RESGPSPNTS_JD135.SHP: Navigation and Bathymetry Points of Ship Position During Continuous Resistivity Profile Data Collection in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005

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Frequently-anticipated questions:


What does this data set describe?

Title:
RESGPSPNTS_JD135.SHP: Navigation and Bathymetry Points of Ship Position During Continuous Resistivity Profile Data Collection in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005
Abstract:
Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient delivery to Chesapeake Bay via this pathway. Resource managers are concerned about nutrients that are entering the estuary via submarine groundwater discharge from this primarily agricultural watershed that may be contributing to eutrophication, harmful algal blooms, and fish kills. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the estuary in April and May 2007. Techniques used included continuous resistivity profiling (CRP), piezometer sampling, seepage meter measurements, and collection of a radon tracer time series. Better understanding of the style, locations, and rates of groundwater discharge could lead to improved models and mitigation strategies for estuarine nutrient over-enrichment in the Corsica River Estuary, and other similar settings. More information on the field work can be accessed from the Woods Hole Coastal and Marine Science Center Field Activity webpage: <http://quashnet.er.usgs.gov/data/2007/07005/>
  1. How should this data set be cited?

    Bratton, John F. , and Cross, VeeAnn A. , 2011, RESGPSPNTS_JD135.SHP: Navigation and Bathymetry Points of Ship Position During Continuous Resistivity Profile Data Collection in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005: Open-File Report 2010-1094, 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. , Worley, Charles R. , Crusius, John, and Kroeger, Kevin D. , 2011, Continuous resistivity profiling data from the Corsica River Estuary, Maryland: Open-File Report 2010-1094, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -76.126683
    East_Bounding_Coordinate: -76.106167
    North_Bounding_Coordinate: 39.090933
    South_Bounding_Coordinate: 39.072400

  3. What does it look like?

    <https://pubs.usgs.gov/of/2010/1094/data/navigation/resgpspnts_jd135.gif> (GIF)
    Thumbnail image showing the location of resistivity navigation points collected May 15, 2007. The coastline is included for spatial reference.

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

    Calendar_Date: 15-May-2007
    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 (2235)

    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 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.

      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    resgpspnts_jd135
    ESRI point shapefile (Source: ESRI)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    gpstime
    GPS time in the format HHMMSS. GPS time is +4 from local time during the survey. (Source: U.S. Geological Survey)

    Although the value is represented as a number, the number as a whole doesn't have a particular meaning. Only when the individual parts for hours, minutes, and seconds are broken out does the number have meaning.

    longitude
    Longitude coordinate of the point in decimal degrees, NAD83. (Source: U.S. Geological Survey)

    Range of values
    Minimum:-76.126683
    Maximum:-76.106167
    Units:decimal degrees

    latitude
    Latitude coordinate of the point in decimal degrees, NAD83. (Source: U.S. Geological Survey)

    Range of values
    Minimum:39.0724
    Maximum:39.090933
    Units:decimal degrees

    depth_m
    Depth of the water below the fathometer in meters recorded by the ship's fathometer/navigation system. Datum is local surface (no tides taken into account). A value of -9999 indicates no data. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.3
    Maximum:4.6
    Units:meters

    temp_c
    Water temperature in degrees Celsius as recorded at the Lowrance fathometer transducer. A value of -9999 indicated no data. (Source: U.S. Geological Survey)

    Range of values
    Minimum:20
    Maximum:24.2
    Units:degrees Celsius

    line
    The alphanumeric name corresponding to the prefix of the GPS filename. This name reflects the name assigned to the line of data acquisition and incorporates modifiers to reflect modification of the GPS file if the GPS file was split into more than one part. (Source: U.S. Geological Survey)

    Character set.

    jday
    This number represents the Julian day of data collection based on the GPS day. Julian day is the integer number representing the interval of time in days since January 1 of the year. (Source: U.S. Geological Survey)

    Range of values
    Minimum:135
    Maximum:135
    Units:days

    gpsdate
    The date recorded in the GPS navigation in the format DDMMYY. Because of the time offset from local time, this date could actually be different than the local acquisition date. (Source: U.S. Geological Survey)

    Character set.

    gps_src
    The system from which the navigation point was derived. (Source: U.S. Geological Survey)

    Character set.

    bathy_src
    The system from which the bathymetric value was acquired. (Source: U.S. Geological Survey)

    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
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

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

    Contact_Instructions:
    Current address: NOAA/GLERL 4840 S. State Rd. Ann Arbor MI 48108-9719 734-741-2235 John.Bratton@noaa.gov


Why was the data set created?

The purpose of this point shapefile is to provide the ship's position and bathymetric values (when available) during the collection of continuous resistivity profile data in the Corsica River Estuary, Maryland on May 15, 2007.


How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Source_Contribution:
    The continuous resistivity profile (CRP) system used on this cruise was an AGI SuperSting marine system described at the website: www.agiusa.com/marinesystem.shtml. The particular system used for this acquisition was a 50-m streamer with an 11 electrode array with electrodes spaced 5 meters apart. The source electrodes are graphite, while the receiver electrodes are 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 potential between electrode pairs in the remaining electrodes. The maximum depth below the water surface the streamer can reach is approximately the streamer length. So for the 50-m streamer, maximum depth is about 12.5 meters. Each line of data acquisition records several files. The two files necessary for processing are the *.stg and the *.gps file. The STG file contains the resistivity data, while the GPS file contains the navigation information. The navigation system used in concert with the CRP system is a Lowrance LMS-480M with an LGC-2000 GPS antenna and a 200 kHz fathometer transducer. The transducer also contains a temperature sensor. Lowrance indicates the speed of sound used by the system is 4800 feet/second. Both the temperature and depth information are recorded in the logged GPS file. There are instances where no depth or temperature information is recorded due to an equipment problem. The CRP system images the subsurface electrical properties of an estuarine, riverine or lacustrine environment. Resistivity differences can be attributed to subsurface geology (conductive vs less conductive layers) and hydrogeologic conditions with fresh water exhibiting high resistivity and saline conditions showing low resistivity.

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

    Date: 2007 (process 1 of 7)
    The data were transferred from the logging computer via AGISSAdmin software version 1.3.2.165. The data files available for this day are L1F1*, L2F1*, L3F1*, L4F1*, F5L1*, L6F1*, L7F1*, L8F1*, L9F1*, L9F2*, L10F1*, L11F1*, L12F1*, L12F2*, L13F1*. These files were then transferred via a thumb drive to the processing computer. The files included in this publication are the *.crs, *.cmd, *.gps, and *.stg. The two files essential for processing are the GPS and STG files. The GPS file contains the navigation, and in the case of the Lowrance system also includes water depth and temperature. The STG file contains the resistivity measurements from each of the electrodes. The CRS file contains the contact resistance readings. The CMD file contains the parameters for data collection. These last two files aren't necessary for data processing, but can be useful in terms of troubleshooting. This process step, along with all subsequent process steps, was performed by the same person: VeeAnn A. Cross

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

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

    Date: 2007 (process 2 of 7)
    An AWK script was used to extract the navigation, Bathymetry, and temperature information recorded in each individual GPS data file. (* refers to the line name, which for this day are L1F1, L2F1, L3F1, L4F1, F5L1, L6F1, L7F1, L8F1, L9F1, L9F2, L10F1, L11F1, L12F1, L12F2, L13F1.)
    AWK script "awkgps":
    BEGIN {
    FS = ","
    }
    {
    FS = ","
    ARGC = 2
    depth = -9999
    temp = -9999
    if ($1=="$GPRMC")
    	{
    	utctime = $2
    	latdeg = substr($4,1,2)
    	latmin = substr($4,3,6)
    	declat = latdeg + (latmin/60)
    	londeg = substr($6,1,3)
    	lonmin = substr($6,4,6)
    	declon = -1 * (londeg + (lonmin/60))
    	holddepth = -9999
    	}
    if ($1=="$SDDPT")
    	{
    	depthreal = $2
    	holddepth = depthreal
    	}
    if ($1=="$SDMTW")
    	{
    	temp = $2
    	if (holddepth > -1) {
    		printf("%s, %9.6f, %9.6f, %3.1f, %4.1f, %s\n", utctime, declon, declat, holddepth, temp, ARGV[2])
    	}
    	else {
    		printf("%s, %9.6f, %9.6f, %3.1f, %4.1f, %s\n", utctime, declon, declat, depth, temp, ARGV[2])
    	}
    	holddepth = -9999
    	}
    }
    
    This AWK script was initialized by "doawk" - shell script run under CYGWIN (UNIX like environment that runs under Windows):
    files=`ls *.gps | cut -d. -f1 | tr "[A-Z"] ["a-z"]`
    for file in $files
    do
    	awk -f awkgps $file.gps $file > $file.txt
    done
    

    Data sources used in this process:

    • *.gps

    Data sources produced in this process:

    • *.txt

    Date: 2007 (process 3 of 7)
    These files were then appended to each other using the UNIX cat command. cat l1f1.txt l2f1.txt l3f1.txt l4f1.txt f5l1.txt l6f1.txt l7f1.txt l8f1.txt l9f1.txt l9f2.txt l10f1.txt l11f1.txt l12f1.txt l12f2.txt l13f1.txt > day1gps.txt

    Data sources used in this process:

    • *.txt

    Data sources produced in this process:

    • day1gps.txt

    Date: 2007 (process 4 of 7)
    VI under CYGWIN was used to add the appropriate header line and the comma-delimited text file was imported to ArcMap 9.1: Tools - Add XY Data. The X field is longitude; Y field is latitude, and the Coordinate System was defined as Geographic, NAD83. This "Event Theme" was converted to a shapefile by right-mouse clicking on the layer - Data - Export Data. The output was saved as day1gps.shp

    Data sources used in this process:

    • day1gps.txt

    Data sources produced in this process:

    • day1gps.shp

    Date: 2007 (process 5 of 7)
    Visual inspection of the shapefile indicated that there was one bad fix. Prior to editing the shapefile, the file was copied to day1gpsclean.shp by right-mouse clicking on the layer - Data - Export Data and saving the output to day1gpsclean.shp. Within an edit session, the bad record was selected with in the shapefile table and deleted.

    Data sources used in this process:

    • day1gps.shp

    Data sources produced in this process:

    • day1gpsclean.shp

    Date: Nov-2009 (process 6 of 7)
    Within ArcCatalog 9.2 the "clean" shapefile was copied to a new file with the name resgpspnts_jd135.shp.

    Data sources used in this process:

    • day1gpsclean.shp

    Data sources produced in this process:

    • resgpspnts_jd135.shp

    Date: Nov-2009 (process 7 of 7)
    Using ArcMap 9.2 added the attributes "gps_src' and "bathy_src" to be consistent with previously published data in cases where other sources were used for navigation and/or bathymetry.

    Data sources used in this process:

    • resgpspnts_jd135.shp

    Data sources produced in this process:

    • resgpspnts_jd135.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?

    The navigation system used was a Lowrance 480M with an LGC-2000 Global Positioning System (GPS) antenna. The antenna was located at the anchor point for the resistivity streamer, which is also directly above the fathometer transducer mount point. The GPS system is published to be accurate to within 10 meters.

  3. How accurate are the heights or depths?

    All collected bathymetry values were collected by the 200 kHz Lowrance fathometer. The fathometer was mounted starboard side aft, directly below the GPS antenna and the resistivity streamer tow point. The Lowrance manufacturer indicates the speed of sound used by the system to convert to depths is 4800 feet/second. All values are assumed to be accurate to within 1 meter.

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

    All available navigation, bathymetry and temperature information available on this day is included in the dataset. Files L12F1, L12F2 and L13F1 did not have bathymetry values in the navigation files.

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

    No duplicate points are present. The navigational fixes were checked for valid values. Invalid data points were deleted. No other checks were performed.


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 public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.

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

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@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?

    This WinZip file contains data available in ESRI point shapefile format. The user must have software capable of uncompressing the WinZip file and reading/displaying the shapefile.


Who wrote the metadata?

Dates:
Last modified: 14-Jan-2011
Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
Woods Hole Coastal and Marine Science Center
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 2.9.6 on Fri Jan 14 14:16:22 2011