Point Shapefile of 500 Shot Interval Point Navigation For Seismic Data Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006 on USGS Cruise 06018 (SHOT500SORT_GEOG.SHP)

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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 data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Bratton, John F., Foster, David S., and Cross, VeeAnn A., 2010, Point Shapefile of 500 Shot Interval Point Navigation For Seismic Data Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006 on USGS Cruise 06018 (SHOT500SORT_GEOG.SHP): Open-File Report 2009-1151, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.3133/ofr20091151
   • http://pubs.usgs.gov/of/2009/1151/data/navigation/seismics/shot500sort_geog.zip
   • http://pubs.usgs.gov/of/2009/1151/html/catalog.html

   This is part of the following larger work.
   Cross, VeeAnn A., Foster, David S., and Bratton, John F., 2010, Continuous Resistivity Profiling and Seismic-Reflection Data Collected in 2006 from the Potomac River Estuary, Virginia and Maryland: Open-File Report 2009-1151, U.S. Geological Survey, Reston, VA.

   Online Links:

   • http://pubs.usgs.gov/of/2009/1151/

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -76.856460
   East_Bounding_Coordinate: -76.310250
   North_Bounding_Coordinate: 38.295665
   South_Bounding_Coordinate: 37.946077
   

3. What does it look like?

   http://pubs.usgs.gov/of/2009/1151/data/navigation/seismics/shot500sort_geog.gif (GIF)

   Thumbnail image showing the location of the 500 shot interval seismic navigation collected from Sept. 6-8, 2006. The coastline is included for spatial reference.

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

   Beginning_Date: 06-Sep-2006

   Ending_Date: 08-Sep-2006

   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 (842)
   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.
      
7. How does the data set describe geographic features?

   shot500sort_geog

   Shapefile attribute table. (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 acquisition. (Source: Software generated.) Text field identifying the line.

   shot

   The seismic shot number associated with the navigation fix. (Source: Software generated.)

   Range of values
   Minimum:	1
   Maximum:	19,999
   Units:	shot number

   Distance

   The distance (in meters) that the point falls off the calibrated route polyline. (Source: ESRI Linear Referencing - Locate Feature Along Routes tool)

   Range of values
   Minimum:	0
   Maximum:	0
   Units:	meters

   Id

   An attribute carried over when the graphics hatches were converted to a shapefile. (Source: Software generated (XTools Pro))

   Value	Definition
   0	An element ID field generated when graphics are converted to a shapefile. The default value of 0 is supplied to all features upon creation.

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
   • David S. Foster
   • VeeAnn A. Cross
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
   

   (508) 548-8700 x2254 (voice)

   (508) 457-2310 (FAX)

   jbratton@usgs.gov

Why was the data set created?

The purpose of this layer is to provide all of the 500 shot point navigation associated with the seismic-reflection profiles collected on USGS cruise 06018. This information can help spatially correlate the seismic-reflection profiles with other features and data in the GIS.

How was the data set created?

1. From what previous works were the data drawn?

   raw seismic data (source 1 of 1)

   U.S. Geological Survey, Unpublished material, Raw Seismic Data.

   Type_of_Source_Media: hard disk
   Source_Contribution:

   The seismic acquisition system used on this cruise was a Knudsen Engineering Limited (KEL)1600 USB system. The system has up to 1.2 kW power and is tuned to work with two Massa 3.5 kHz transducers. The transducers were mounted on an over-the-side mount on the port side of the ship. The transducer draft was 0.7 m below the water surface. This draft offset was not included in the data acquisition. The seismic data acquisition software was SounderSuite-USB Beta. This system failed to acquire navigation data from the DGPS NEMA string on the first two days (Julian day 149 and 150). The software was also not able to record data in SEG-Y standard format. KEL KEB format files were logged to disk. In addition, KEA ASCII files with shot (ping) numbers and times were saved to disk. Shot point navigation was also absent in the KEA files on Julian days 149 and 150. On Julian day 151 a patched version of SounderSuite was received and installed. This version recorded navigation in the KEB and KEA files. SEG-Y recording was still not an option. A time server was used to synchronize the DGPS time on the KEL and HYPACK navigation systems. This was important as KEL SounderSuite records system time. Data were acquired at a 20 micro-second sample interval, 2048 samples for a 40 ms record length. Fire-rate was 0.20 seconds (or 5 shots per second). The KEL SounderSuite software was set up to automatically switch files at shot 20,000. Line 5 switched from file 0005_2006_249_2014_002.keb after shot 13509 to a new file (0005_2006_249_2014_003.keb) while changing display parameters, due to a bug in the acquisition software.

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

   Date: 2006 (process 1 of 16)

   An ArcView 3.3 avenue script written in Woods Hole (point2line.ave) was used to connect the individual shot points using the attribute "linename" as the unique line identifier. That attribute is also brought over to the resulting polyline shapefile. This process step, as well as 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
   

   (508) 548-8700 x2251 (voice)

   (508) 457-2310 (FAX)

   vatnipp@usgs.gov

   Data sources used in this process:

   • allshots.shp

   Data sources produced in this process:

   • allshots_lns.shp

   Date: 2006 (process 2 of 16)

   Using ArcMap 9.0 - ArcToolbox - Data Management Tools - Define Projection the polyline shapefile projection was defined as UTM, zone 18, NAD83. Data sources used in this process:

   • allshots_lns.shp

   Data sources produced in this process:

   • allshots_lns.shp

   Date: 2006 (process 3 of 16)

   The polyline shapefile was converted to a route using ArcMap 9.0 - ArcToolbox - Linear Referencing Tools - Create Routes. The following tool parameters were used: Input line feature - allshots.shp; route identifier field - linename; output route feature class - allshots_route.shp. The rest of the parameters were left to the default values. This process step, as well as all subsequent process steps, were performed by the same person - VeeAnn A. Cross. Data sources used in this process:

   • allshots_lns.shp

   Data sources produced in this process:

   • allshots_route.shp

   Date: 2006 (process 4 of 16)

   This polyline route was then calibrated using ArcMap 9.0 - ArcToolbox - Linear Referencing Tools - Calibrate Routes. The following parameters were used: input route features - allshots_route.shp; route identifier field - linename; input point features - allshots.shp; point identifier field - linename; measure field - shot; output route feature class - allshots_route_Calibrate.shp; measure calculation method - distance; search radius 0. The rest of the parameters left at the default. Data sources used in this process:

   • allshots_route.shp
   • allshots.shp

   Data sources produced in this process:

   • allshots_route_Calibrate.shp

   Date: 2006 (process 5 of 16)

   Added hatches to the calibrated route using ArcMap 9.0 by opening the layer properties and selecting the Hatches tab. Create a hatch interval of 500 for the Hatch Class, then for Hatch Def(1) place 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 makes sure things are behaving as intended. Then turn the labels off. Data sources used in this process:

   • allshots_route_Calibrate.shp

   Data sources produced in this process:

   • allshots_route_Calibrate.shp

   Date: 2006 (process 6 of 16)

   Within ArcMap 9.0 - by going to Tools - Customize - Commands and scrolling down to the Category "Linear Referencing", the icon for the command "Convert Hatches to Graphics can be added to a toolbar. Once this is done, that tool can be used to convert the hatches to graphics.

   Date: 2006 (process 7 of 16)

   Convert these graphics to a shapefile using XTools Pro version 5.0. Data sources used in this process:

   • displayed graphic points

   Data sources produced in this process:

   • shot500graphics.shp

   Date: 2006 (process 8 of 16)

   Use ArcMap 9.0 - ArcToolbox - Linear Referencing Tools - Locate Features Along Route. The following parameters were used: Input Features:shot500graphics.shp; Input Route Features - allshots_route_Calibrate.shp; route identifier field - linename; Search Radius - 5 meters; output event table - shot500graphics_LocateFeatur.dbf; output route identifier field - linename; measure field - shot. All the rest of the parameters left to the default. Data sources used in this process:

   • shot500graphics.shp
   • allshots_route_Calibrate.shp

   Data sources produced in this process:

   • shot500graphics_LocateFeatur.dbf

   Date: 2006 (process 9 of 16)

   Convert the event layer to a shapefile by exporting the data (right mouse click on event layer, Data, Export Data). Data sources used in this process:

   • shot500graphics_LocateFeatur Events

   Data sources produced in this process:

   • shot500tmp.shp

   Date: 2006 (process 10 of 16)

   Using VACExtras version 1.95 (an ArcMap extension written in Woods Hole) in ArcMap 9.0 the attribute table of the shot navigation was sorted primarily by the attribute linename with a secondary sort field by the attribute shot. Data sources used in this process:

   • shot500tmp.shp

   Data sources produced in this process:

   • shot500sort.shp

   Date: 2006 (process 11 of 16)

   There are lines that show no break between files because the Knudsen was set to record data and automatically switch files every 20,000 shots. This made the last shot of one file the same as the first shot of the subsequent file. This leads to duplicate shot #1 at these bounds during linear referencing. The first shot #1 should really be shot 19999 of the previous file. To account for this, the attributes of the shapefile were edit to reflect this (effectively removing the duplicate shots). So for instance, two records have the linename 0001_2006_249_1447_002 and shot 1. The first record was changed to linename 001_2006_249_1340_001 with shot number 19999. This way, every shot has a unique line number - shot combination. Data sources used in this process:

   • shot500sort.shp

   Data sources produced in this process:

   • shot500sort.shp

   Date: 2009 (process 12 of 16)

   The shot point shapefile was reprojected to Geographic, NAD83 using ArcMap 9.2, ArcToolbox - Data management Tools - Projections and Transformations - Feature - Project. Because the input file and output file have the same datum, no datum transformation was required. Data sources used in this process:

   • shot500sort.shp

   Data sources produced in this process:

   • shot500sort_geog.shp

   Date: 27-Oct-2016 (process 13 of 16)

   Edits to the metadata were made to fix any errors that MP v 2.9.34 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. Other minor edits were probably performed (title, publisher, publication place, etc.). The source information was incomplete and had to be modified to meet the standard. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. 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 Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

   Date: 20-Jul-2018 (process 14 of 16)

   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

   Date: 18-Nov-2019 (process 15 of 16)

   Crossref DOI link was added as the first link in the metadata. 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

   Date: 08-Sep-2020 (process 16 of 16)

   Added keywords section with USGS persistent identifier as theme keyword. 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?
   A differential global positioning system (DGPS) was used for the seismic-reflection data. This system was an Ashtech DGPS2 with the navigation being recorded by HYPACK navigation software. The offset from the seismic transducer to the DGPS antenna was 2 meters. This offset was not entered into the software.
3. How accurate are the heights or depths?
   Although bathymetry was not recorded directly, bathymetry can be derived by tracing the seafloor reflector in the seismic-reflection profiles. The seismic transducers were mounted on an over the side mount on the port side of the ship. The transducer draft was 0.7 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?
   This shapefile represents the 500 shot interval navigation for all the seismic lines collected on this cruise.
5. How consistent are the relationships among the observations, including topology?
   These points were visually checked to make sure they were viable fixes.

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)
   
   John F. Bratton

   U.S. Geological Survey

   Woods Hole Coastal and Marine Science Center

   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?
   • Availability in digital form:

     Data format:	This WinZip file contains the point shapefile as well as the associated metadata files. in format Shapefile (version ArcGIS 9.2) Size: 0.058
     Network links:	http://pubs.usgs.gov/of/2009/1151/data/navigation/seismics/shot500sort_geog.zip http://pubs.usgs.gov/of/2009/1151/html/catalog.html
     Media you can order:	DVD-ROM (Density 4.75 GBytes) (format UDF)

   • Cost to order the data: None.

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: 08-Sep-2020

Metadata author:

VeeAnn A. Cross

U.S. Geological Survey

Marine Geologist

Woods Hole Coastal and Marine Science Center

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)