Text files of the navigation logged during field activity 2012-035-FA by the U.S. Geological Survey and Massachusetts Office of Coastal Zone Management in Ipswich Bay and Massachusetts Bay, Massachusetts, in August 2012 (ASCII text and CSV files)

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Frequently anticipated questions:


What does this data set describe?

Title:
Text files of the navigation logged during field activity 2012-035-FA by the U.S. Geological Survey and Massachusetts Office of Coastal Zone Management in Ipswich Bay and Massachusetts Bay, Massachusetts, in August 2012 (ASCII text and CSV files)
Abstract:
Accurate data and maps of sea-floor geology are important first steps toward protecting habitat, delineating marine resources, and assessing environmental changes due to natural or human effects. Initiated in 2003, the primary objective of the Geologic Mapping of the Massachusetts Sea Floor program is to develop regional geologic framework information for the management of coastal and marine resources. The program is focused on the inshore waters (primarily 5-30 meters deep, although the region surveyed in this field activity includes waters up to 90 meters deep) of Massachusetts. This dataset, collected aboard the Ocean Survey Vessel (OSV) Bold as part of the Geologic Mapping of the Massachusetts Sea Floor Program, is from U.S. Geological Survey (USGS) sampling survey 2012-035-FA (August 21-27, 2012) by the USGS Woods Hole Coastal and Marine Science Center and the Massachusetts Office of Coastal Zone Management with partners from the Massachusetts Bays Program, the Massachusetts Department of Environmental Protection, the Massachusetts Division of Marine Fisheries, and the U.S. Environmental Protection Agency. During the survey, surficial sediment samples and bottom still and video imagery were collected in Ipswich Bay and Massachusetts Bay, Massachusetts.
Supplemental_Information:
During the survey, bottom still and video imagery was taken at each station (see shapefiles 2012-035-FA_photos.shp and 2012-035-FA_videos.shp available from the larger work citation; see the Coastal and Marine Geology Program Video and Photograph Portal to view the bottom videos [Golden and others, 2015; link available from the cross-reference citation]). Physical sediment samples were also collected at many stations and analyzed for grain size (see shapefile 2012-035-FA_samples.shp available from the larger work citation) and benthic infauna (see report by the Massachusetts Office of Coastal Zone Management [2013] available from the cross-reference citation). For more information about this field activity, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2012-035-FA. For more information about the Geologic Mapping of the Massachusetts Sea Floor program, see https://woodshole.er.usgs.gov/project-pages/coastal_mass/.
  1. How might this data set be cited?
    U.S. Geological Survey, 2018, Text files of the navigation logged during field activity 2012-035-FA by the U.S. Geological Survey and Massachusetts Office of Coastal Zone Management in Ipswich Bay and Massachusetts Bay, Massachusetts, in August 2012 (ASCII text and CSV files): data release DOI:10.5066/P924M8R1, 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.

    Huntley, Emily C., Ackerman, Seth D., Boeri, Robert L., Callaghan, Todd P., Sampson, Daniel W., and Blackwood, Dann S., 2018, Sampling data collected in Ipswich Bay and Massachusetts Bay, Massachusetts, in 2012, U.S. Geological Survey Field Activity 2012-035-FA: data release DOI:10.5066/P924M8R1, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Huntley, E.C., Ackerman, S.D., Boeri, R.L., Callaghan, T.P., Sampson, D.W., and Blackwood, D.S., 2018, Sampling data collected in Ipswich Bay and Massachusetts Bay, Massachusetts, in 2012, U.S. Geological Survey Field Activity 2012-035-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P924M8R1.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.921547
    East_Bounding_Coordinate: -70.480715
    North_Bounding_Coordinate: 42.874028
    South_Bounding_Coordinate: 42.295625
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 21-Aug-2012
    Ending_Date: 27-Aug-2012
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tabular digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set.
    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?
    Entity_and_Attribute_Overview:
    The 12 National Marine Electronics Association (NMEA) strings stored in the raw navigation files are described below. The CSV files only contain the GPRMC navigation string parsed from the raw navigation files for each Julian day. No editing has been conducted on these data. The times recorded in the navigation files are in UTC.
    $GPRMC is the recommended minimum Global Positioning System (GPS) data. For example, "$GPRMC,172814,A,4221.9562,N,07055.2928,W,9.1,51.3,210812,15.7,W,D*18" where:
    172814 = Fix taken at 17:28:14 UTC
    A = Status (A = active, V = void)
    4221.9562,N = Latitude 42 degrees 21.9562 minutes North
    07055.2928,W = Longitude 070 degrees 55.2928 minutes West
    9.1 = Speed over the ground in knots
    51.3 = Track angle in degrees true
    210812 = UTC date August 21, 2012
    15.7,W = Magnetic variation in degrees with direction (Westerly or Easterly)
    D = Mode indicator (A = Autonomous, D = Differential, E = Estimated, N = Data not valid)
    *18 = Checksum data, always begins with *
    $GPRMB is the recommended minimum navigation sentence. For example, "$GPRMB,A,0.66,L,003,004,4917.24,N,12309.57,W,001.3,052.5,000.5,V*20" where:
    A = Data status (A = active, V = void)
    0.66,L = Cross-track error in nautical miles (9.99 max), steer Left to correct (or R = right)
    003 = Origin waypoint ID
    004 = Destination waypoint ID
    4917.24,N = Destination waypoint latitude 49 degrees 17.24 minutes North
    12309.57,W = Destination waypoint longitude 123 degrees 09.57 minutes West
    001.3 = Range to destination in nautical miles (999.9 max)
    052.5 = True bearing to destination
    000.5 = Velocity towards destination in knots
    V = Arrival alarm (A = arrived, V = not arrived)
    *20 = Checksum data
    Note: The above example is from a different dataset. GPRMB strings were not transmitted during this survey and were therefore recorded as "$GPRMB,A,,,,,,,,,,,,V,D*19" in the raw navigation files.
    $GPGGA is essential GPS fix data. For example, "$GPGGA,172814,4221.9562,N,07055.2928,W,2,10,0.8,18.9,M,-33.0,M,,*45" where:
    172814 = Fix taken at 17:28:14 UTC
    4221.9562,N = Latitude 42 degrees 21.9562 minutes North
    07055.2928,W = Longitude 070 degrees 55.2928 minutes West
    2 = Fix quality (0 = invalid, 1 = GPS fix, 2 = DGPS fix, 3 = Precise Positioning System [PPS] fix, 4 = Real Time Kinematic [RTK] fix, 5 = RTK float, 6 = estimated, 7 = manual input mode, 8 = simulation mode)
    10 = Number of satellites being tracked
    0.8 = Horizontal dilution of position
    18.9,M = Altitude above mean sea level (geoid), meters
    -33.0,M = Height of geoid above WGS 84 ellipsoid, meters
    [Empty field] = Time in seconds since last DGPS update
    [Empty field] = DGPS station ID number
    *45 = Checksum data
    $GPGSA is overall satellite data. For example, "$GPGSA,A,3,01,03,06,07,08,11,13,17,19,,28,,0.0,0.8,0.8*3F" where:
    A = Auto selection of 2D or 3D fix (M = manual)
    3 = 3D fix (values include: 1 = no fix, 2 = 2D fix, 3 = 3D fix)
    01,03,06,07,08,11,13,17,19,,28,, = Pseudo-Random Noise (PRN) number of satellites used for fix (space for 12)
    0.0 = Position Dilution of Precision (PDOP)
    0.8 = Horizontal Dilution of Precision (HDOP)
    0.8 = Vertical Dilution of Precision (VDOP)
    *3F = Checksum data
    $GPGSV is data about the satellites in view. For example, "$GPGSV,3,1,12,01,41,157,48,03,21,059,48,06,08,058,33,07,64,197,45*7B" where:
    3 = Number of sentences for full data
    1 = Sentence 1 of 3
    12 = Number of satellites in view
    01 = Satellite PRN number
    41 = Elevation in degrees
    157 = Azimuth in degrees
    48 = Signal-to-Noise Ratio (SNR; higher is better)
    (The above four data fields may be repeated for up to four satellites per sentence. In the above example, they are repeated for four satellites.)
    *7B = Checksum data
    $GPGLL is geographic latitude and longitude data. For example, "$GPGLL,4221.9562,N,07055.2928,W,172814,A,D*52" where:
    4221.9562,N = Latitude 42 degrees 21.9562 minutes North
    07055.2928,W = Longitude 070 degrees 55.2928 minutes West
    172814 = Fix taken at 17:28:14 UTC
    A = Data status (A = active, V = void)
    D = Mode indicator (A = Autonomous, D = Differential, E = Estimated, N = Data not valid)
    *52 = Checksum data
    $GPBOD is bearing origin to destination data. For example, "$GPBOD,045.,T,023.,M,DEST,START*01" where:
    045.,T = Bearing 045 degrees True from "START" to "DEST"
    023.,M = Bearing 023 degrees Magnetic from "START" to "DEST"
    DEST = Destination waypoint ID
    START = Origin waypoint ID
    *01 = Checksum data
    Note: The above example is from a different dataset. GPBOD strings were not transmitted during this survey and were therefore recorded as "$GPBOD,,T,,M,,*47" in the raw navigation files.
    $GPVTG is velocity made good and ground speed data. For example, "$GPVTG,51.3,T,67.0,M,9.1,N,16.9,K,D*16" where:
    51.3,T = True track made good in degrees
    67.0,M = Magnetic track made good in degrees
    9.1,N = Ground speed, knots
    16.9,K = Ground speed, kilometers per hour
    D = Mode indicator (A = Autonomous, D = Differential, E = Estimated, N = Data not valid)
    *16 = Checksum data
    $PGRME is a Garmin proprietary sentence about the estimated position error ("P" denotes proprietary, "GRM" is Garmin's manufacturer code, and “E” indicates the specific sentence type). For example, "$PGRME,2.5,M,3.1,M,4.0,M*2F" where:
    2.5,M = Estimated Horizontal Position Error (HPE), meters
    3.1,M = Estimated Vertical Position Error (VPE), meters
    4.0,M = Overall spherical equivalent position error, meters
    *2F = Checksum data
    $PGRMZ is a Garmin proprietary sentence with altitude information ("P" denotes proprietary, "GRM" is Garmin's manufacturer code, and “Z” indicates the specific sentence type). For example, "$PGRMZ,55,f,*18" where:
    55,f = Altitude, feet
    [Empty field] = Position fix dimensions (2 = user altitude, 3 = GPS altitude)
    *18 = Checksum data
    Note: This sentence shows in feet, regardless of units shown on the display. For units with an altimeter, the altitude will be computed by the internal altimeter.
    $PGRMM is a Garmin proprietary sentence about the map datum ("P" denotes proprietary, "GRM" is Garmin's manufacturer code, and “M” indicates the specific sentence type). For example, "$PGRMM,WGS 84*06" where:
    WGS 84 = Currently active horizontal datum
    *06 = Checksum data
    $HCHDG is data about the magnetic heading, deviation, and variation. This string is used on Garmin eTrex Summit, Vista, and GPSMAP 76S receivers to output the value of the internal flux-gate compass. Only the magnetic heading and magnetic variation is shown in the message. For example, "$HCHDG,67.0,,,15.7,W*39" where:
    67.0 = Heading
    ,, = Deviation (no data)
    15.7,W = Variation and direction
    *39 = Checksum data
    $GPRTE is sent to indicate the names of the waypoints used in an active route. For example, "$GPRTE,1,1,c,*37" where:
    1 = Total number of sentences for full data
    1 = Sentence 1 of 1
    c = Type (c = complete list of waypoints in this route, w = first listed waypoint is start of current leg)
    [Empty field] = Route identifier
    [Empty fields] = Waypoint identifiers (names)
    *37 = Checksum data
    Entity_and_Attribute_Detail_Citation:
    The definitions of the NMEA strings were obtained from http://www.gpsinformation.org/dale/nmea.htm.

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?
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov

Why was the data set created?

These navigation data are provided as an archive of the navigation data files acquired during USGS survey 2012-035-FA offshore of Massachusetts in Ipswich Bay and Massachusetts Bay.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: Aug-2012 (process 1 of 3)
    DGPS navigation from a Garmin GPSMAP 76CSx receiver was logged through a Microsoft HyperTerminal (version 5.1) session on a Dell Latitude D820 laptop computer running Windows XP SP2 via serial cable. The DGPS was set to receive fixes at a two-second interval in geographic coordinates (World Geodetic System of 1984 [WGS 84]). Log files were saved approximately for each Julian day in ASCII text format. The filenames are in the format of BOLD_JD[Julian day]_[UTC start time in the format hhmm].txt. For example, filename BOLD_JD234_1728.txt represents the raw navigation logged beginning on Julian day 234 at 17:28. Dates and times were recorded in UTC. This process step and the subsequent process step were performed by the same person, Seth Ackerman. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Data sources produced in this process:
    • Raw navigation files
    Date: Sep-2012 (process 2 of 3)
    The raw log files were reformatted into log files by full Julian day based on UTC time. An AWK script (awkseth.gprmc.12035.awk) was run on the log files to parse for the GPRMC navigation string and create ASCII Comma Separated Value (CSV) text files. The GPRMC parsed navigation filenames are in the format of JD[Julian day]_GPRMC.csv. For example, filename JD234_GPRMC.csv represents the GPRMC navigation logged on Julian day 234. Data sources used in this process:
    • Raw navigation files
    Data sources produced in this process:
    • GPRMC parsed navigation files
    Date: 08-Sep-2020 (process 3 of 3)
    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?
    Golden, Nadine E., Ackerman, Seth D., and Dailey, Evan T., 2015, Coastal and Marine Geology Program video and photograph portal: U.S. Geological Survey, Santa Cruz, CA.

    Online Links:

    Massachusetts Office of Coastal Zone Management, 2013, ENV13 CZM 01 Benthic Infaunal Analysis Report: Massachusetts Office of Coastal Zone Management, Boston, MA.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Some lines of navigation data may be empty or incomplete, especially at the beginning of the raw (ASCII text) files when the first bits of data were being received via serial input.
  2. How accurate are the geographic locations?
    Navigation for survey 2012-035-FA used Differential Global Positioning System (DGPS). The recorded position of each navigation point is the position of the DGPS antenna on the survey vessel, not the SEABed Observation and Sampling System (SEABOSS) sampler. The antenna was mounted at the top of the vessel's A-frame from which the sampler was deployed, within a few meters of the sampler (+/- 3 meters). No layback or offset was applied to the recorded position. In addition to the +/- 3-meter offset, the sampler may drift away from the survey vessel when deployed to the sea floor. Based on the various sources of horizontal offsets, a conservative estimate of the horizontal accuracy of the bottom image, video trackline, and sediment sample locations is 10 meters.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    These files represent all the navigation recorded by the Microsoft HyperTerminal session during USGS survey 2012-035-FA. Navigation was not recorded at station 77 due to a system malfunction and is therefore missing from this dataset.
  5. How consistent are the relationships among the observations, including topology?
    The raw files were recorded by a Microsoft HyperTerminal session and were logged approximately for each Julian day. The GPRMC parsed navigation files were created by splitting and combining the raw files for each Julian day of surveying based on Coordinated Universal Time (UTC; starting at time 000000, ending at 235959). The files include navigation data logged during the transits en route to, returning from, and between the sampling sites. In general, the navigation feed was continuous, even during breaks in the sampling survey, although some gaps in the navigation data may occur during the transit times. Records of well-formatted yet erroneous navigation fixes may occur but were not checked, removed, or corrected.

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)
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
  2. What's the catalog number I need to order this data set? USGS data release 2012-035-FA contains navigation files collected offshore of Massachusetts in Ipswich Bay and Massachusetts Bay (2012-035-FA_nav.zip). The zip file contains a folder named "raw" that includes eight ASCII text files that serve as a navigation archive (BOLD_JD234_1728.txt, BOLD_JD235_0000.txt, BOLD_JD235_2252.txt, BOLD_JD236_0000.txt, BOLD_JD237_0021.txt, BOLD_JD238_0002.txt, BOLD_JD239_0004.txt, and BOLD_JD240_0006.txt), a folder called "processed" that contains seven CSV files parsed for the GPRMC navigation string (JD234_GPRMC.csv, JD235_GPRMC.csv, JD236_GPRMC.csv, JD237_GPRMC.csv, JD238_GPRMC.csv, JD239_GPRMC.csv, and JD240_GPRMC.csv), and Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM) metadata files in three standard formats (2012-035-FA_nav_meta.html, 2012-035-FA_nav_meta.txt, and 2012-035-FA_nav_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?
    This zip file contains data available as ASCII text and CSV files. To utilize these data, the user must have software capable of viewing text files.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
Emily Huntley
U.S. Geological Survey
Geographer/Database Specialist
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 (voice)
508-457-2310 (FAX)
ehuntley@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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