IR_ROUTES_CALIB.SHP: Shot-point calibrated trackline navigation for chirp seismic data collected in Indian River Bay, Delaware, on April 13, 2010, on U.S. Geological Survey Field Activity 2010-006-FA (Geographic, WGS 84)

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Frequently-anticipated questions:

What does this data set describe?

Title:
IR_ROUTES_CALIB.SHP: Shot-point calibrated trackline navigation for chirp seismic data collected in Indian River Bay, Delaware, on April 13, 2010, on U.S. Geological Survey Field Activity 2010-006-FA (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 Cross, VeeAnn A. , 2014, IR_ROUTES_CALIB.SHP: Shot-point calibrated trackline navigation for chirp seismic data collected in Indian River Bay, Delaware, on April 13, 2010, on U.S. Geological Survey Field Activity 2010-006-FA (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: -75.202086
    East_Bounding_Coordinate: -75.062936
    North_Bounding_Coordinate: 38.618986
    South_Bounding_Coordinate: 38.569244

  3. What does it look like?

    <http://pubs.usgs.gov/of/2011/1039/data/navigation/seismics/ir_Routes_Calib.gif> (GIF)
    Thumbnail GIF image showing the location of seismic tracklines in Indian River Bay. The coastline is included for spatial reference.

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

    Calendar_Date: 13-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):

      • String (16)

    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?

    ir_Routes_Calib
    ESRI polyline 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.

    linename
    The unique identifier for each line of data acquistion. This is the prefix of the SEG-Y filename. (Source: U.S. Geological Survey)

    Character set.

    shot
    The shot number associated with the start of the line. (Source: U.S. Geological Survey)

    Range of values
    Minimum:1
    Maximum:1
    Units:shot

    year
    Calendar year of data collection. (Source: U.S. Geological Survey)

    Range of values
    Minimum:2010
    Maximum:2010
    Units:year

    jdtime
    Julian day and time of the start of the seismic trackline in the format JJJ:HH:MM:SS. The Julian day number is the integer number representing the interval of time in days since January 1 of the year. The time is in UTC time which is +4 hours from local time during the survey. (Source: U.S. Geological Survey)

    Character set.

    shot_end
    The shot number associated with the end of the line. (Source: U.S. Geological Survey)

    Range of values
    Minimum:505
    Maximum:8966
    Units:shot

    jdtime_end
    Julian day and time of the end of the seismic trackline in the format JJJ:HH:MM:SS. The Julian day number is the integer number representing the interval of time in days since January 1 of the year. The time is in UTC time which is +4 hours from local time during the survey. (Source: U.S. Geological Survey)

    Character set.

    lnkm_utm18
    Length of the line in kilometers based on UTM, Zone 18, WGS84. (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.139245
    Maximum:3.491852
    Units:kilometers

    hotlink
    Text field which provides the partial path and full filename of the JPEG image of the seismic-reflection profile associated with the trackline. (Source: Data processor.)

    Character set.

    Entity_and_Attribute_Overview:
    In order to effectively utilize the "hotlink" attribute in ArcGIS, the user must follow a couple of steps. First, the user must open the Layer Properties of the shapefile within ArcMap - select the Display tab - and click on the check box next to "Support Hyperlinks using field:" and the field selected from the dropdown menu needs to be "hotlink". The hyperlink is set to a document. Additionally, a hyperlink base must be supplied in the ArcMap document (mxd) to complete the full path to the images. This is accomplished from File - Document Properties. On the Summary tab there is a section for "hyperlink base". The text supplied here needs to be the disk information preceding "data" in the full path to the image. If the data are being read from a DVD, this would be the drive letter such as F\.

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?

The purpose of this dataset is to provide the calibrated route polyline for the seismic-reflection profiles collected on USGS Field Activity 2010-006-FA. These lines are calibrated based on shot number so that using the route identifier tool allows the user to find the location of a specific shot on any seismic trackline. This helps correlate the seismic-reflection profiles with other GIS data available in the area.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Source_Contribution:
    The seismic acquisition system used on this cruise was an EdgeTech 424 Chirp sub-bottom system with a 4 to 24 kHz pulse bandwidth and a 2 ms pulse. The system towfish was attached by a short line to a cleat on a 2 x 6 board that was clamped across the bow of the boat. The towfish was on the starboard side of the boat, approximately 0.5 meters below the water surface. The acquisition software used to record the data was Discover 3100 version 7.01. The data were recorded in the SEG-Y data format IBM floating point with navigation supplied by the Lowrance GPS system. The navigation was recorded in the header of the seismic data in an arc second format. The record length is 133 ms, with a sample interval of 23 micro-seconds and 5788 samples per trace. The fire-rate was between 4 and 6 shots per second. The GPS antenna was located above the tow position of the seismic transducer.

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

    Date: Dec-2010 (process 1 of 10)
    The shapefile of the unique shot navigation, available from <http://pubs.usgs.gov/of/2011/1039/html/ofr2011-1039-catalog.html>, is the basis for this polyline shapefile. Using VACExtras v. 2.1 - VAC Extras - FeatConv - Points to Lines v2, convert the points to polylines. The attribute used as the unique line identifier is "linename". Also transferred were the first occurrence and last occurrence of "shot", "year", and "jdtime" to the output shapefile - ir_seisnav_lns.shp. This process step and all subsequent process steps were 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

    Data sources used in this process:
    • ir_seisnav.shp

    Data sources produced in this process:

    • ir_seisnav_lns.shp

    Date: Jan-2011 (process 2 of 10)
    Using ArcMap 9.2 - ArcToolbox - Linear Referencing Tools - Create Routes to convert the polyline to a route. The following parameters were used: input - ir_seisnav_lns; route identifier field - linename; output - ir_Routes.shp; measure source - length. The rest of the options were left to the default.

    Data sources used in this process:

    • ir_seisnav_lns.shp

    Data sources produced in this process:

    • ir_Routes.shp

    Date: Jan-2011 (process 3 of 10)
    Then the route was calibrated so the measurement units along the route are seismic shot numbers. Using ArcMap 9.2 - ArcToolbox - Linear Referencing Tools - Calibrate Routes. The following parameters were used: input - ir_Routes; route identifier field - linename; input point feature - ir_seisnav; point identifier field - linename; measure field - shot; output route feature class - ir_Routes_Calib.shp; measure calculation method - distance; search radius - 1 meter. Rest of the options left to their default values (checked).

    Data sources used in this process:

    • ir_Routes.shp

    Data sources produced in this process:

    • ir_Routes_Calib.shp

    Date: Jan-2011 (process 4 of 10)
    With the route calibrated, it's possible to extract information for the "measurement" information at a particular interval. In this case, the goal was to extract a point at the beginning and end of each line, as well as at a 100 shot interval. To do this, hatches were added to the calibrated route using ArcMap 9.2 by opening the layer properties and selecting the Hatches tab. Created a marker hatch interval of 100 for the Hatch Class, then for Hatch Def(1) placed a marker hatch every 1 hatch interval. From the Hatch Class - Add a Hatch Definition - Add End Hatch Definition - and set these to a marker Hatch. By displaying the labels for both Hatch Definitions, a quick comparison between the hatches and shot navigation made sure things are behaving as intended, then turned the labels off. What was left was simply the markers for the start and end of line, as well as a mark at the even 100 shot intervals.

    Data sources used in this process:

    • ir_Routes_Calib.shp

    Data sources produced in this process:

    • ir_Routes_Calib.shp

    Date: Jan-2011 (process 5 of 10)
    Within ArcMap 9.2 - went to Tools - Customize - Commands and scrolled down to the Category "Linear Referencing", the icon for the command "Convert Hatches to Graphics was added to a toolbar. Once this was done, the tool was used to convert the hatches to graphics.

    Data sources used in this process:

    • ir_Routes_Calib.shp

    Data sources produced in this process:

    • graphics points

    Date: Jan-2011 (process 6 of 10)
    Converted these graphics to a shapefile using XTools Pro version 5.2. XTools Pro - Feature Conversions - Convert Graphics to Shapes. Source graphics layer: default, graphics element type: points. Output: ir_100shot_graphics.shp

    Data sources used in this process:

    • graphics points

    Data sources produced in this process:

    • ir_100shot_graphics.shp

    Date: Jan-2011 (process 7 of 10)
    These newly created points had no attribute information and needed to be related back to the polyline and extract the shot information. Used ArcMap 9.2 - ArcToolbox - Linear Referencing Tools - Locate Features Along Route. Used the following parameters: input - ir_100shot_graphics; input route features - ir_Routes_Calib; route identifier field - linename; search radius - 5 meters; output event table - ir_100shot_locateFeatures.dbf. Output event table properties: route identifier field - linename; event type - point (default); measure field - shot; left rest of options at default (all checked).

    Data sources used in this process:

    • ir_100shot_graphics.shp

    Data sources produced in this process:

    • ir_100shot_locateFeatures.dbf

    Date: Jan-2011 (process 8 of 10)
    Within the attribute table of the calibrated polyline shapefile, the following attributes were added: shot, year, jdtime, shot_end, jdtime_end. The calibrated polyline shapefile was then joined to the ir_seisnav_lns polyline shapefile based on the attribute "linename". This join was performed by right mouse click on ir_Routes_Calib - joins and relates - join. With the attributes of ir_seisnav now part of the ir_Routes_Calib attribute table, field calculator was used to populate the newly created attributes in the route shapefile based on the information in the ir_seisnav_lns attribute table.

    Data sources used in this process:

    • ir_seisnav_lns.shp
    • ir_Routes_Calib.shp

    Data sources produced in this process:

    • ir_Routes_Calib.shp

    Date: Jan-2011 (process 9 of 10)
    Using XTools Pro v. 5.2, the length of each polyline was added to the shapefile. XTools Pro - Table Operations - Calculate Area, Perimeter, Length, Acres and Hectares. The output projection was set to UTM, Zone 18, WGS84 with the desired output units of kilometers. The field name was specified as lnkm_utm18.

    Data sources used in this process:

    • ir_Routes_Calib.shp

    Data sources produced in this process:

    • ir_Routes_Calib.shp

    Date: Mar-2011 (process 10 of 10)
    In ArcMap 9.2 one additional attribute was added to the shapefile: hotlink. This attribute will allow the user to hyperlink to the JPEG images of the seismic-reflection profile from within ArcMap. See the entity and attribute overview for instructions on how to implement this feature.

    Data sources used in this process:

    • ir_Routes_Calib.shp

    Data sources produced in this process:

    • ir_Routes_Calib.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 above the seismic towfish tow point. The system towfish was attached by a short line to a cleat on a 2 x 6 board that was clamped across the bow of the boat. The towfish was on the starboard side of the boat, approximately 0.5 meters below the water surface. GPS data are assumed to be accurate within 10 meters on this survey.

  3. How accurate are the heights or depths?

    Although bathymetry was not recorded directly with this system, bathymetry can be derived by tracing the seafloor reflector in the seismic-reflection profiles. The seismic towfish was attached to a cleat by a short line on the starboard side of the boat. The transducer draft was approximately 0.5 m below the water surface. The draft offset was not included in the data acquisition.

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

    All of the shot point navigation from this cruise was incorporated in this shapefile.

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

    No additional checks for topological consistency 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 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 polyline 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 16:05:16 2014