Breton2014_IFB_SBB_100_NAD83_NAVD88_UTM16N_GEOID09_DEM: A geotiff of the 100-meter cell size digital elevation model derived from the processed interferometric swath, single beam bathymetry, and Lidar data points.

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:

What does this data set describe?

Title:
Breton2014_IFB_SBB_100_NAD83_NAVD88_UTM16N_GEOID09_DEM: A geotiff of the 100-meter cell size digital elevation model derived from the processed interferometric swath, single beam bathymetry, and Lidar data points.
Abstract:
As part of the Barrier Island Monitoring Project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted nearshore geophysical surveys off Breton and Gosier Islands, Louisiana, in July and August of 2014. To assist the United States Fish and Wildlife Service (USFWS) with restoration planning efforts, the USGS was tasked with answering fundamental questions about the physical environment of the southern Chandeleur Islands, including the geology, morphology, and oceanography. Baseline data needed to answer these questions was either insufficient or missing in the area. The USGS conducted a comprehensive geologic investigation in the summer of 2014 by collecting geophysical and sedimentological data. Breton Island, located at the southern end of the Chandeleur Island chain, Louisiana, was recognized as a natural and globally important nesting sanctuary for several bird species and was established as the Breton National Wildlife Refuge (NWR) in 1904. The aerial extent of Breton Island has diminished 90% since 1920. Land loss is attributed to ongoing relative sea-level rise, diminished sediment supply, and storm impacts. The bird population on Breton Island has also declined over the years, most notably after Hurricane George in 1998 and Hurricane Katrina in 2015, which completely submerged the island. Despite the decreasing habitable acreage, migratory seabirds continue to return and utilize Breton Island. To prevent the island from being completely submerged in the future and to protect, stabilize, and provide more nesting and foraging areas for the birding population, the USFWS is proposing a restoration effort to rebuild Breton Island to its pre-Katrina footprint. This Data Series serves as an archive of processed interferometric-swath, single-beam bathymetry, and side-scan sonar data collected in the nearshore of Breton and Gosier Islands, NWR, Louisiana. The data were collected during two USGS cruises (USGS Field Activity Numbers 2014-314-FA and 2014-317-FA) in July and August 2014. Geographic Information System data products include a 100 meter-cell-size interpolated bathymetry grid surface, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee (FGDC) metadata.
Supplemental_Information:
The interferometric swath bathymetry navigation data was acquired with Marinestar High Precision Differential Geographic Positioning System (DGPS),which used the ITRF2005 datum. For the single-beam bathymetry, the differential positioning was obtained through post-processing the base station data to the rover data. All datasets were transformed from their initial datums (ITRF00 for SBB and ITRF05 for IFB) to NAD83 using GEOID09 (NOAA NGS VDatum software version 3.2 - http://vdatum.noaa.gov/). The final x,y,z position data was gridded at a 100-meter cell size resolution to create the digital elevation model.
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, Breton2014_IFB_SBB_100_NAD83_NAVD88_UTM16N_GEOID09_DEM: A geotiff of the 100-meter cell size digital elevation model derived from the processed interferometric swath, single beam bathymetry, and Lidar data points.:.

    Online Links:

    This is part of the following larger work.

    DeWitt, Nancy T., Fredericks, Jake J., Flocks, James G., Miselis, Jennifer L., Locker, Stanley D., Kindinger, Jack L., Bernier, Julie C., Kelso, Kyle W., Reynolds, B.J., Wiese, Dana S., and Browning, Trevor, 2015, Archive of bathymetry and backscatter data collected in 2014 nearshore Breton and Gosier Islands, Breton National Wildlife Refuge, Louisiana.: U.S. Geological Survey Data Series 1005, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.303995
    East_Bounding_Coordinate: -89.013844
    North_Bounding_Coordinate: 29.598653
    South_Bounding_Coordinate: 29.371525
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2014
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 247 x 277 x 1, type Grid Cell
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -87.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 100
      Ordinates (y-coordinates) are specified to the nearest 100
      Planar coordinates are specified in meter
      The horizontal datum used is D North American 1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: North American Vertical Datum 1988 (NAVD88)
      Depth_Resolution: 0.001
      Depth_Distance_Units: meter
      Depth_Encoding_Method: Implicit coordinate
  7. How does the data set describe geographic features?

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?
    Funds for this report are part of project funds for the Louisiana Outer Coast Early Restoration Project, obtained by the natural resource trustees for the Deepwater Horizon Oil Spill, pursuant to the Framework for Early Restoration Addressing Injuries Resulting from the Deepwater Horizon Oil Spill executed April 20, 2011. USFWS is the project lead for the North Breton Island Barrier Island Restoration project. Acknowledgment of the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices. Sharing of new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such.
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov

Why was the data set created?

This 100-meter cell size digital elevation model is an interpretive product that was derived from the processed interferometric swath, single-beam bathymetry, and Lidar data collected in July and August 2014, around the southern Chandeleur Islands, Louisiana.

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: 2014 (process 1 of 9)
    GPS Acquisition: A GPS base station was erected at a temporarily installed USGS benchmark (BRET) located on the sound side of the Chandeleur Islands. A second base station (BRT2) was temporarily installed on top of a short piling located approximately 0.40 km southwest of the BRET base location to provide a backup base station. GPS receivers recorded the 12-channel full-carrier-phase positioning signals (L1/L2) from satellites via the Thales choke-ring antenna at the base stations. A similar GPS instrument combination was duplicated on the survey vessel (rover). The base receivers and the rover receivers recorded their positions concurrently at the same time intervals (1.0-second(s) for 14BIM02 and 0.1-s for 14BIM03) throughout the survey. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2014 (process 2 of 9)
    Single-Beam Bathymetry Acquisition: The single-beam bathymetric data were collected aboard the 22-foot R/V Jabba Jaw and a 15 ft Personal Water Craft (PWC) R/V Chum Bucket. Boat motion was recorded at 50-millisecond (ms) intervals using a Teledyne TSS Dynamic Motion Sensor (TSS DMS-05). HYPACK version 14.0.9.47, a marine surveying, positioning, and navigation software package, managed the planned-transect information and provided real-time navigation, steering, correction, data quality, and instrumentation-status information to the boat operator. Depth soundings were recorded at 50-ms intervals using an Odom echotrac CV100 sounder with a 200-kilohertz (kHz) transducer. Data from the GPS receiver, motion sensor, and fathometer were recorded in real-time and merged into a single raw data file (.raw) in HYPACK, with each device string referenced by a device identification code and time stamped to UTC. Sound velocity profile (SVP) measurements were collected using a SonTek Castaway Conductivity, Temperature, and Depth (CTD) instrument. The instrument was periodically cast overboard to observe changes in water column speed of sound (SOS). The recorded profiles were later incorporated during post-processing to correct the depth for temporal and spatial SOS changes throughout the water column. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2014 (process 3 of 9)
    Swath Bathymetry Acquisition: The interferometric swath bathymetry data were collected aboard the R/V Sallenger in July 2014 and the R/V Tommy Munro in August 2014, using the SEA SWATHplus-H 468 kHz interferometric sonar system. The system was fastened to a static pole mount with the sonar transducer in line with the Novatel GPS antennas sitting atop the mount. Boat position and motion data were recorded in real-time using a CodaOctopus F190R wetpod inertial measurement unit (IMU) mounted underwater, between the transducer heads, to minimize lever arm geometry errors between the observed depths and associated vessel motion. Real-time corrected positions were acquired via Marinestar HP (High-Precision differential global navigation satellite system) differential subscription service from Fugro, Inc. Marinestar HP position correction data and motion data from the IMU were integrated with interferometric soundings in the SWATHplus software version 3.10.2.0 with positional and calibration offsets pre-defined by a session file (.sxs), allowing for real-time-corrected depths. Before deployment, all equipment offsets were measured. During the survey, all swath tracklines were recorded in SWATHplus raw data format (.sxr). A Valeport Mini Sound Velocity Sensor (miniSVS) was attached to the transducer mount and collected continuous SOS measurements at the depth of the transducers. These values were directly read and incorporated into the SWATHplus raw data format during acquisition providing a real-time speed of sound measurement at the transducer, while underway. In addition, a separate Mini Sound Velocity Profiler (Valeport miniSVP) was used to collect speed of sound profiles (water surface to seafloor) at intervals throughout the survey. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2014 (process 4 of 9)
    Differentially Corrected Navigation Processing: The coordinate values of the GPS base station (BRET and BRT2) are the time-weighted average of values obtained from the National Geodetic Survey On-Line Positioning User Service (OPUS). The base station coordinates were imported into GrafNav version 8.5 (Waypoint Product Group) and the kinematic GPS data from the survey vessel were post-processed to the concurrent GPS session data at the base stations. During processing, steps were taken to ensure that the trajectories between the base and rover were clean, resulting in fixed positions. By analyzing the graphs, trajectory maps, and processing logs that GrafNav produces for each GPS session, GPS data from satellites flagged by the program as having poor health or satellite time segments that had cycle slips could be excluded, or the satellite elevation mask angle could be adjusted to improve the position solutions. The final, differentially corrected, precise DGPS positions were computed at the respective time intervals of the roving GPS (1.0 s and 0.10 s) and exported in ASCII text format to replace the uncorrected rover positions, recorded during acquisition. The GPS data were processed and exported in the World Geodetic System of 1984 (WGS84)(G1150) geodetic datum. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources produced in this process:
    • Post-processed differential navigation data for the rover (boat), in ASCII text format. Three files (forward, reverse, and combined trajectories) are produced for each GPS session file.
    Date: 2014 (process 5 of 9)
    Single-Beam Bathymetry Processing: All data were processed using CARIS HIPS and SIPS (Hydrographic Information Processing System and Sonar Information Processing System) version 8.1.7. The raw HYPACK (version 13.0.9.17 for 14BIM03 and 14.0.9.47 for 14BIM02) data files were imported into CARIS, the differentially corrected navigation files were imported using the generic data parser tool within CARIS, and any SVP profile casts were entered and edited using the SVP editor within CARIS. The bathymetric data components (position, motion, depth, and SOS) were then merged and geometrically corrected in CARIS to produce processed x,y,z data. Next, the data were edited for outliers and then further reviewed in the Subset Editor utility for crossing status, and questionable data points or areas. The geometrically corrected point data were then exported as an x,y,z ASCII text file, referenced to WGS84 (G1150), equivalent to ITRF00; ellipsoid height is presented in meters. An in house naming convention for the source files used and source files produced in this process step contain the symbols “xxx” which is a placeholder for a the naming schema. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources used in this process:
    • Post-processed differential navigation data and raw HYPACK bathymetric data in ASCII text format.
    Data sources produced in this process:
    • 14BIM02_SBB_ITRF00_03_xxx.txt and 14BIM03_SBB_ITRF00_03_xxx.txt
    Date: 2014 (process 6 of 9)
    Swath Bathymetry Processing: The interferometric swath bathymetry data were collected aboard the R/V Sallenger and the R/V Tommy Munro using a 468 kHz Systems Engineering and Assessment Ltd. (SEA), SWATHplus-H (high frequency) interferometric sonar system. SWATHplus serves as both an acquisition software and initial processing software package. Preliminary roll calibration trackline data were collected and processed using SEA SWATHplus version 3.10.2.0 and Grid Processor software version 3.10.0.0. Instrument offsets and calibration values were input into the session file (.sxs), and the raw data files (.sxr) were then processed using the updated system configuration containing roll calibration values, measured equipment offsets, acquisition parameters, navigation and motion from the F190R, SOS at the sonar head, and SVP cast data. Any calibration offsets and acoustic filtering utilized in SWATHplus is then applied to each raw data file to create a processed data file (.sxp), which was then imported into advanced sounding data processing software CARIS HIPS and SIPS® version 8.1. The initial real-time processing datum for the swath and backscatter data was ITRF05, which is the acquisition datum for Marinestar HP position and navigation data. All processed data files (.sxp) were imported into CARIS HIPS and SIPS® version 8.1. Outliers for the navigation data and processed soundings were removed using program filters. Any remaining data outliers were then edited out manually. A CARIS Bathymetry with Associated Statistical Error (BASE) surface with associated Combined Uncertainty and Bathymetry Estimator (CUBE) sample surface was created from the edited soundings. A CUBE hypothesis is the estimated value of a grid node representing all the soundings within a chosen resolution or grid-cell size (for example, 5 m) weighted by uncertainty and proximity, giving the final value as a "sample" of the data within the specific grid cell. This algorithm allows for multiple grid-node hypotheses to be verified or overridden by the user while maximizing processing efficiency. A 5-m resolution CUBE surface was created to perform initial hypothesis editing using the CARIS Subset Editor tool, followed by higher resolution surface detail editing within subset editor. The sample x,y,z data were exported as an ASCII text file, at a 5-m x 5-m sample resolution in the ellipsoid datum of ITRF05. The data were then transformed into NAD83 and NAVD88 (GEOID09) using VDatum version 3.2. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources produced in this process:
    • 14BIM01_IFB_04_5m_ITRF05.txt and 14BIM05_IFB_04_5m_ITRF05.txt
    Date: 2014 (process 7 of 9)
    Datum Transformation: Using the transformation software VDatum version 3.2, the interferometric swath bathymetric data were transformed horizontally from their data acquisition datum (ITRF05 for the IFB and ITRF00 for the SBB) to the North American Datum of 1983 (NAD83) reference frame using the National Geodetic Survey (NGS) geoid model of 2009 (GEOID09). An in-house naming convention for the source files used and source files produced in this process step contain the symbols “xxx” which is a placeholder for a the naming schema. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources used in this process:
    • 14BIM01_IFB_LEVEL_04_XXX_ITRF05.txt 14BIM02_SBB_Level_03_xxx_ITRF00.txt 14BIM03_SBB_Level_03_xxx_ITRF00.txt 14BIM05_IFB_Level_04_xxx_ITRF05.txt
    Data sources produced in this process:
    • 14BIM01_IFB_04_5m_NAD83_NAVD88_GEOID09.txt 14BIM02_SBB_04_NAD83_NAVD88_GEOID09.txt 14BIM03_SBB_04_NAD83_NAVD88_GEOID09.txt 14BIM05_IFB_04_5m_NAD83_NAVD88_GEOID09.txt
    Date: 2015 (process 8 of 9)
    Gridding Bathymetric Data: An encompassing digital elevation model (DEM) was created using the soundings from the individual platforms (R/V Sallenger--IFB, R/V Tommy Munro--IFB, R/V Jabba Jaw--SBB, and R/V Chum Bucket--SBB) and lidar data collected in 2014. A running mean of 2 m was applied to each dataset using the open-source software package, Generic Mapping Tools (GMT), version 4.5 blockmean filter to avoid aliasing short wavelengths (Wessel and others 1994). Since the shallow water data collected by the jet skis overlapped the water depth measurements from the topobathy lidar survey, the two data files were merged, and a blockmean filter was applied to the merged data. The data was first sorted by geographic position so that the blockmean filter would prioritize by position rather than acquisition platform. The resulting data file was then gridded into 100 m grid cells, using the GMT Tools surface algorithm with a search radius of 200 m to initialize the grid, and a tension filter of 0.03 to suppress spurious oscillations. A grid mask generated from a polygon digitized around the survey area was applied to the resulting grid to exclude areas of "no data", using the GMT Tools grdmask and grdmath functions. The grid file in Network Common Data Form (NetCDF) was converted to a raster using Esri’s ArcMap version 10.2.2 Multidimension Tool "Make NetCDF Raster Layer" and exported as a GeoTIFF. Additionally, the DEM was converted into a point file using Esri’s raster to point conversion tool and the easting and northing positions populated using XTools Pro version 11.1. The elevation range for the 2014 Breton Island DEM is +1.53 meters to -10.45 m. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources used in this process:
    • The text files below were used to create the final grid file. The use of "sort" in the file name indicates that the dataset was sorted by position. The "bm2" identifier indicates that the dataset was sent through the Generic Mapping Tools (GMT) version 4.5 blockmean filter. 14BIM_jet_lidar_sort_bm2.txt 14BIM01_Sal_ifb_bm2.txt 14BIM02_twin_sbb_bm2.txt 14BIM03_jet_sbb_bm2.txt 14BIM05_Munro_ifb_bm2.txt 14LGC_lidar_bm2.txt
    Data sources produced in this process:
    • Breton2014_IFB_SBB_10m_NAD83_NAVD88_GEOID09_DEM.tif
    Date: 13-Oct-2020 (process 9 of 9)
    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?
    The accuracy of the data is determined during data collection. The single-beam and interferometric swath bathymetry data were collected during two research cruises, one in July 2014 and the other in August 2014. Methods are employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment (single-beam and swath) is isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements are recorded manually and digitally and entered into their respective programs for calibration. Once calibration is complete and calibration status is considered acceptable, survey operations commence. Each system has a dedicated computer, and efforts are made to utilize the same equipment and software versions on both systems. However, upgrades and changes occur and require additional setup, measurements, and notation. For the single-beam bathymetry, offsets between the single-beam transducers and the Ashtech antenna reference point (ARP) were measured and accounted for in post-processing. Bar checks were performed as a calibration check and accounted for any drift in the echosounder. Differential Global Positioning System (DGPS) coordinates were obtained using post-processing software packages (National Geodetic Survey On-Line Positioning User Service, OPUS, and Waypoint Product Group GrafNav, version 8.5). For the interferometric swath bathymetry, offsets between the sonar head and the DGPS antennas were measured and entered into the CodaOctopus F190R internal setup program. DGPS was provided through the Marinestar High Performance wide-area GPS service by Fugro, Inc. DGPS is always implemented for navigational accuracy either during acquisition or as a post-processing step. These bathymetric data have not been independently verified for accuracy.
  2. How accurate are the geographic locations?
    All static base station sessions were processed through the On-Line Positioning User Service (OPUS) maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS). The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinate (latitude, longitude, and ellipsoid height). Base-station positional error for each GPS session was calculated as the absolute value of the final position minus the session position value. The maximum horizontal error of the base station coordinates used for post-processing the single-beam bathymetry was 0.00060 seconds latitude and 0.00125 seconds longitude for the USGS benchmark, BRET, and 0.00023 seconds latitude and 0.00030 seconds longitude for BRT2. The stated horizontal accuracy of the Marinestar HP navigation subscription used during swath bathymetry acquisition is reported by the service as +/-15 cm (95% of the time).
  3. How accurate are the heights or depths?
    All static base station sessions for BRET and BRT2 were processed through On-Line Positioning User Service (OPUS) maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS). The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinate (latitude, longitude, and ellipsoid height). Base-station positional error for each GPS session was calculated as the absolute value of the final position minus the session position value. SPCMSC standards define the maximum acceptable vertical error for any individual base station GPS session as less than or equal to three times the standard deviation of the ellipsoid height; any occupations exceeding this error are removed and the base station coordinates are recalculated. For the BRET base station location, the standard deviation of the ellipsoid height was 0.014 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.036 m. For the BRT2 base station location, the standard deviation of the ellipsoid height was 0.012 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.029 m. All the processed single-beam bathymetry data (x,y,z) for 2014 are referenced to these base station coordinates. The differentially corrected navigation files (base station GPS processed to boat GPS) were exported from GrafNav version 8.5 and then imported into CARIS HIPS and SIPS version 8.1.7 and merged, by time, with the HYPACK (versions 13.0.9.17 and 14.0.9.47) raw data files at which point the soundings are then geometrically corrected for motion and speed of sound. The vertical accuracy for the SWATHplus-H system varies with depth and across track range. At 57 m it is accurate to 10 cm vertically. Maximum vertical transformation error reported by VDatum is 0.171 m or 17.1 centimeters for eastern Louisiana. The sum of the errors ([+/- 0.013 m] + [+/-0.15 m] +[0.171 m]) in the vertical direction is equal to +/-.334 m or +/- 33.4 cm.
  4. Where are the gaps in the data? What is missing?
    This is a completely processed digital elevation model representing an interpolated bathymetric surface derived from the acoustic interferometric single-beam and swath bathymetry data.
  5. How consistent are the relationships among the observations, including topology?
    The interferometric swath and single beam bathymetry data were collected during two research cruises one in July 2014 and the other in August 2014 (2014-314-FA and 014-317-FA respectively. Refer to the online data series linkage for field logs, vessel platform descriptions, and other survey information available at http://pubs.usgs.gov/ds/1005/ds-logs. The single-beam and interferometric swath bathymetry data were collected during two research cruises, one in July 2014 and the other in August 2014 (2014-314-FA and 2014-317-FA, respectively). These datasets were merged to provide a single post-processed bathymetric digital elevation model (DEM) at 100-meter cell-size resolution. The data gaps between acquisition tracklines are predicted values generated by the gridding algorithm. These bathymetric data have not been independently verified for accuracy.

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 U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data. These data should not be used for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    Attn: Nancy DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@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?
    This publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    The raster contained in the .zip file is available as a GeoTIFF. To utilize this data, the user must have a GIS software package capable of reading the .tif format.

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
U.S. Geological Survey
Attn: Nancy T. DeWitt
Geologist
600 4th Street South
St. Petersburg, FL
USA

727-502-8000 (voice)
ndewitt@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/Breton_2014_IFB_SBB_100_NAD83_NAVD88_UTM16N_GEOID09_DEM_metadata.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:33 2021