5-meter bathymetric data collected in 2014 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (32-bit GeoTIFF, UTM Zone 18N, WGS 84)

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Frequently anticipated questions:


What does this data set describe?

Title:
5-meter bathymetric data collected in 2014 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (32-bit GeoTIFF, UTM Zone 18N, WGS 84)
Abstract:
The Delmarva Peninsula is a 220-kilometer-long headland, spit, and barrier island complex that was significantly affected by Hurricane Sandy. A U.S. Geological Survey cruise was conducted in the summer of 2014 to map the inner continental shelf of the Delmarva Peninsula using geophysical and sampling techniques to define the geologic framework that governs coastal system evolution at storm-event and longer timescales. Data collected during the 2014 cruise include swath bathymetry, sidescan sonar, chirp and boomer seismic-reflection profiles, acoustic Doppler current profiler, and sample and bottom photograph data. Processed data in raster and vector format are released here for the swath bathymetry, sidescan sonar, and seismic-reflection profiles. More information about the USGS survey conducted as part of the Hurricane Sandy Response-- Geologic Framework and Coastal Vulnerability Study can be found at the project website or on the WHCMSC Field Activity Web pages: https://woodshole.er.usgs.gov/project-pages/delmarva/ and https://cmgds.marine.usgs.gov/fan_info.php?fan=2014-002-FA
  1. How might this data set be cited?
    U.S. Geological Survey, 2015, 5-meter bathymetric data collected in 2014 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (32-bit GeoTIFF, UTM Zone 18N, WGS 84): data release DOI:10.5066/F7MW2F60, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Pendleton, E.A., Ackerman, S.D., Baldwin, W.E., Danforth, W.W., Foster, D.S., Thieler, E.R., and Brothers, L.L., 2015, High-resolution geophysical data collected along the Delmarva Peninsula 2014, U.S. Geological Survey Field Activity 2014-002-FA: data release DOI:10.5066/F7MW2F60, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.6031379955789
    East_Bounding_Coordinate: -74.65660495738244
    North_Bounding_Coordinate: 38.465827972474074
    South_Bounding_Coordinate: 37.526953449184454
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2014-002-FA/data/bathymetry/Delmarva_bathy.png (png)
    thumbnail image of uninterpolated bathymetric data for the Delmarva Peninsula
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 18-Jun-2014
    Ending_Date: 22-Jul-2014
    Currentness_Reference:
    ground condition; data were not collected on 20140702-20140704; 20140709; 20140714-20140715 due to weather
  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, type Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 18 N
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -75
      Latitude_of_Projection_Origin: 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 5
      Ordinates (y-coordinates) are specified to the nearest 5
      Planar coordinates are specified in meters
      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.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Mean lower low water
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    There are no attributes associated with a GeoTIFF. The "no data" value is set to 3.402823e+038
    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?
    U.S. Geological Survey
  3. To whom should users address questions about the data?
    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA

    (508) 548-8700x2259 (voice)
    (508)-457-2310 (FAX)
    ependleton@usgs.gov

Why was the data set created?

This 5-m uninterpolated bathymetric grid was created from swath interferometric bathymetry data. Bathymetric data are useful geophysical datasets for geologic framework studies. These data can be used in conjunction with other geophysical and sample data to identifying sea-floor morphology and sediment texture.

How was the data set created?

  1. From what previous works were the data drawn?
    raw bathymetry (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, raw interferometric data in sxr format.

    Type_of_Source_Media: disc
    Source_Contribution:
    USGS used a 234 kHz Systems Engineering and Assessment Ltd. (SEA) SWATHplus interferometric sonar (now BathySwath) mounted on the port side of the M/V Scarlett Isabella.
    Survey lines were run at an average speed of 5 knots and were spaced 200 m apart in the nearshore to approximately 3-km apart in the offshore. Full data coverage was obtained for sidescan sonar data, but not for bathymetric data. The SEA SWATHplus-M (BathySwath-1) operates at a frequency of 234 kHz and a variable range (increased or decreased manually depending on water depth, but generally 85 m on both sides). The system was operated with a transmit power of 80 percent, a transmit length of 43 cycles, and 4096 samples per channel. Sound-velocity profiles were collected continuously with an ODIM MVP30 moving vessel profiler. Tides were corrected using a zone tidal model with observed tides from gauges in Atlantic City, NJ; Lewes, DE; Chesapeake Bay-Bridge-Tunnel, VA; and Duck, NC.
  2. How were the data generated, processed, and modified?
    Date: 30-Jul-2014 (process 1 of 6)
    Each raw BathySwath bathymetric sonar file (sxr) was converted to a processed file (sxp) using BathySwath Processor (vers. 3.10.0.2; this new version allows the import of nearly an unlimited number of sound velocity profiles. This makes the process of recreating sxp files much easier if the data need reprocessing - which they did for this survey). During the conversion process, sound velocity profiles were used to minimize potential refraction artifacts from fluctuations in the speed of sound within the water column. Several bathymetric filters were applied to remove erroneous soundings and reduce the density of the data. Observed tidal corrections were applied later in the processing flow after observed tides were released from NOAA's Tides and Currents website, which is typically a 2-4 week lag. Bathymetric filtering typically included low amplitude (100%), range (0-4m), box (3-50m depth, 1.5-75m horizontal), median (window size 5), alongtrack 1 (depth difference of 5-m, window size 5-m, and learn rate of 0.7), alongtrack 2 (depth difference of 1.5-m, window size 1m, and learn rate of 0.9), and mean filters (0.25m). These represent the typical parameters used for the majority of the USGS surveys although the values may have been adjusted slightly for specific parts of the survey area. Person who carried out this activity:
    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    (508) 548-8700x2259 (voice)
    (508)-457-2310 (FAX)
    ependleton@usgs.gov
    Date: 30-Jul-2014 (process 2 of 6)
    A new CARIS HIPS project (vers. 9.0.6) was created with projection information set to Universal Transverse Mercator (UTM) Zone 18, WGS84. Each BathySwath reprocessed file (sxp) was imported to the new CARIS project using the Import/Conversion Wizard. A 5 meter resolution Bathymetric and Statistical Error (BASE) Surface was created from the files for each Julian day. The BASE surface for each day was reviewed for any inconsistencies or data anomalies. Navigation was reviewed and edited as needed using the navigation editor tool. Beam-to-beam slopes and across track angle filters were applied to the soundings line by line. The refraction editor was used to adjust sound speed values in areas where velocimeter data did not adequately correct depth profiles obviously influenced by local anomalies in speed of sound through the water column. Person who carried out this activity:
    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    (508)-548-8700x2259 (voice)
    (508)-457-2310 (FAX)
    ependleton@usgs.gov
    Date: 28-Mar-2015 (process 3 of 6)
    Within CARIS (version 9.0.6) tide corrections (to MLLW) were applied using a discrete tidal-zoning model (DTZ) developed by NOAA/NOS's Hydrographic Planning Team (Huang, personal communication, 2010) (<http://www.tidesandcurrents.noaa.gov/hydro.html>). The DTZ model corrects differences in tidal phase and amplitude between the survey area and observations made at NOS tide gauges at Atlantic City, NJ(8534720), Lewes, DE (8557380), Chesapeake Bay-Bridge-Tunnel, VA (8638863) and Duck NC (8651370). The tidal zone model was imported into CARIS (version: HIPS and SIPS 9.0.6) as a zone definition file (ZDF) and the tide gauge data were loaded as caris .tid format files. Following tide correction, each line was re-merged and a BASE surface for the entire survey areas was computed to incorporate the MLLW verified tide information. Additional swath editing was done in CARIS using the swath and area based editors to remove additional inconsistencies and minimize survey artifacts. The CARIS HIPS BASE surface was exported from CARIS as a Bathymetry Attributed Grid (BAG) file and then imported into ArcMap version 10.2. This creates an Esri Grid format file with 3 separate file folders. To avoid this cumbersome translation from BAG to Esri format, the data were converted to a 32-bit GeoTIFF using DEFLATE compression for transfer purposes. Also within ArcMap a .tfw file was created using the export raster world file tool. Although the processing steps described here are very similar to the processing steps described in version 1 of this dataset. This grid represents a more finalized version including refraction editing, swath editing, and stricter depth filtering. This version should be used instead of version 1. Person who carried out this activity:
    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    508-548-8700 x2259 (voice)
    508-457-2310 (FAX)
    ependleton@usgs.gov
    Date: 18-Apr-2017 (process 4 of 6)
    The online links to the data were updated to reflect the new server hosting the data. Additionally, other small edits could be made to the metadata, such as modifying http to https where appropriate. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 5 of 6)
    USGS Thesaurus keywords added to the keyword section. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 6 of 6)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?

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

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    Navigation was acquired with a Coda Octopus F185 Differential Global Positioning System + Wide Area Augmentation System (DGPS+WAAS), which is accurate to + or - 1 to 2 meters, horizontally and RTK positioning from an Ashtech Proflex 800, which is accurate to less than 1-meter, horizontally. X,Y data are referenced to WGS84. The SWATHPlus transducers were mounted on a rigid pole, approximately 4.195 m below the water line, along the port side of the M/V Scarlett Isabella. The DGPS antenna and an Ashtech ProFlex 800 RTK GPS were located on the same pole approximately 4.6m above the sea surface. RTCM corrections were being delivered via the web (ethernet) to the Ashtech ProFlex 800 from shore stations in MD and VA (ethernet satellite link is from a KVH Mini-VSAT Broadband receiver). The RTK corrections were passed through to the F185R giving the submetrix system kinematic (x,y) positioning accuracy from Julian Day 170 and later. Lines (l1f1-l7f1) collected prior to 20140719 at 12:40:00 UTC were recorded with WAAS-enabled DGPS because the F185 was not receiving RTCM corrections from the Ashtech ProFlex800. Positional offsets from antennae to MRU were corrected within the SWATHPlus acquisition software.
    WAAS enabled DGPS accuracy is estimated to be less than 3 m and the accuracy of RTK-GPS is estimated to be less than 1 m.
  3. How accurate are the heights or depths?
    Vertical accuracy of the raw data based on system specifications may approximate 1% of water depth, 0.1 to 0.4 meters within the survey area. However, overall vertical accuracies on the order of 50-cm or better are assumed based on the following considerations: The Coda Octopus F185 Attitude and Positioning system, used to correct for vessel roll, pitch, heave, and yaw, has a theoretical vertical accuracy of a few mm. Tidal offsets were corrected to MLLW using a Zone Tidal Model supplied by the Hydrographic Planning Team at NOAA's National Ocean Service. Zone Tidal Models must conform to IHO standards which is within 30-cm vertical accuracy. Refraction artifacts were minimized by acquiring numerous sound velocity profiles (greater than 500) with a Brooke Ocean MVP30 moving vessel profiler. Sound velocity data are entered into the SWATHPlus acquisition software to model the sound velocity structure of the water column. Gridding algorithms and cell sizes for these data could introduce errors as great as 3m along the edges of the data, but gridding-induced errors are likely much smaller (less than 20cm) for most of the survey area. Changes in ship draft due to water and fuel usage were not considered.
  4. Where are the gaps in the data? What is missing?
    Survey line bathymetry data that were collected within the Delmarva survey area were incorporated in this grid with the exception of the lines listed below. These lines were left out of the final grid either because the data quality were poor, the lines were duplicated or superceded by another line of better data quality, the line was a jog around a shoal and was redundant, or their contribution to the final product was not significant. l2f5, l5f3, l7f4,l7f5,l19f1-l19f5,l20f3-l20f8,l26f1,l28f1,l30f1,l31f1,l33f1,l35f1,l37f1, l41f1, l43f1, l50f10, l51f1-l5f4, l52f1-l52f2, l100f1-l100f3,l96f1,l103f3,l155f2, l163f3, and t1f1-t13f1.
  5. How consistent are the relationships among the observations, including topology?
    This grid represents uninterpolated swath interferometric bathymetry data at 5.0 meter resolution. Quality control and data processing were conducted to remove spurious points and reduce speed of sound artifacts (refraction). Soundings from the surveys were processed and edited using Computer Aided Resource Information System (CARIS) Hydrographic Information Processing System (HIPS; ver. 9.0.6). Although the soundings were edited, small data spikes may still exist.

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:
Not to be used for navigation. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
  1. Who distributes the data set? (Distributor 1 of 1)
    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@usgs.gov
  2. What's the catalog number I need to order this data set? USGS data release 2014-002-FA bathymetry from the Delmarva Peninsula area (2014-002-FA_bathy.zip). The zip file contains a folder with the following 32-bit GeoTIFF image (2014-002-FA_5m_MLLW.tif) with a world file (2014-002-FA_5m_MLLW.tfw). A browse graphic (Delmarva_bathy.png) and FGDC CSDGM metadata files (2014-002-FA_5m_MLLW.tif.xml) in four standard formats are also included in the zip file.
  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. Is there some other way to get the data?
    none
  6. What hardware or software do I need in order to use the data set?
    The ZIP file contains a 32-bit GeoTIFF image compressed using the DEFLATE compression format with a world file. To utilize these data an image processing or GIS software package capable of importing a 32-bit TIFF image with DEFLATE compression. Standard image viewing software cannot translate a 32-bit image.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
Elizabeth A. Pendleton
U.S. Geological Survey
Geologist
U.S. Geological Survey
Woods Hole, MA
USA

508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@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/field_activities/2014_002_fa/2014-002-FA_5m_MLLWbathy.faq.html>
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