Sound Velocity Profiles, Odim MVP 30 sound velocity profile data, USGS field activity 2017-003-FA, Mississippi River Delta front offshore of southeastern Louisiana (PNG images, ASVP text, and Esri point shapefile, GCS WGS 84).

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Frequently anticipated questions:


What does this data set describe?

Title:
Sound Velocity Profiles, Odim MVP 30 sound velocity profile data, USGS field activity 2017-003-FA, Mississippi River Delta front offshore of southeastern Louisiana (PNG images, ASVP text, and Esri point shapefile, GCS WGS 84).
Abstract:
High resolution bathymetric, sea-floor backscatter, and seismic-reflection data were collected offshore of southeastern Louisiana aboard the research vessel Point Sur on May 19-26, 2017, in an effort to characterize mudflow hazards on the Mississippi River Delta front. As the initial field program of a research cooperative between the U.S. Geological Survey, the Bureau of Ocean Energy Management, and other Federal and academic partners, the primary objective of this cruise was to assess the suitability of sea-floor mapping and shallow subsurface imaging tools in the challenging environmental conditions found across delta fronts (for example, variably distributed water column stratification and widespread biogenic gas in the shallow subsurface). Approximately 675 kilometers (km) of multibeam bathymetry and backscatter data, 420 km of towed chirp data, and 550 km of multichannel seismic data were collected. Varied mudflow (gully, lobe), prodelta morphologies, and structural features were imaged in selected survey areas from Pass a Loutre to Southwest Pass.
Supplemental_Information:
Additional information on the field activity is available from https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-003-FA.
  1. How might this data set be cited?
    U.S. Geological Survey, 2018, Sound Velocity Profiles, Odim MVP 30 sound velocity profile data, USGS field activity 2017-003-FA, Mississippi River Delta front offshore of southeastern Louisiana (PNG images, ASVP text, and Esri point shapefile, GCS WGS 84).: data release DOI:10.5066/F7X929K6, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Baldwin, Wayne E., Ackerman, Seth D., Worley, Charles R., Danforth, William W., and Chaytor, Jason D., 2018, High-resolution geophysical data collected along the Mississippi River Delta front offshore of southeastern Louisiana, U.S. Geological Survey Field Activity 2017-003-FA: data release DOI:10.5066/F7X929K6, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Baldwin, W.E., Ackerman, S.D., Worley, C.R., Danforth, W.W., and Chaytor, J.D, 2018, High-resolution geophysical data collected along the Mississippi River Delta front offshore of southeastern Louisiana, U.S. Geological Survey Field Activity 2017-003-FA: U.S. Geological Survey data release, https://doi.org/10.5066/F7X929K6.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.541089
    East_Bounding_Coordinate: -88.867156
    North_Bounding_Coordinate: 29.375350
    South_Bounding_Coordinate: 28.777921
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5a9470d1e4b069906068fbbe/?name=2017-003-FA_MVPdata_browse.jpg (JPEG)
    Thumbnail image of Mississippi River Delta front sound speed profile locations.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 21-May-2017
    Ending_Date: 26-May-2017
    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):
      • point (74)
    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?
    2017-003-FA_MVPdata
    Sound velocity profile locations for survey 2017-003-FA along the Mississippi River Delta front. (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    Lon
    Decimal degree longitude value in GCS WGS 84. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-89.541089
    Maximum:-88.867156
    Units:degrees
    Resolution:.000001
    Lat
    Decimal degree latitude value in GCS WGS 84. (Source: U.S. Geological Survey)
    Range of values
    Minimum:28.777921
    Maximum:29.37535
    Units:degrees
    Resolution:.000001
    MVP
    Name of velocity profile used to distinguish between casts. Profile names beginning with 'MVP30' refer to the MVP30 moving vessel profiler casts (and are followed by cast number - 0001 to 0076). (Source: U.S. Geological Survey) character set
    Date
    Month/day/year when the MVP cast was collected. (Source: U.S. Geological Survey) character set
    JD_UTC
    Julian day and UTC time when the MVP cast was collected in the format: JD:HH:MM; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) character set
    SurveyID
    WHMSC field activity identifier (e.g. "2017-003-FA" where 2017 is the survey year, 003 is survey number of that year, and FA is field activity). (Source: U.S. Geological Survey) character set
    VehicleID
    Survey vessel name. (Source: U.S. Geological Survey) character set
    DeviceID
    Device used to collect sound speed profile data. (Source: U.S. Geological Survey) character set
    ImageLink
    Name of the PNG image file associated with the MVP cast. (Source: U.S. Geological Survey) Character set
    Entity_and_Attribute_Overview:
    The PNG images can be hyperlinked to their shapefile location in ArcGIS. The graphs show depth on the y-axis and speed of sound on the x-axis. In addition to the graphs, the ASCII data is also available in ASVP files. The format of the ASVP files is as follows:
    Header row: soundvelocity (file type), 1.00 (file format version number), cast number in filename (xxx), date/time of file creation (yyyymmddhhmm), latitude (decimal degrees), longitude (decimal degrees), radii around the lat/long position for which the profile is valid (set to 1 meter), date of profile start (yyyymmddhhmm), date of profile stop (yyyymmddhhmm), source instrument of the profile (MVP p or smartprobe p where p stands for probe), number of values in the profile.
    Remaining rows: column data of depth (meters) and speed of sound (meters per second) space delimited.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Wayne E. Baldwin
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov

Why was the data set created?

This dataset is used to display the locations of sound velocity profiles (SVP, also referred to as sound speed profiles), as well as the SVP data, collected during a 2017 USGS cruise along the Mississippi River Delta front. The sound velocity profiles document water column sound speed variability during the cruise, and were used during processing to account for refraction artifacts present within the multibeam bathymetric data. The dataset contains graphs of the sound velocity profile at each station location, as well as location in Geographic Coordinate System (GCS) WGS 84 latitude and longitude, the time of day, and date of collection.

How was the data set created?

  1. From what previous works were the data drawn?
    raw sound velocity data (source 1 of 1)
    U.S. Geological Survey, unpublished material, sound velocity data.

    Type_of_Source_Media: disc
    Source_Contribution:
    Sound velocity profiles were collected using an ODIM MVP30 moving vessel profiler (MVP) mounted on the stern. MVP (version 2.391) acquisition software running on a laptop PC controlled the smart winch and deployment system, allowing free fall deployment of the MVP fish at a user specified time interval while the vessel was underway. An AML Oceanographic MVP X SVPT probe attached to the tow body collected sound velocity, pressure, and temperature data during each deployment. Data were transmitted via the coaxial tow cable to the acquisition PC and data collected during the downcast portions of the deployment were logged to the Kongsberg SIS ASVP ASCII format. Position data were supplied to the MVP30 topside via a serial connection from HYPACK (17.0.26.0) survey software, and logged to the ASVP format files.
  2. How were the data generated, processed, and modified?
    Date: May-2017 (process 1 of 3)
    SVP profile acquisition at sea:
    Sound velocity profiles were collected every 1-5 hours and sometimes more frequently using the ODIM MVP30 moving vessel profiler from 20170521 to 20170526 (jd 141-146).
    This process step and all subsequent process steps were conducted by the same person - Wayne Baldwin. Person who carried out this activity:
    Wayne E. Baldwin
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2226 (voice)
    (508) 457-2310 (FAX)
    wbaldwin@usgs.gov
    Date: May-2017 (process 2 of 3)
    Plot the SVP data and import into Spatialite database:
    A python script was used to read the ASVP data and plot the sound speed profile as speed of sound (meter/second) versus depth (meters). Position, date, time, and profile id were pulled from the asvp header and written into the image (PNG) for reference. Within the same script, the position, Julian day, time, and profile id were also imported into a Spatialite (version 4.3.0) enabled SQLite (version 3.21.0) database table. The geographic positions were used to create point geometries for the station locations, and additional fields indicating Survey_ID, Vessel_ID, Device_ID, and ImageLink were added.
    Date: Nov-2017 (process 3 of 3)
    Create Esri shapefile containing the point data:
    The MVP point features were added (Add Data) into ArcMap (version 10.3.1) from the SQLite database, then exported (Right click on database feature class > Data > Export Data) to the new Esri point shapefile 2017-003-FA_MVPdata.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?
    DGPS navigation data for the sound velocity profiles were acquired using the WGS 84 coordinate system with an Applanix POS MV Wavemaster (model 220, V5) with two AeroAntenna Technologies GPS antennas located at either end of a 2-m baseline, which was oriented fore and aft and mounted atop the MBES pole, approximately midships on the starboard side of vessel. Position data were supplied to the MVP30 topside via a serial connection from HYPACK (17.0.26.0) survey software. While the horizontal position accuracy is thought to be within 0.5 - 2 meters for the DGPS position solutions, we consider the sound velocity profile positions to be within 10 m, since the location of the MVP30 smart winch, which was used to deploy the MVP while underway, approximately 8 meters aft of the MBES pole was not accounted for.
  3. How accurate are the heights or depths?
    MVP30 tow fish depths are calculated by the MVP (version 2.391) acquisition software, which converts pressure sensor readings to depth using the standard formulas described in Fofonoff, N.P.and Millard, R.C., Jr., 1988, Algorithms for computation of fundamental properties of seawater, UNESCO Technical Papers in Marine Science, No. 44. The depths are thought to be accurate to within 1 meter.
  4. Where are the gaps in the data? What is missing?
    Each sound velocity profile (74 total) collected during cruise 2017-003-FA is represented by an ASVP formated ASCII text file (see description below in the entity and attribute overview section), a PNG image file, and a feature point location in the Esri shapefile. Profiles MVP30__0046 and MVP30__0057 were faulty and excluded during QA/QC processing.
  5. How consistent are the relationships among the observations, including topology?
    Sound velocity profiles were acquired with an ODIM MVP30 moving vessel profiler (MVP) from 20170521 to 20170526 (jd 141-146). No sound speed profiles were collected between 14:38 and 18:28 UTC on 20170522 (jd 142) while the MVP30 was inoperable due to cable failure. These data only contain the downcast data collection.

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:
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)
    U.S. Geological Survey - ScienceBase
    Federal Center
    Denver, CO

    1-888-275-8747 (voice)
  2. What's the catalog number I need to order this data set? USGS data release 2017-003-FA MVP30 data from the Mississippi River Delta front area: includes the shapefile 2017-003-FA_MVPdata.shp, the zip archive 2017-003-FA_MVP_Images.zip containing 74 PNG images that represent all sound velocity profiles graphically, the zip archive 2017-003-FA_MVP_ASVP.zip containing 74 ASVP ASCII files that represent all sound velocity profiles, the browse graphic 2017-003-FA_MVPdata_browse.jpg, and the Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file 2017-003-FA_MVPdata_meta.xml.
  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?
    For the shapefile and web services data, the user must have software capable of reading shapefile format, or GIS software capable of utilizing web mapping or feature services. The ASVP files can be read with a text editor. PNG files can be viewed with any PNG image viewing software. The Zip files must be uncompressed to utilize the ASCII text files or view the images.

Who wrote the metadata?

Dates:
Last modified: 01-Mar-2018
Metadata author:
Wayne E. Baldwin
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA

(508) 548-8700 x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Metadata standard:
fgdc content standards for digital geospatial metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/data_release/DR_F7X929K6/2017-003-FA_MVPdata_meta.faq.html>
Generated by mp version 2.9.49 on Mon Sep 10 17:44:59 2018