager software does not require that a default resistivity value for the water column be supplied in the DEP file. If one is not supplied, then it calculates a value based on the first electrode pair. No instrument was available to measure the water resistivity, so this value was left blank. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 8 of 14)
    EarthImager version 1.7.8 was used to process the data files. The *.ini file accompanying the results contains the parameters used during the processing. These parameters include: minimum voltage: 0.02; minimum abs(V/I): 2E-5; max repeat error: 3%; min apparent res: 0.03; max apparent res: 1000; max reciprocal error: 5%; remove spikes, robust model inversion; finite difference method; Cholesky decomposition; Dirichlet boundary condition; thickness incremental factor: 1.1; depth factor: 1.1; number of iterations: 8; stop criteria: max RMS 3%; error reduction 6%; L2Norm; CRP processing using a 65% overlap Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 9 of 14)
    The results of the processing are JPEG images of the resistivity profile (a short and extended version), and an XYZ file containing the distance along, depth, apparent resistivity (ohm-m). The JPEG files produced use a color scale that is based on the data from that particular file. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 10 of 14)
    The XYZ output file was loaded into Matlab with the DEP file so that those resistivity values in the water column could be removed. The extrapolated value at the sediment water interface was exported, as well as all the values in the original XYZ file below the DEP line. These new XYZ files are the "trimmed" xyz files. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 11 of 14)
    An ArcView 3.3 avenue script (createatdistance.ave) was used to read the trimmed XYZ files, and based on the distance along value, extract the geographic X and Y position based on the polyline trackline. The result is a point shapefile containing each line of information in the XYZ file. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2004 (process 12 of 14)
    Each individual trimmed XYZ shapefile was merged into a single point shapefile. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 09-Nov-2015 (process 13 of 14)
    Edits to the metadata were made to fix any errors that MP v 2.9.30 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. The source citation information is inferred from other information in the metadata and was not part of the original metadata file. Source time period of content was inferred from the time period of the dataset. Needed to add link to data in the distribution section. Other minor edits were probably performed (title, publisher, publication place, etc.). The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 14 of 14)
    USGS Thesaurus keywords added to the keyword section. 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?
  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

    (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: 20-Jul-2018
Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA

(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)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/eastcoast/gome/capecod/mrg2004_trimxyz.shp.faq.html>
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