YSI_MERGE.SHP: Point shapefile containing valid YSI 600 XLM multi-parameter sonde data (temperature, conductivity, and salinity) in Indian River Bay, Delaware, collected on U.S. Geological Survey Field Activity 2010-006-FA in April 2010 (Geographic, WGS 84)

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Frequently-anticipated questions:

What does this data set describe?

Title:
YSI_MERGE.SHP: Point shapefile containing valid YSI 600 XLM multi-parameter sonde data (temperature, conductivity, and salinity) in Indian River Bay, Delaware, collected on U.S. Geological Survey Field Activity 2010-006-FA in April 2010 (Geographic, WGS 84)
Abstract:
A geophysical survey to delineate the fresh-saline groundwater interface and associated sub-bottom sedimentary structures beneath Indian River Bay, Delaware, was carried out in April 2010. This included surveying at higher spatial resolution in the vicinity of a study site at Holts Landing, where intensive onshore and offshore studies were subsequently completed. The total length of continuous resistivity profiling (CRP) survey lines was 145 kilometers (km), with 36 km of chirp seismic lines surveyed around the perimeter of the bay. Medium-resolution CRP surveying was performed using a 50-meter streamer in a bay-wide grid. Results of the surveying and data inversion showed the presence of many buried paleochannels beneath Indian River Bay that generally extended perpendicular from the shoreline in areas of modern tributaries, tidal creeks, and marshes. An especially wide and deep paleochannel system was imaged in the southeastern part of the bay near White Creek. Many paleochannels also had high-resistivity anomalies corresponding to low-salinity groundwater plumes associated with them, likely due to the presence of fine-grained estuarine mud and peats in the channel fills that act as submarine confining units. Where present, these units allow plumes of low-salinity groundwater that was recharged onshore to move beyond the shoreline, creating a complex fresh-saline groundwater interface in the subsurface. The properties of this interface are important considerations in construction of accurate coastal groundwater flow models. These models are required to help predict how nutrient-rich groundwater, recharged in agricultural watersheds such as this one, makes its way into coastal bays and impacts surface water quality and estuarine ecosystems. For more information on the survey conducted for this project, see <http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2010-006-FA>.
  1. How should this data set be cited?

    Bratton, John F. , and Green, Adrian, 2014, YSI_MERGE.SHP: Point shapefile containing valid YSI 600 XLM multi-parameter sonde data (temperature, conductivity, and salinity) in Indian River Bay, Delaware, collected on U.S. Geological Survey Field Activity 2010-006-FA in April 2010 (Geographic, WGS 84): Open-File Report 2011-1039, 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, V.A., Bratton, J.F., Michael, H.A., Kroeger, K.D., Green, A., and Bergeron, E., 2014, Continuous Resistivity Profiling and Seismic-Reflection Data Collected in April 2010 from Indian River Bay, Delaware: Open-File Report 2011-1039, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -75.203217
    East_Bounding_Coordinate: -75.063050
    North_Bounding_Coordinate: 38.619333
    South_Bounding_Coordinate: 38.566450

  3. What does it look like?

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

    Beginning_Date: 13-Apr-2010
    Ending_Date: 15-Apr-2010
    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 (672)

    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 D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.

  7. How does the data set describe geographic features?

    ysi_Merge
    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.

    ysi_date
    The date the YSI data were collected in the format M/DD/YYYY (Source: Data processor.)

    Characters set.

    ysi_time
    The time the YSI data point was logged in local time in the format HH:MM:SS. (Source: Data processor.)

    Characters set.

    utc_time
    The UTC time corresponding to the acquisition of the YSI point in the format HH:MM:SS. (Source: Data processor.)

    Characters set.

    temp_c
    Water temperature value in degrees Celsius recorded by the YSI sensor. (Source: Data processor.)

    Range of values
    Minimum:9.76
    Maximum:19.78
    Units:degrees Celsius

    mspcm
    Water conductivity measured by the YSI sensor in milli-Seiemens per centimeter. (Source: Data processor.)

    Range of values
    Minimum:18.08
    Maximum:36.08
    Units:milli-Siemens per centimeter

    sal_ppt
    Water salinity measured by the YSI sensor in parts per thousand. (Source: Data processor.)

    Range of values
    Minimum:12.62
    Maximum:27.63
    Units:parts per thousand

    comments
    Comments added to the original Excel spreadsheet. (Source: Data processor.)

    Characters set.

    longitude
    Longitude coordinate of the point (WGS84). (Source: Data processor.)

    Range of values
    Minimum:-75.203217
    Maximum:-75.06305
    Units:decimal degrees

    latitude
    Latitude coordinate of the point (WGS84). (Source: Data processor.)

    Range of values
    Minimum:38.56645
    Maximum:38.619333
    Units:decimal degrees

    Resval
    Calculated resistivity value of the point. (Source: Software generated.)

    Range of values
    Minimum:0.2771
    Maximum:0.5528
    Units:ohm-m

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?

    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

Why was the data set created?

This point shapefile provides geographic locations and sensor data from the YSI 600 XLM multi-parameter sonde that have been determined to be valid. The YSI sensor measures temperature, conductivity, and salinity.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Source_Contribution:
    The YSI 600XLM was mounted just behind the fathometer transducer on the starboard side of the boat. This placed the instrument almost directly below the navigation antenna. On the first three days of data collection (April 12-14) this mount location was 17.6 m forward of the first electrode in the continuous resistivity profiling streamer array. On the fourth day (April 15), the GPS/YSI package was moved 1.6 meters toward the stern. Although data collection was continuous, recording a reading every minute, the values are fairly inconsistent. This inconsistency is possibly due to the YSI cavitating at speed, or too much air in the sensor cavity from fast moving water.

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

    Date: May-2010 (process 1 of 7)
    First, the raw YSI data were separated by day of acquisition into separate worksheets in Microsoft Excel 2003. Then a new column was added to reflect UTC time by adding 4 hours to the YSI time (local time). 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: Jun-2010 (process 2 of 7)
    The GPS HYPACK navigation for each day of data collection is already in a comma-delimited text file from other processing (see metadata for the various jd***bestdepth shapefiles available at <http://pubs.usgs.gov/of/2011/1039/html/ofr2011-1039-catalog.html>). These files simply need to be reformatted for use with the YSI data so that the Excel command VLOOKUP can be used with the lookup column being time. The idea is to carry over the latitude and longitude values from the GPS file when the YSI time is the same as the GPS time. HYPACK software usually recorded a navigation fix every second. There were times when HYPACK was off, and that will be discussed later. VLOOKUP has two methods of operation: one when the match is exact, and the other is approximate match. For some reason, using the exact match did not work well. Times that were exact matches still produced NA values. Therefore, the approximate match method was used. The approximate match method find the largest value less than or equal to the match value. Manual editing was done in Excel to remove the latitude longitude values that carried over from HYPACK navigation gaps.

    Date: Jun-2010 (process 3 of 7)
    Once the VLOOKUP and editing were complete, the values were copied to a new worksheet to be exported from Excel. In order to determine valid YSI values, John Bratton wanted to not only look at the values in the spreadsheet, but also look at the spatial distribution of the data point and their values. The worksheet was exported from Excel as a comma-delimited text file and added to ArcMap 9.2 as an event theme by Tools - AddXY data, projection as geographic, WGS84. The event theme was then converted to a shapefile by right mouse click - data - export. A shapefile for each day of data collection was generated.

    Data sources produced in this process:

    • apr13_ysi_withnav.shp
    • apr14_ysi_withnav.shp
    • apr15_ysi_withnav.shp

    Date: Jul-2010 (process 4 of 7)
    Based on the spatial distribution of the YSI data values, and visual inspection of the data files in the Excel spreadsheet, John Bratton made a final worksheet containing the YSI values he considered valid. Once these values were selected, new shapefiles were generated containing only the accepted YSI values. This meant a repeat of the VLOOKUP procedures marrying the HYPACK navigation fixes with the valid YSI values, export from Excel, added as an event theme to ArcMap, and then exported as a shapefile for April 13, 14, and 15.

    Data sources used in this process:

    • apr13_ysi_withnav.shp
    • apr14_ysi_withnav.shp
    • apr15_ysi_withnav.shp
    • Excel spreadsheet

    Data sources produced in this process:

    • cull_4_13_exp.shp
    • cull_4_14_exp.shp
    • cull_4_15_exp.shp

    Date: Jul-2010 (process 5 of 7)
    The filtered (culled) YSI shapefiles do not have the measurements in the units I need. So within ArcMap 9.2, using VAC Extras, version 2.1 (an extension written by VeeAnn Cross in Woods Hole), the resistivity values in ohm-m were calculated. VACExtras - Resistivity - Calc Resistivity. The calculation requires a temperature field in degrees Celsius and a salinity field - both of which are present in the YSI culled shapefile. The results are put in a new attribute called resval.

    Data sources used in this process:

    • cull_4_13_exp.shp
    • cull_4_14_exp.shp
    • cull_4_15_exp.shp

    Data sources produced in this process:

    • cull_4_13_exp.shp
    • cull_4_14_exp.shp
    • cull_4_15_exp.shp

    Date: Jun-2011 (process 6 of 7)
    In ArcMap 9.2 outlier points (those YSI points with locations plotting outside the study are) were deleted. These outliers were a result of no corresponding GPS coordinates, leading to latitude and longitude values of 0. The shapefiles were renamed to reflect these edits.

    Data sources used in this process:

    • cull_4_13_exp.shp
    • cull_4_14_exp.shp
    • cull_4_15_exp.shp

    Data sources produced in this process:

    • ysi_4_13_cln.shp
    • ysi_4_14_cln.shp
    • ysi_4_15_cln.shp

    Date: Jun-2011 (process 7 of 7)
    In ArcMap 9.2 the individual YSI shapefiles were merged into a single shapefile using ArcToolbox - Data Management Tools - General -Merge. Because the individual shapefiles all have the same attributes, nothing needed to be done to the field mapping. The output shapefile was ysi_Merge.shp.

    Data sources used in this process:

    • ysi_4_13_cln.shp
    • ysi_4_14_cln.shp
    • ysi_4_15_cln.shp

    Data sources produced in this process:

    • ysi_Merge.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 directly above the fathometer transducer mount point, but offset to the starboard by 2 meters from the resistivity streamer tow point. The YSI meter was mounted just behind the fathometer. GPS data are assumed to be accurate within 10 meters on this survey.

  3. How accurate are the heights or depths?

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

    All YSI values deemed to be valid that have associated navigation fixes from April 13, 2010 are contained in this data file.

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

    A selection process was performed by two USGS scientist to determine the valid data values acquired by the sensor. This selection process was largely subjective.

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

Who wrote the metadata?

Dates:
Last modified: 30-Jun-2014
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 Mon Jun 30 16:35:45 2014