Extended Tracklines of Continues Resistivity Profile Data collected in 2005 in the Neuse River, North Carolina

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Frequently-anticipated questions:

What does this data set describe?

Title:
Extended Tracklines of Continues Resistivity Profile Data collected in 2005 in the Neuse River, North Carolina
Abstract:
The Neuse River Estuary in North Carolina is a broad, V-shaped water body located on the southwestern end of Pamlico Sound. This estuary suffers from severe eutrophication for which several water quality models have recently been developed to aid in the management of nutrient loading to the estuary. In an effort to help constrain model estimates of the fraction of nutrients delivered by direct ground-water discharge, continuous resistivity profile (CRP) measurements were made during the spring of 2004 and 2005. CRP is used to measure electrical resistivity of sediments, a property that is sensitive to difference in salinity of submarine ground water. The 2004 and 2005 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. CRP data enables the mapping of the extent and depth of the fresher ground water within the estuary.
  1. How should this data set be cited?

    Cross, VeeAnn A. , 2005, Extended Tracklines of Continues Resistivity Profile Data collected in 2005 in the Neuse River, North Carolina:.

    Online Links:

    This is part of the following larger work.

    Cross, VeeAnn A. , Bratton, John F. , Bergeron, Emile, Meunier, Jeff K. , Crusius, John, and Koopmans, Dirk, 2005, Continuous Resistivity Profiling Data from the Upper Neuse River Estuary, North Carolina, 2004-2005: Open-File Report 2005-1306, 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: -76.980495
    East_Bounding_Coordinate: -76.840531
    North_Bounding_Coordinate: 35.019317
    South_Bounding_Coordinate: 34.937251

  3. What does it look like?

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

    Beginning_Date: 04-May-2005
    Ending_Date: 05-May-2005
    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 (4)

    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?

    extendedlines_05

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    ID
    Unique number identifying each polyline. (Source: Computer generated.)

    Range of values
    Minimum:1
    Maximum:9

    LINENAME
    String representing the prefix of the original resistivity line name. (Source: Data processor.)

    character set

    COL_TIME
    The time at which data collection began, UTC time. (Source: Software.)

    time in hr:min:sec

    COL_DATE
    Date of data acquisition. (Source: Software.)

    date in the format of DDMMYR

    EXTENDED
    The distance in meters that the line was extended. (Source: Data processor.)

    Range of values
    Minimum:21.7
    Maximum:32.5
    Units:meters

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?

Why was the data set created?

To provide extended tracklines for the lines where the resistivity streamer was towed from shore.

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 electrode array with electrodes spaced 5 meters apart. The potential electrodes are made of graphite, with the remaining electrodes stainless steel. 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.

    Several tracklines were initiated with the resistivity streamer onshore and pulled away perpendicular to the beach. Because the streamer is behind the boat, any resistivity values acquired prior to crossing the boat's initial position are recorded as negative distances along line. In order to geographically place these readings, the tracklines needed to be extended shoreward.

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

    (process 1 of 3)
    Four tracklines were started with the streamer on the shore. These were lines 3, 4, 5, and 9. I extracted the individual tracklines from the composite polyline shapefile.

    Data sources used in this process:

    • restracklines_05.shp

    Data sources produced in this process:

    • l3f1_4extend.shp
    • l4f1_4extend.shp
    • l5f1_4extend.shp
    • l9f1_4extend.shp

    (process 2 of 3)
    A sample avenue script was downloaded from ESRI's Knowledge base and was modified so that a shapefile polyline could be extended by a user entered amount. The direction of the extension was from the beginning of the line in a direction consistent with the angle of the beginning of the line. The length of the extension was determined from the processed resistivity data in which all the data were included. The first negative value in the resulting XYZ file was used as the length of the extension (entered as a positive value).

    (process 3 of 3)
    The geoprocessing extension in ArcView 3.3 was used to merge the individual shapefiles into a single shapefile.

    Data sources produced in this process:

    • extendedlines_05.shp

  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?

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

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 contact information not provided.]

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

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    These data were prepared by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Although all data published in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 01-Nov-2005
Metadata author:
REQUIRED: The organization responsible for the metadata information.
c/o REQUIRED: The person responsible for the metadata information.
REQUIRED: The city of the address., REQUIRED: The state or province of the address. REQUIRED: The ZIP or other postal code of the address.

REQUIRED: The telephone number by which individuals can speak to the organization or individual. (voice)

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 Nov 01 14:50:29 2005