Sediment-Texture Units of the Sea Floor for Vineyard and western Nantucket Sounds, Massachusetts (polygon shapefile, Geographic, WGS84)

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Frequently anticipated questions:


What does this data set describe?

Title:
Sediment-Texture Units of the Sea Floor for Vineyard and western Nantucket Sounds, Massachusetts (polygon shapefile, Geographic, WGS84)
Abstract:
Geologic, sediment texture, and physiographic zone maps characterize the sea floor of Vineyard and western Nantucket Sounds, Massachusetts. These maps were derived from interpretations of seismic-reflection profiles, high-resolution bathymetry, acoustic-backscatter intensity, bottom photographs, and surficial sediment samples. The interpretation of the seismic stratigraphy and mapping of glacial and Holocene marine units provided a foundation on which the surficial maps were created. This mapping is a result of a collaborative effort between the U.S. Geological Survey and the Massachusetts Office of Coastal Zone Management to characterize the surface and subsurface geologic framework offshore of Massachusetts.
  1. How might this data set be cited?
    Baldwin, Wayne, 2016, Sediment-Texture Units of the Sea Floor for Vineyard and western Nantucket Sounds, Massachusetts (polygon shapefile, Geographic, WGS84): Open-File Report 2016-1119, 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.

    Baldwin, Wayne E., Foster, David S., Pendleton, Elizabeth A., Barnhardt, Walter A., Schwab, William C., Andrews, Brian D., and Ackerman, Seth D., 2016, Shallow Geology, Sea-Floor Texture, and Physiographic Zones of Vineyard and western Nantucket Sounds, Massachusetts: Open-File Report 2016-1119, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -71.029685
    East_Bounding_Coordinate: -70.430489
    North_Bounding_Coordinate: 41.561614
    South_Bounding_Coordinate: 41.320506
  3. What does it look like?
    http://pubs.usgs.gov/of/2016/1119/GIS_catalog/SedimentTexture/VineyardNantucketSound_sedcover.png (PNG)
    Image of the sediment texture and distribution shapefile for Vineyard and western Nantucket Sounds
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 05-Sep-2001
    Ending_Date: 31-Aug-2011
    Currentness_Reference:
    ground condition of the source data that this interpretation is based on
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (1149)
    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?
    VineyardNantucketSound_sedcover
    Sediment Cover shapefile for Vineyard and western Nantucket Sounds (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.
    sed_type
    Bottom-type classification on the basis of twelve composite units that represent combinations of four end-member units (R= rock; G= gravel; S= sand; M= mud). (Source: Barnhardt and others (1998))
    ValueDefinition
    GThe end-member texture (= or > 90%) Gravel (G) is the primary texture.
    GsThe dominant texture (> 50%) Gravel (G) is given the upper case letter and the subordinate texture (< 50%) sand (s) is given a lower case letter.
    SThe end-member texture (= or > 90%) Sand (S) is the primary texture.
    SgThe dominant texture (> 50%) Sand (S) is given the upper case letter and the subordinate texture (< 50%) gravel (g) is given a lower case letter.
    SmThe dominant texture (> 50%) Sand (S) is given the upper case letter and the subordinate texture (< 50%) mud (m) is given a lower case letter.
    MsThe dominant texture (> 50%) Mud (M) is given the upper case letter and the subordinate texture (< 50%) sand (s) is given a lower case letter.
    RgThe dominant texture (> 50%) Rock (R) is given the upper case letter and the subordinate texture (< 50%) gravel (g) is given a lower case letter.
    RsThe dominant texture (> 50%) Rock (R) is given the upper case letter and the subordinate texture (< 50%) sand (s) is given a lower case letter.
    GrThe dominant texture (> 50%) Gravel (G) is given the upper case letter and the subordinate texture (< 50%) rock (r) is given a lower case letter.
    SrThe dominant texture (> 50%) Sand (S) is given the upper case letter and the subordinate texture (< 50%) rock (r) is given a lower case letter.
    ConfLevel
    Each interpreted polygon was assigned a data interpretation confidence value from 1-5 (more to less confident) on the basis of the quality and number of input data sources. (Source: U.S. Geological Survey)
    ValueDefinition
    1Sediment texture regions that were defined on the basis of the highest resolution bathymetry (10m) and backscatter (1m), bottom photos, sediment samples with laboratory analysis, and seismic interpretations were given the highest data interpretation confidence value of 1.
    2Sediment texture regions that were defined on the basis of the highest resolution bathymetry (10m), backscatter (1m), and seismic data, and possibly bottom photos and/or qualitative descriptions of sediment samples, but no sediment samples with laboratory analysis were given the data interpretation confidence value of 2
    3Sediment texture regions that were defined on the basis of the highest resolution bathymetry (10m) and backscatter (1m), possibly bottom photos, and possibly sediment samples with laboratory analysis and/or qualitative descriptions, but no seismic interpretations were given the data interpretation confidence value of 3.
    4Sediment texture regions that were defined on the basis of the highest resolution bathymetry (10m) and/or lidar bathymetry, possibly bottom photos, and possibly sediment samples with laboratory analysis and/or qualitative descriptions, but no acoustic backscatter or seismic interpretations were given the data interpretation confidence value of 4.
    5Sediment texture regions that were defined on the basis of low-resolution leadline and/or single beam bathymetry, possibly bottom photos, and possibly sediment samples with laboratory analysis and/or qualitative descriptions were given the lowest data interpretation confidence value of 5.
    simple
    sediment nomenclature on the basis of 3 simple classes: sand, mud, hardbottom as defined in the CZM sample database (Source: U.S. Geological Survey)
    ValueDefinition
    sandSediment whose primary component (> 50%) is sand
    hardbottomSediment whose primary component is rock, boulder, cobble, or coarse gravel
    mudSediment whose primary component (> 50%) is silt and clay
    phi_class
    Sediment class as defined by Wentworth classification determined using laboratory analyzed samples in the CZM sample database. Null values are indicated as -999 and not all of these phi classes are present in this dataset. (Source: Wentworth (1922))
    ValueDefinition
    coarse gravelsediment class whose phi size is between -4 and -5
    coarse siltsediment class whose phi size is between 4 and 5
    coarse sandsediment class whose phi size is between 0 and 1
    cobblesediment class whose phi size is between -6 and -8
    fine gravelsediment class whose phi size is between -2 and -3
    fine sandsediment class whose phi size is between 2 and 3
    fine siltsediment class whose phi size is between 6 and 7
    medium gravelsediment class whose phi size is between -3 and -4
    medium sandsediment class whose phi size is between 2 and 1
    medium siltsediment class whose phi size is between 5 and 6
    very coarse gravelsediment class whose phi size is between -5 and -6
    very coarse sandsediment class whose phi size is between 0 and -1
    very fine gravelsediment class whose phi size is between -1 and -2
    very fine sandsediment class whose phi size is between 3 and 4
    very fine siltsediment class whose phi size is between 7 and 8
    -999sediment class whose phi size could not be determined from grain size data or there were no samples with laboratory analyzed grain size statistics within the polygon
    Area
    Area of feature in square kilometers using UTM, zone 19, WGS 84. (Source: Esri)
    Range of values
    Minimum:0.000001
    Maximum:90.567
    Units:square kilometers
    Resolution:0.000001
    Count_
    The number of sediment samples (with laboratory analyzed grain size statistics) that occur within each qualitatively derived polygon. This field was automatically generated by Esri when point data (sample database) is joined to a polygon (sediment texture interpretation). A value of zero indicates there are no samples within that polygon. (Source: Esri)
    Range of values
    Minimum:0
    Maximum:52
    Units:count
    Resolution:1
    Avg_Gravel
    Average percent weight (%) gravel (as determined from samples with laboratory analyzed grain size statistics) within each qualitatively derived polygon. This field was automatically generated by Esri as a summary of the numeric attributes of the points that fall inside a polygon when point data (sample database) is joined to a polygon (sediment texture interpretation). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:70.88
    Units:percent
    Avg_Sand
    Average percent weight (%) sand within each qualitatively derived polygon. This field was automatically generated by Esri as a summary of the numeric attributes of the points that fall inside a polygon when point data (sample database) is joined to a polygon (sediment texture interpretation). (Source: U.S. Geological Survey)
    Range of values
    Minimum:11.50
    Maximum:100
    Units:percent
    Avg_Silt
    Average percent weight (%) silt within each qualitatively derived polygon. This field was automatically generated by Esri as a summary of the numeric attributes of the points that fall inside a polygon when point data (sample database) is joined to a polygon (sediment texture interpretation). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:66.49
    Units:percent
    Avg_Clay
    Average percent weight (%) clay within each qualitatively derived polygon. This field was automatically generated by Esri as a summary of the numeric attributes of the points that fall inside a polygon when point data (sample database) is joined to a polygon (sediment texture interpretation). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:22.14
    Units:percent
    Avg_PHI
    Average phi size within each qualitatively derived polygon (-999 is a no data value, which means there were no samples with laboratory analyzed grain size statistics within that polygon) (Source: U.S. Geological Survey)
    Range of values
    Minimum:-2.28
    Maximum:6.63
    Units:phi
    Resolution:0.01
    MEAN
    Average seafloor elevation (NAVD 88) within each qualitatively derived polygon (-999 is a no data value, which means no mean sea-floor elevation was calculated within that polygon). (Source: U.S. Geological Survey)
    Range of values
    Minimum:-32.95
    Maximum:-1.37
    Units:meters
    Resolution:0.01

Who produced the data set?

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

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

Why was the data set created?

These sea floor sediment cover data were created from geophysical and sample data collected from Vineyard and western Nantucket Sounds, and are used to characterize the sea floor in the area. Sediment type and distribution maps are important data layers for marine resource managers charged with protecting fish habitat, delineating marine boundaries, and assessing environmental change due to natural or human impacts.

How was the data set created?

  1. From what previous works were the data drawn?
    Poppe and others, 2007 (source 1 of 12)
    Poppe, L.J., Ackerman, S.D., Foster, D.S., Blackwood, D.S., Butman, B., Moser, M.S., and Stewart, H.F., 2007, Sea-floor character and surface processes in the vicinity of Quicks Hole, Elizabeth Islands, Massachusetts: Open-File Report 2006-1357, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This publication provides the source geophysical data (backscatter and bathymetry) and bottom photographs and sediment samples for the Quicks Hole area. Two 29-foot launches deployed from the NOAA Ship Thomas Jefferson were used to acquire bathymetric and backscatter data during 2004. The multibeam bathymetric data were collected with hull-mounted 455-kHz RESON 8125 and 240-kHz RESON 8101 systems. The sidescan-sonar data were acquired with a hull-mounted Klein 5250 system operating at 100 kHz. Sediment samples and bottom photos were collected aboard the R/V Rafael with a modified Van Veen grab sampler and SEABOSS, respectively.
    Poppe and others, 2010 (source 2 of 12)
    Poppe, L.J., McMullen, K.Y., Foster, D.S., Blackwood, D.S., Williams, S.J., Ackerman, S.D., Moser, M.S., and Glomb, K.A., 2010, Geological interpretation of the sea floor offshore of Edgartown, Massachusetts: Open-File Report 2009-1001, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This publication provides the source geophysical (backscatter and bathymetry) and bottom photographs and sediment samples in the vicinity of Edgartown. Two 29-foot launches deployed from the NOAA Ship Thomas Jefferson were used to acquire bathymetric and backscatter data during 2004. The multibeam bathymetric data were collected with hull-mounted 455-kHz RESON 8125 and 240-kHz RESON 8101 systems. The sidescan-sonar data were acquired with a hull-mounted Klein 5250 system operating at 100 kHz. Sediment samples and bottom photos were collected aboard the R/V Rafael with a modified Van Veen grab sampler and SEABOSS, respectively.
    Pendleton and others, 2012 (source 3 of 12)
    Pendleton, E.A., Twichell, D.C., Foster, D.S., Worley, C.R, Irwin, B.J., and Danforth, W.W., 2012, High-resolution geophysical data from the sea floor surrounding the Western Elizabeth Islands, Massachusetts: Open-File Report 2011-1184, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided source geophysical data (sidescan, bathymetry, and seismic-reflection profiles) for portions of Vineyard Sound adjacent to the western Elizabeth Islands. Surveying was conducted aboard the RV Rafael in September 2010. Interferometric-sonar, sidescan-sonar, and chirp seismic-reflection systems were deployed simultaneously during the cruise. Bathymetric sounding data were collected with an SEA SWATHplus 234-kilohertz (kHz) interferometric sonar system. Sidescan-sonar (acoustic-backscatter) data were acquired with a Klein 3000 dual-frequency (100 and 500 kHz) sidescan-sonar system. High-resolution chirp seismic-reflection profiles were collected using an EdgeTech Geo-Star full spectrum sub-bottom (FSSB) system and SB-424 towfish.
    Andrews and others, 2014 (source 4 of 12)
    Andrews, B.D., Ackerman, S.D., Baldwin, W.E., Foster, D.S., and Schwab, W.C., 2014, High-Resolution Geophysical Data from the Inner Continental Shelf at Vineyard Sound, Massachusetts: Open-File Report 2012-1006, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided the source geophysical data (sidescan, bathymetry, and seismic-reflection profiles) for Vineyard and western Nantucket Sounds. The mapping was conducted during research cruises aboard the Megan T. Miller (2009 and 2010) and the Scarlett Isabella (2011). Bathymetric data were acquired using a Systems Engineering and Assessment, Ltd. (SEA) SWATHplus-M 234-kilohertz (kHz) interferometric sonar system, acoustic backscatter data were collected with a Klein 3000 dual-frequency sidescan-sonar (132 and 445 kHz), and chirp seismic-reflection data were collected using an EdgeTech Geo-Star FSSB subbottom profiling system and an SB-0512i towfish.
    Pendleton and others, 2014 (source 5 of 12)
    Pendleton, E.A., Andrews, B.D., Danforth, W.W., and Foster, D.S., 2014, High-resolution geophysical data collected aboard the U.S. Geological Survey research vessel Rafael to supplement existing datasets from Buzzards Bay and Vineyard Sound, Massachusetts: Open-File Report 2013-1020, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided the source geophysical data (sidescan, bathymetry, and seismic-reflection profiles) for central portions of Vineyard and western Nantucket Sounds. These areas were surveyed with the RV Rafael in 2010 and 2011. In 2010, seismic-reflection data were acquired with a boomer source and GeoEel 8-channel streamer. Interferometric-sonar, sidescan-sonar, and Knudsen seismic-reflection systems were deployed simultaneously during cruise 2011. Bathymetry data were collected with an SEA SWATHplus 234-kilohertz (kHz) interferometric sonar, Sidescan-sonar (acoustic-backscatter) data were acquired with a Klein 3000 dual-frequency (100 and 500 kHz) sidescan sonar, and high-resolution chirp seismic data were collected using a dual frequency (3.5 and 200 kHz) Knudsen Engineering Limited (KEL) Chirp 3202 system.
    CZM sample database (source 6 of 12)
    Ford, K.H., Huntley, E.C., Sampson, D.W., and Voss, S., Unpublished Material, Massachusetts Sediment Database.

    Other_Citation_Details:
    This sample database has been compiled and vetted from existing samples and datasets by the Massachusetts Office of Coastal Zone Management. The data are currently unpublished, but may be acquired by contacting the CZM office: 251 Causeway St Boston, MA 02114 (617) 626-1000 czm@state.ma.us
    Type_of_Source_Media: digital vector
    Source_Contribution:
    Sediment sample databases of Ford and Voss (2010) and McMullen and others (2011) were combined then edited and supplemented with NOAA chart sampling data and bottom photos and descriptions by a group of GIS specialists at the Massachusetts Office of Coastal Zone Management (Emily Huntley, personal communication). These data contained sediment laboratory statistics when available, visual descriptions if sediment analysis was not performed or if the site was a bottom photograph, and classification fields of Barnhardt and others (1998), Shepard (1954), and Wentworth (1922) as well as average sediment statistics and phi size, when laboratory analysis was conducted.
    Poppe and others, 2008 (source 7 of 12)
    Poppe, L.J., McMullen, K.Y., Foster, D.S., Blackwood, D.S., Williams, S.J., Ackerman, S.D., Barnum, S.R., and Brennan, R.T., 2008, Sea-floor character and sedimentary processes in the vicinity of Woods Hole, Massachusetts: Open File Report 2008-1004, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This publication provides the source geophysical data (backscatter and bathymetry) and bottom photographs and sediment samples for Woods Hole. Two 29-foot launches deployed from the NOAA Ship Whiting were used to acquire bathymetric and backscatter data during 2001. The bathymetric data were collected with a hull-mounted 240-kHz RESON 8101 shallow-water system aboard launch 1005. The sidescan-sonar data were acquired with a hull-mounted Klein T-5000 system operating at 455 kHz aboard launch 1014. Sediment samples and bottom photos were collected aboard the R/V Rafael with a modified Van Veen grab sampler and SEABOSS, respectively, in 2007.
    Ackerman and others, 2014 (source 8 of 12)
    Ackerman, S.D., Pappal, A.L., Huntley, E.C., Blackwood, D.S., and Schwab, W.C., 2015, Geological Sampling Data and Benthic Biota Classification: Buzzards Bay and Vineyard Sound, Massachusetts: Open file Report 2014-1221, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided high-resolution digital photographs of the Vineyard Sound and Buzzards Bay Seafloor. At each station, the USGS SEABOSS was towed approximately one meter off the bottom at speeds of less than one knot. Because the recorded position is actually the position of the GPS antenna on the survey vessel, not the SEABOSS sampler, the estimated horizontal accuracy of the sample location is ± 30 meters (m). Photographs were obtained using a Konica-Minolta DiMAGE A2 digital still camera, and continuous video was collected from a Kongsberg Simrad OE1365 high-resolution color video camera, usually for 5 to 15 minutes. These data were important in defining rocky zones where sediment samples do not exist.
    USACE-JALBTCX, 2009 (source 9 of 12)
    U.S. Army Corps of Engineers - Joint Airborne Lidar Bathymetry Center of Expertise, 2009, 2005 - 2007 US Army Corps of Engineers (USACE) Topo/Bathy Lidar: Maine, Massachusetts, and Rhode Island: NOAA National Ocean Service (NOS), Coastal Services Center (CSC), Charleston, SC.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    The source lidar data for the very nearshore (< -5 m) region along the northern shoreline of Vineyard and western Nantucket Sounds. Lidar (Light Detection and Ranging) data were acquired with a SHOALS-1000T (for hydrographic & topographic data) using the Joint Airborne Joint Airborne LiDAR Bathymetry Center of Expertise (JALBTCX) lidar plane. These data are now publically available in LAS lidar format via NOAA's Digital Coast website.
    NOAA, 2008 (source 10 of 12)
    National Oceanic and Atmospheric Administration, 2008, Descriptive report, navigable area survey H11920, Vineyard Sound, Massachusetts, Gay Head to Cedar Tree Neck: National Oceanographic and Atmospheric Administration - National Ocean Survey, Norfolk, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    The Bathymetry Attributed Grid (BAG) files accompanying this publication provide the source bathymetry data for portions of Vineyard Sound around the Menemsha Bight. Two 29-foot launches deployed from the NOAA Ship Thomas Jefferson were used to acquire bathymetry during 2008 using hull-mounted 455-kHz RESON 8125 and 240-kHz RESON 8101 systems.
    NOAA, 2008 (source 11 of 12)
    National Oceanic and Atmospheric Administration, 2008, Descriptive report, navigable area survey H11921, Vineyard Sound, Massachusetts, Sow and Pigs reef to Quicks Hole: National Oceanographic and Atmospheric Administration - National Ocean Survey, Norfolk, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    The BAG and TIFF files accompanying this publication provide the source geophysical data (backscatter and bathymetry) for portions of Vineyard Sound around Cuttyhunk Island and Quicks Hole. Two 29-foot launches deployed from the NOAA Ship Thomas Jefferson were used to acquire bathymetric and backscatter data during 2008. The multibeam bathymetric data were collected with hull-mounted 455-kHz RESON 8125 and 240-kHz RESON 8101 systems. The sidescan-sonar data were acquired with a hull-mounted Klein 5250 system operating at 100 kHz.
    NOAA Single-Beam Soundings (source 12 of 12)
    NOAA National Geophysical Data Center, 2015, NOS Hydrographic Survey Data.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    These data include NOAA lead-line and single-beam sonar soundings, which were used to cover areas where no swath bathymetry or lidar data exist.
  2. How were the data generated, processed, and modified?
    Date: 2014 (process 1 of 7)
    The texture and spatial distribution of sea-floor sediment were qualitatively analyzed in ArcGIS using several input data sources (listed in the source contribution), including acoustic backscatter, bathymetry, seismic-reflection profile interpretations, bottom photographs, and sediment samples. The interpretation was initiated by digitizing a polygon shapefile (file > new > shapefile in ArcCatalog 9.3.1, then editor > 'create new feature' in ArcMap 9.3.1) around the extent of the regional bathymetric DEM (see vns10m_navd88 in the larger work citation). The polygon was then partitioned into multiple sediment texture polygons using 'cut polygon' and 'auto-complete polygon' in an edit session. In general, polygon editing was done at scales between 1:5,000 and 1:20,000, depending on the size of the traced feature and the resolution of the source data. Some areas interpreted as a single sediment textural unit may contain multiple polygons that indicate different interpretation confidence levels. The following numbered steps outline the workflow of the data interpretation. 1. Backscatter intensity data (available at 1 m resolution) was the first input. Changes in backscatter amplitude were digitized to outline possible changes in sea-floor texture on the basis of acoustic return. Areas of high backscatter (light colors) have strong acoustic reflections and suggest boulders, gravels, and generally coarse sea-floor sediments. Low-backscatter areas (dark colors) have weak acoustic reflections and are generally characterized by finer grained material such as muds and fine sands. 2. The polygons were then refined and edited using gradient, rugosity, and hillshaded relief images derived from interferometric and multibeam swath bathymetry and (available at 10 m resolutions). Areas of rough topography and high rugosity are typically associated with rocky areas, while smooth, lower-relief regions tend to be blanketed by fine-grained sediment. These bathymetric derivatives helped to refine polygon boundaries where changes from primarily rock to primarily gravel may not have been apparent in backscatter data, but could easily be identified in hillshaded relief and slope changes. 3. The third data input (where available) was the stratigraphic interpretation of seismic-reflection profiles, which further constrained the extent and general shape of sea-floor sediment distributions and rocky outcrops, and also provided insight concerning the likely sediment texture of the feature on the basis of pre-Quaternary, glacial or post-glacial origin. Seismic lines and the surficial geologic maps derived from them and used here as input data were collected at typically 100-meter spacing, with tie-lines generally spaced 1-km apart. 4. After all the sea-floor features were traced from the geophysical data, a new field was created in the shapefile called 'sed_type'. Seafloor composition observations from sediment samples and bottom photographs/video were used to define sediment texture for the polygons using Barnhardt and others (1998) classification. Samples with laboratory grain size analysis were preferred over visual descriptions when defining sediment texture throughout the study area. Bottom photo stations are typically around 2-km apart, and the density of sediment samples varies throughout the study area. Some polygons contained more than one sample with grain-size statistics, while others contained none. For multiple samples within a polygon, the dominant sediment texture (or average phi size) was used to classify sediment type (often aided by the 'data join' sediment statistics described in a later processing step). In rocky areas, bottom photos were used in the absence of sediment samples to qualitatively define sediment texture. Polygons that lacked sample information were texturally defined through extrapolation from adjacent or proximal polygons of similar acoustic character that did contain sediment samples. 219 samples within the study area were analyzed in the laboratory for grain size. Bottom photo stations are typically around 2-km apart, and the density of sediment samples varies throughout the study area. Person who carried out this activity:
    Wayne Baldwin
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Data sources used in this process:
    • All source geophysical data and seafloor sediment observation data
    Date: 2014 (process 2 of 7)
    After some additional qualitative polygon editing and reshaping was done in order to create a sediment map that was in the best agreement with all input data: lidar, bathymetry, backscatter, seismic interpretations, bottom photographs, and sediment samples, 3 more fields were added (ArcMap version 9.3.1). The first field, 'simple' is just 3 classes: sand, mud, or hardbottom. Another field 'phi_class' was created and defined using the Wentworth (1922) sediment classification, and finally, a field 'ConfLevel' was added as a data interpretation confidence, which describes how confident we are in the interpretation on the basis of the number and quality of the input data sources (see the entity and attribute sections for more information on these fields). The remaining fields contain sediment texture statistics or mean water depth information and were created and populated using data joins or zonal statistics functions within ArcMap (version 9.3.1). The fields beginning with "Avg_" and the 'Count_' field were automatically generated by computing a data join where the CZM sample database (vector points) was edited to include only the samples with laboratory sediment analysis and joined to the qualitatively derived polygon file. Each polygon was given an average of the numeric attributes of the points (with laboratory grain size analysis) that fall inside it, and the count field shows how many laboratory analyzed points fall inside it. 219 samples were analyzed in the laboratory. Several fields that were not wanted were deleted after the join. A mean water depth (NAVD 88) field was created using ArcMap (version 9.3): ArcToolbox - Spatial Analyst Tools > Zonal > Zonal Statistics as Table, where the mean water depth for each polygon (input zone data using the zone field sed_type) was derived from the regional bathymetric DEM (see vns10m_navd88 in the larger work citation). No data raster values were ignored in determining the output value for each polygon zone. If all raster values were null within a polygon, that zone had a null value (changed to -999) for that zone. The output was saved to a table, which was joined with the sediment type polygon shapefile. All of the joined fields except MEAN were turned off, and the joined shapefile was exported to a new shapefile. Person who carried out this activity:
    Wayne Baldwin
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Data sources used in this process:
    • polygon shapefile containing sediment texture units and point shapefile containing seafloor sediment observations
    Date: 2014 (process 3 of 7)
    The polygon shapefile containing sediment texture units with joined sediment sample lab statistics was imported as a feature class within a file geodatabase feature dataset, and topological rules were established (ArcCatalog 9.3.1). Topological errors, primarily overlaps and gaps, were identified and remedied using the topology toolbar in ArcMap (9.3.1). Person who carried out this activity:
    Wayne Baldwin
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Data sources used in this process:
    • polygon shapefile containing sediment texture units with joined sediment sample lab statistics
    Date: 2014 (process 4 of 7)
    The sediment texture polygon feature class was exported back to a shapefile and the 'Shape_Area' and 'Shape_Length' fields were deleted from its attribute table (ArcCatalog and ArcMap 9.3.1). XTools Pro (7.1.0) was then used to add and populate a new attribute field containing polygon area in square kilometers based on UTM, zone 19 N, WGS84. Finally, the shapefile was reprojected from UTM zone 19 N, WGS84 to GCS WGS84 using ArcToolbox > Data Management Tools > Projections and Transformations > Feature > Project. Person who carried out this activity:
    Wayne Baldwin
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Data sources used in this process:
    • sediment texture polygon feature class
    Date: 20-Jul-2018 (process 5 of 7)
    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: 18-Nov-2019 (process 6 of 7)
    Crossref DOI link was added as the first link in the metadata. 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 7 of 7)
    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?
    Kelley, J.T., Barnhardt, W.A., Belknap, D.F., Dickson, S.M., and Kelley, A.R., 1998, The Seafloor Revealed: The Geology of the Northwestern Gulf of Maine Inner Continental Shelf: Maine Geological Survey Open-File Report 96-6, Maine Geological Survey, Natural Resources Information and Mapping Center, Augusta, Maine.

    Online Links:

    Barnhardt, W.A., Kelley, J.T., Dickson, S.M., and Belknap, D.F., 1998, Mapping the Gulf of Maine with Side-scan Sonar: a New Bottom-type Classification for Complex Seafloors: Journal of Coastal Research 14(2), Coastal Education and Research Foundation, Inc., Royal Palm Beach, FL.

    McMullen, K.Y., Paskevich, V.F., and Poppe, L.J., 2011, GIS data catalog (version 2.2), in Poppe, L.J., Williams, S.J., and Paskevich, V.F., eds., 2005, USGS East-coast Sediment Analysis: Procedures, Database, and GIS Data: Open-File Report 2005-1001, U.S. Geological Survey, Reston, VA.

    Online Links:

    Ford, K.H., and Voss, S.E, 2010, Seafloor Sediment Composition in Massachusetts Determined Using Point Data: Massachusetts Division of Marine Fisheries Technical Report TR-45, Massachusetts Division of Marine Fisheries, New Bedford, MA.

    Online Links:


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?
    These data were produced qualitatively from acoustic and sample data with varying resolutions. Horizontal uncertainty associated with sample collection especially, can be quite high (100's of meters), much higher than positional uncertainty associated with acoustic data (usually less than <10's of meters). The date of sample collection and ship station positioning all contribute to sample position uncertainty. These qualitatively derived polygons outlining sea floor features are estimated to be within 50 meters, horizontally, but locally may be higher when sediment texture delineation is based on sample information alone.
  3. How accurate are the heights or depths?
    Although there is a field for mean water depth, there is no assumption of vertical accuracy. The depth value is an average of all grid cells of the regional bathymetric DEM (see vns10m_navd88 in the larger work citation) within each polygon. In many cases the mean depth value covers a range of depths from near zero to < -20 meters, and as such should not be used for navigation or taken as an absolute depth value within a polygon.
  4. Where are the gaps in the data? What is missing?
    These sediment cover data are defined for areas where source data exists. In general, gaps in the coverage coincide with gaps in the source data. However, some small data gaps were interpreted through extrapolation. Areas of lower data quality and incomplete coverage are noted in a data confidence attribute field.
  5. How consistent are the relationships among the observations, including topology?
    These data were drawn and vetted for accuracy using the source input rasters and point sample data described in the processing steps and source contributions. Overlapping features and unintentional gaps within the survey area were identified using the topology checker in ArcMap (version 9.3.1) and corrected or removed. Not all digitized sea floor features contained sample information, so often the sea floor texture is characterized by the nearest similar feature that contains a sample. Conversely, sometimes a digitized feature contained multiple samples and not all of the samples within the feature were in agreement (of the same texture). In these cases all data were considered, and the dominant sediment texture from sample analyses did not necessarily determine the primary texture assigned to a polygon. Samples from rocky areas often only consist of bottom photographs, because large particle size often prevents the recovery of a sediment sample. Bottom photo classification can be subjective, such that determining the sediment type that is greater than 50% of the view frame is estimated by the interpreter and may differ among interpreters. Bottom photo transects often reveal changes in the sea floor over distances of less than 100 m and these changes are often not observable in acoustic data. Heterogeneous sea floor texture can change very quickly, and many small-scale changes will not be detectable or mappable at a scale of 1:25,000. The boundaries of polygons are often inferred on the basis of sediment samples, and even boundaries that are traced on the basis of amplitude changes in geophysical data are subject to migration. Polygon boundaries should be considered an approximation of the location of a change in texture.

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. Additionally, there are limitations associated with qualitative sediment mapping interpretations. Because of the scale of the source geophysical data and the spacing of samples, not all changes in sea floor texture are captured. The data were mapped between 1:5,000 and 1:20,000, but the recommended scale for application of these data is 1:25,000.
  1. Who distributes the data set? (Distributor 1 of 1)
    Wayne Baldwin
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
  2. What's the catalog number I need to order this data set? VineyardNantucketSound_sedcover.zip from USGS Open File report 2016-1119. WinZip v. 14.5 file contains qualitatively derived polygons that define sea floor texture and distribution from Vineyard and western Nantucket Sounds, MA and the associated metadata.
  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 U.S. Geological Survey 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?
    These data are available in Environmental Systems Research Institute (Esri) shapefile format. The user must have software capable of importing and processing this data type.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
U.S. Geological Survey
Attn: Wayne Baldwin
Geologist
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 x2226 (voice)
508-457-2310 (FAX)
wbaldwin@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

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