Split-beam Echo Sounder and Navigation Data Collected Using a Simrad EK80 Wide Band Transceiver and ES38-10 Transducer During the Mid-Atlantic Resource Imaging Experiment (MATRIX), USGS Field Activity 2018-002-FA

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Frequently anticipated questions:

What does this data set describe?

Title:
Split-beam Echo Sounder and Navigation Data Collected Using a Simrad EK80 Wide Band Transceiver and ES38-10 Transducer During the Mid-Atlantic Resource Imaging Experiment (MATRIX), USGS Field Activity 2018-002-FA
Abstract:
In summer 2018, the U.S. Geological Survey partnered with the U.S Department of Energy and the Bureau of Ocean Energy Management to conduct the Mid-Atlantic Resources Imaging Experiment (MATRIX) as part of the U.S. Geological Survey Gas Hydrates Project. The field program objectives were to acquire high-resolution 2-dimensional multichannel seismic-reflection and split-beam echo sounder data along the U.S Atlantic margin between North Carolina and New Jersey to determine the distribution of methane gas hydrates in below-sea floor sediments and investigate potential connections between gas hydrate dynamics and sea floor methane seepage. MATRIX field work was carried out between August 8 and August 28, 2018 on the research vessel Hugh R. Sharp and resulted in acquisition of more than 2,000 track-line kilometers of multichannel seismic-reflection and co-located split-beam echo sounder data, along with wide-angle seismic reflection and refraction data from 63 expendable sonobuoy deployments.
Supplemental_Information:
This research was supported by USGS Coastal and Marine Hazards and Resources Program, USGS-DOE interagency agreement DE-FE0023495, and USGS-BOEM interagency agreement M17PG00041. Additional information on the field activity is available from https://www.usgs.gov/centers/whcmsc/science/mid-atlantic-resource-imaging-experiment-matrix?qt-science_center_objects=0#qt-science_center_objects and https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-002-FA.
  1. How might this data set be cited?
    Baldwin, Wayne E., Bergeron, Emile M., Foster, David S., Moore, Eric M., Nichols, Alex R., O'Brien, Tom F., Miller, Nathaniel C., and Ruppel, Carolyn D., 20210115, Split-beam Echo Sounder and Navigation Data Collected Using a Simrad EK80 Wide Band Transceiver and ES38-10 Transducer During the Mid-Atlantic Resource Imaging Experiment (MATRIX), USGS Field Activity 2018-002-FA: data release DOI:10.5066/P948VJ4X, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Baldwin, W.E., Bergeron, E.M., Foster, D.S., Moore, E.M., Nichols, A.R., O'Brien, T.F., Miller, N.C., and Ruppel, C.D., 2021, Split-beam echo sounder and navigation data collected using a Simrad EK80 wide band transceiver and ES38-10 transducer during the Mid-Atlantic Resource Imaging Experiment (MATRIX), USGS field activity 2018-002-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P948VJ4X.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -74.838809
    East_Bounding_Coordinate: -70.887187
    North_Bounding_Coordinate: 39.029336
    South_Bounding_Coordinate: 34.780431
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5f4fdafa82ce4c3d123502e7/?name=2018-002-FA_EK80BrowseImage.jpg (JPEG)
    Split-beam echo sounder browse image.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 09-Aug-2018
    Ending_Date: 28-Aug-2018
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the 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 WGS 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    2018-002-FA_EK80Tracklines
    EK80 Tracklines for survey 2018-002-FA (605 polyline features). (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.
    LineName
    Name of the trackline along which split-beam echo sounder data were collected in the format: CruiseID_-Date-UTCStartTime (i.e.'2018-002-FA_-D20180809-T010303'). (Source: U.S. Geological Survey) Character set
    YJD_init
    Year and Julian day at the start of the survey line; 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
    JDUTC_init
    Julian day and UTC time at the start of the survey line in the format: JD:HH:MM:SS; 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
    YJD_end
    Year and Julian day at the end of the survey line; 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
    JDUTC_end
    Julian day and UTC time at the end of the survey line in the format: JD:HH:MM:SS; 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
    WHCMSC field activity identifier (e.g. "2018-002-FA" where 2018 is the survey year, 002 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
    Sonar device used to collect split-beam echo sounder data. (Source: U.S. Geological Survey) Character set
    Length_km
    Length of split-beam echo sounder data line in kilometers (UTM Zone 18N, WGS 84) calculated in the SQLite database. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.213
    Maximum:32.598
    Units:kilometers
    Resolution:0.001
    EK80_Image
    Name of the EK80 PNG profile image that includes data from the survey line. If no image is available for the survey line, the value is set to "no image available". (Source: U.S. Geological Survey) Character set
    2018-002-FA_EK80NavPoints_1min
    EK80 1-minute interval shot points for survey 2018-002-FA (25,328 point features). (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
    Longitude coordinate in decimal degrees, WGS 84, negative value indicates Western hemisphere. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-74.838809
    Maximum:-70.887205
    Units:degrees
    Resolution:1E-06
    Lat
    Latitude coordinate in decimal degrees, WGS 84 (Source: U.S. Geological Survey)
    Range of values
    Minimum:34.780446
    Maximum:39.029334
    Units:degrees
    Resolution:1E-06
    LineName
    Name of the trackline along which split-beam echo sounder data were collected in the format: CruiseID_-Date-UTCStartTime (i.e.'2018-002-FA_-D20180809-T010303'). (Source: U.S. Geological Survey) Character set
    Year_JD
    Year and Julian day for the navigation fix; 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
    JD_UTC
    Julian day and UTC time for of the navigation fix in the format: JD:HH:MM:SS; 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
    WHCMSC field activity identifier (e.g. "2018-002-FA" where 2018 is the survey year, 002 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
    Sonar device used to collect split-beam echo sounder data. (Source: U.S. Geological Survey) Character set
    2018-002-FA_EK80_Images
    Portable network graphic images of EK80 volume backscatter strength (Sv) profiles for survey 2018-002-FA (183 PNG images). (Source: U.S. Geological Survey)
    Entity_and_Attribute_Overview:
    The PNG profile images show volume backscatter strength (Sv) measured along the survey trackline. The y-axis (left margin) indicates depth in meters (relative to instantaneous sea level), the x-axis indicates UTC time along the profile trackline (labeled at 5-minute intervals), and the color bar along the right margin indicates Sv (in dB referenced to 1 inverse meter). The PNG images can be hyperlinked to their corresponding trackline in ArcGIS using the shapefile '2018-002-FA_EK80Tracklines.shp'. The 5-minute index annotations along the bottom of the PNG images correlate to the positions of associated times in '2018-002-FA_EK80NavPoints_1min.shp'.
    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)
    • Wayne E. Baldwin
    • Emile M. Bergeron
    • David S. Foster
    • Eric M. Moore
    • Alex R. Nichols
    • Tom F. O'Brien
    • Nathaniel C. Miller
    • Carolyn D. Ruppel
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Wayne E. Baldwin
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    US

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

Why was the data set created?

This dataset contains 1-minute navigation points, tracklines, and profile images for over 3100 km of Simrad EK80 split-beam echo sounder data collected by the U.S. Geological Survey during the Mid-Atlantic Resource Imaging Experiment (MATRIX; field activity 2018-002-FA). The data were acquired along portions of the U.S. Atlantic margin between Virginia and New Jersey to investigate potential connections between seafloor methane seepage and sub-seafloor gas hydrate dynamics. Images of the water column profile data were generated in order to provide portable and easily viewable alternatives to the Simrad raw versions of the data. This information allows for spatial correlation of the split-beam echo sounder profile images with other geophysical and sample data for investigating water column backscatter in relation to seafloor morphology and stratigraphy in the area.

How was the data set created?

  1. From what previous works were the data drawn?
    raw Simrad EK80 data (source 1 of 1)
    U.S. Geological Survey, unpublished material, raw Simrad EK80 data (*.raw).

    Type_of_Source_Media: disc
    Source_Contribution:
    Split-beam echo sounder data were collected using a Simrad EK80 wide band transceiver and ES38-10 split-beam transducer (38 kHz, 10-degree beam width). The ES38-10 transducer was mounted in a frame placed inside the retractable keel (rear of three slots) of the R/V Hugh R. Sharp, which is located approximately amidships on the center line of the vessel. Navigation for the EK80 was collected using a Wide Area Augmentation System (WAAS) enabled Hemisphere R131 Differential GPS (DGPS) receiver with the GPS antenna mounted on the aft 01 dark handrail approximately 3.4 meters aft of the ES38-10 transducer. While underway, the retractable keel was lowered to 1-meter below the hull, resulting in a draft of 5.06 meters below the waterline. Simrad EK80 (version 1.12.2.0) acquisition software was used to control the EK80 transceiver and digitally log the echogram data and NMEA GPS messages to the Simrad raw format. Data were acquired over record lengths up to 4000 meters (EK80 acquisition software used a constant sound speed of 1536.3 meters per second for two way travel time to depth conversion) using pulse lengths of 256, 512, 1204, and 2048 microseconds with output power ranging between 450 and 1200 Watts. Each of the pulse length used were calibrated using a 60-millimeter copper ball reference sphere prior to the start of survey and the resulting target strength corrections were used to update the beam data.
  2. How were the data generated, processed, and modified?
    Date: Dec-2020 (process 1 of 2)
    PROCESS STEP 1: ESP3 (version 1.8.1) and python were used to create volume backscatter strength (Sv) profile images of the split-beam echo sounder data, extract navigation data from the Simrad raw files, and process the extracted navigation data. The processing flows are summarized below.
    1) Simrad raw files were imported into ESP3 ('open file') by survey day. Using the 'layer list' tab, input files were evaluated for their time length and quality. Shorter files were concatenated ('merge selected layers') to produce continuous data sections approximately 1 to 4 hours long, and longer files were left as is. Files in which acquisition settings caused changes in sample rate mid-file, an issue that ESP3 recognizes but does not correct for, were generally not concatenated or included as the last file in a longer concatenated section (see logical consistency report for a list of files effected by this issue). Settings in the 'Display Options' tab determined several elements of the images produced; 'Data' was always set to 'Sv' (in dB referenced to 1 inverse meter), X-Scale was always set to 300 seconds (for 5 minute annotation interval), the Y-Scale varied between 10 and 500 meters depending on the duration of the image, and default values were left in remaining fields. For each of the desired output sections, the zoom tool was used to restrict the image area to be above the deepest sea floor depth, and 'Export > Save Echogram' was used to create an output PNG file of the profile showing depth (meters, relative to instantaneous sea level) along the y-axis (left margin) and UTC time along the profile (labeled at 5-minute intervals), with a color bar scale for Sv (in dB referenced to 1 inverse meter) along the right margin. Navigation was extracted from all the Simrad raw files using 'Export > Export Navigation GPS to .csv or shapefile from raw files', specifying the all navigation option, and saved as CSV ASCII text.
    2) The python notebook EK80_ESP3NavProc.ipynb utilized Pandas (version 0.25.1) 'read_csv' to import data from the CSV ASCII files into a dataframe containing columns for filename, Pandas datetime (UTC time), latitude, and longitude. Longitude values were converted from positive degrees measured from the zero degree origin to negative values in the western hemisphere (by subtracting 360 degrees), Pandas datetimes were rounded to the nearest second, and new records with navigation coordinates at even one minute datetimes were interpolated between the input time bounds of each filename. The dataframe was recast to produce a new dataframe with columns for longitude (Lon), latitude (Lat), linename (LineName), a combined year and Julian day string (Year_JD), and a combined Julian day and UTC time string (JD_UTC); the last two were produced via the Pandas datetime string function. Additional columns were added to contain survey (Survey_ID), device (Device_ID), and vessel (Vehicle_ID) identifier strings. A subset of the data, maintaining the first, last, and even one minute time records for each filename, was stored in an additional dataframe. The 1-minute interval was chosen for convenient correlation to the 5-minute annotation interval provided along the bottom of the PNG profile images. Pandas 'to_sql' was used to create and populate SQL database tables from the complete and 1-minute subset navigation dataframes within a Spatialite (version 4.3.0) enabled SQLite (version 3.3.0) database. The resulting database columns for each table consist of Lon, Lat (WGS84 dd), LineName, Year_JD, JD_UTC (DDD:HH:MM:SS), SurveyID, VehicleID, and DeviceID. SQLite operations created ('AddGeometryColumn') and populated ('Update') point geometry columns in each of the new tables from the navigation coordinates. A third database table was created with a line string geometry column ('Create Table' and 'AddGeometryColumn') to contain tracklines generated ('Insert') from the complete set of input navigation point geometries for each line (sorted by LineName and UTC Time), and the line length in kilometers was calculated. The trackline database table was updated to include columns for the year and Julian day and Julian day and time of the first and last (YJD_inti, JDUTC_init, YJD_end, and JDUTC_end) navigation records for each filename. The resulting database columns of the line geometry table consist of LineName, YJD_init, JDUTC_init, YJD_end, JDUTC_end, SurveyID, VehicleID, DeviceID, and Length_km.
    These process steps and all subsequent process steps were conducted by the same person - Wayne Baldwin. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Wayne E. Baldwin
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2226 (voice)
    (508) 457-2310 (FAX)
    wbaldwin@usgs.gov
    Date: Dec-2020 (process 2 of 2)
    PROCESS STEP 2: The EK80 1-minute navigation points and trackline features were added (Add Data) into ArcGIS Pro (version 2.3.3) from the SQLite database, then exported (using the Feature Class to Feature Class geoprocessing tool) to the new Esri polyline shapefiles '2018-002-FA_EK80NavPoints_1min.shp' and '2018-002-FA_EK80Tracklines.shp'. The field 'EK80_Image' was added (Add Field) to the attribute table of '2018-002-FA_EK80Tracklines.shp' and manually populated by entering the name of the PNG profile image encompassing the time period for each raw filename.
  3. What similar or related data should the user be aware of?
    Baldwin, Wayne, Foster, David, Bergeron, Emile, Ferro, Peter Dal, McKee, Jennifer, Moore, Eric, Nichols, Alex, O'Brien, Thomas, Powers, Dan, Miller, Nathaniel, and Ruppel, Carolyn, 2020, Multichannel Seismic-Reflection and Navigation Data Collected Using Sercel GI Guns and Geometrics GeoEel Digital Streamers During the Mid-Atlantic Resource Imaging Experiment (MATRIX), USGS Field Activity 2018-002-FA: data release DOI:10.5066/P91WP1RZ, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Baldwin, W.E., Foster, D.S., Bergeron, E.M., Dal Ferro, P., McKee, J.A., Moore, E.M., Nichols, A.R., O'Brien, T.F., Powers, D., Miller, N.C., and Ruppel, C.D., 2020, Multichannel seismic-reflection and navigation data collected using Sercel GI guns and Geometrics GeoEel digital streamers during the Mid-Atlantic Resource Imaging Experiment (MATRIX), USGS field activity 2018-002-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P91WP1RZ.

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 Simrad ES38-10 split-beam transducer was mounted in a frame placed inside the retractable keel of the R/V Hugh R. Sharp, which is located approximately amidships on the center line of the vessel. During 2018-002-FA the frame and transducer were mounted in the rear slot of the retractable keel. Navigation for the EK80 was collected using a Wide Area Augmentation System (WAAS) enabled Hemisphere R131 Differential GPS (DGPS) receiver with the navigational reference point (NRP) antenna mounted on the aft 01 deck handrail approximately 3.4 meters aft of the ES38-10 transducer. Positioning data were recorded as raw NMEA messages to the Simrad raw files in the Simrad EK80 (version 1.12.2.0) acquisition software. GPS horizontal positional accuracy is assumed to be within 3 m; horizontal offsets of the transducer relative to the GPS antenna were not accounted for during processing.
  3. How accurate are the heights or depths?
    A constant sound speed of 1536.3 meters per second was used in the Simrad EK80 (version 1.12.2.0) acquisition and ESP3 (version 1.8.1) processing software packages to convert two-way travel times to water depths. Water depths indicated on the vertical axis of the PNG profile images are referenced to instantaneous sea level, no corrections for ship motion (heave, pitch, roll) or tides have been applied. While no direct assessment of vertical accuracy has been conducted, we conservatively estimate that processed data are accurate to within 1% of the water depth.
  4. Where are the gaps in the data? What is missing?
    EK80 data were collected over two continuous legs that extended August 8-18 and August 19-28, 2018. All data collected during the cruise are represented in these data release files, with the exception of those collected during the system calibration and testing conducted Aug. 8 (JD220) 17:47 through Aug. 9 (JD221) 01:03 UTC, as well as Aug. 28 (JD240) between 12:11 and 12:43 UTC when data were recorded but without navigation due to serial connection problems (no trackline exists for this file in '2018-002-FA_MCS_cmpTracklines.shp' but data for this time period are included in '2018-002-FA_-D20180828-T104720.raw...2018-002-FA_-D20180828-T121157.raw.png). Survey was halted for returns to port Aug. 18 (JD230) 00:41 through Aug. 19 (JD231) 16:14 UTC for refueling and Aug. 22 (JD234) 06:14 and Aug 23 (JD235) 00:06 UTC due to inclement weather. Data were also not collected Aug. 23 (JD235) 05:06 - 11:45 UTC during deployment of the multichannel seismic gear and Aug. 16 (JD228) between 01:39 and 02:26 UTC during an interruption in the ships power. PNG images were not produced for some trackline sections where EK80 data was recorded, but the files were unable to be imported into the ESP3 software; in these cases 'no image available' is entered in the 'EK80_Image' field of '2018-002-FA_MCS_cmpTracklines.shp'.
  5. How consistent are the relationships among the observations, including topology?
    Raw file start times indicated by the last six digits of 'LineName' in '2018-002-FA_EK80Tracklines.shp' and '2018-002-FA_EK80NavPoints_1min.shp' lag between 2 and 7 seconds behind corresponding start times indicated by 'JDUTC_init' in '2018-002-FA_EK80Tracklines.shp' and 'JD_UTC' for the first point record of each file in '2018-002-FA_EK80NavPoints_1min.shp'. This inconsistency stems from utilizing an automatic file change function based on file size limit during acquisition, which resulted in raw files containing a time range of NMEA GPS navigation messages spanning from the second ping of the file to several seconds beyond the start of the subsequent file. The 'LineName' for each polyline feature in '2018-002-FA_EK80Tracklines.shp' matches the prefix name of the corresponding Simrad raw (*.raw) acquisition file. The 'EK80_Image' attribute field corresponds to the PNG profile images in '2018-002-FA_EK80_Images.zip'. In some instances one PNG image exists per raw file, in others PNG images represent the concatenation of multiple raw files. In the case of the later, the name of the PNG image indicates the file range included, eg. the image '2018-002-FA_-D20180809-T010303.raw...2018-002-FA_-D20180809-T020751.raw.png' includes all files between times D20180809-T010303 and D20180809-T020751. As such, a single PNG file can be paired with multiple raw files ('LineName') in '2018-002-FA_EK80Tracklines.shp'. The Simrad raw data were converted to PNG format for ease of display. At some points during surveying, acquisition setting changes caused the sample rate of the system to change mid file, an issue which the processing software does not handle properly. As a result, some images contain time periods (mostly toward the end of the files) in which the depth scale is incorrect for data after the sample rate change. These instances are easily recognizable and occur in the following image files: 2018-002-FA_-D20180813-T092858.raw.png, 2018-002-FA_-D20180813-T152001.raw...2018-002-FA_-D20180813-T160055.raw.png, 2018-002-FA_-D20180813-T184840.raw...2018-002-FA_-D20180813-T210511.raw.png, 2018-002-FA_-D20180814-T003330.raw...2018-002-FA_-D20180814-T010923.raw.png, 2018-002-FA_-D20180814-T013421.raw.png, 2018-002-FA_-D20180814-T053926.raw...2018-002-FA_-D20180814-T073126.raw.png, 2018-002-FA_-D20180814-T074421.raw...2018-002-FA_-D20180814-T092921.raw.png, 2018-002-FA_-D20180814-T095822.raw...2018-002-FA_-D20180814-T104310.raw.png, 2018-002-FA_-D20180814-T212344.raw.png, 2018-002-FA_-D20180816-T234125.raw.png, 2018-002-FA_-D20180817-T042357.raw.png, 2018-002-FA_-D20180817-T053517.raw.png, 2018-002-FA_-D20180817-T093116.raw.png, 2018-002-FA_-D20180817-T153926.raw...2018-002-FA_-D20180817-T181627.raw.png, 2018-002-FA_-D20180820-T200257.raw...2018-002-FA_-D20180820-T211427.raw.png, 2018-002-FA_-D20180822-T025003.raw.png, 2018-002-FA_-D20180822-T041139.raw.png, 2018-002-FA_-D20180822-T043538.raw...2018-002-FA_-D20180822-T052129.raw.png, 2018-002-FA_-D20180823-T125001.raw...2018-002-FA_-D20180823-T143704.raw.png. Data acquired between Aug. 9 (JD221) 06:10 and Aug. 10 (JD222) 14:20 UTC, during the transit between the calibration site and the site of MCS equipment deployment, only extend to 2400 meters water depth, and did not capture the entire water column including the seafloor.

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 distributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the data set.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? USGS data release of EK80 split-beam echo sounder data collected during the Mid-Atlantic Resource Imaging Experiment (MATRIX), USGS field activity 2018-002-FA: includes '2018-002-FA_EK80NavPoints_1min.shp' containing navigation fixes for the start, end, and even 1-minute time intervals for each file, '2018-002-FA_EK80Tracklines.shp' containing trackline features, '2018-002-FA_EK80_Images.zip' containing 183 PNG images, the browse graphic '2018-002-FA_EK80BrowseImage.jpg', and the Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file '2018-002-FA_EK80_meta.xml'. These datasets can be downloaded individually or packaged on-demand in a zip file (see the Digital Transfer Option section).
  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. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), and have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product 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?
    To utilize these data, the user must have software capable of reading shapefiles and PNG images.

Who wrote the metadata?

Dates:
Last modified: 15-Jan-2021
Metadata author:
U.S. Geological Survey
Attn: Wayne E. Baldwin
Geologist
384 Woods Hole Rd.
Woods Hole, MA

(508) 548-8700 x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P948VJ4X/2018-002-FA_EK80_meta.faq.html>
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