Nahant_NH_Pzones: Physiographic Zones of the Sea Floor from Nahant to Salisbury, Massachusetts (polygon shapefile, Geographic WGS 84)

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Frequently anticipated questions:

What does this data set describe?

Title:
Nahant_NH_Pzones: Physiographic Zones of the Sea Floor from Nahant to Salisbury, Massachusetts (polygon shapefile, Geographic WGS 84)
Abstract:
These data are qualitatively derived interpretive polygon shapefiles defining sediment type and distribution, and physiographic zones of the sea floor from Nahant to Salisbury, Massachusetts. Many of the geophysical data used to create the interpretive layers were collected under a cooperative agreement among the Massachusetts Office of Coastal Zone Management (CZM), the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Army Corps of Engineers (USACE). Initiated in 2003, the primary objective of this program is to develop regional geologic framework information for the management of coastal and marine resources. Accurate data and maps of seafloor-geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes because of natural or human effects. The project is focused on the inshore waters of coastal Massachusetts. Data collected during the mapping cooperative involving the USGS have been released in a series of USGS Open-File Reports (<http://woodshole.er.usgs.gov/project-pages/coastal_mass/geophydata.html>). The interpretations released in this study are for an area extending from the southern tip of Nahant north to Salisbury, Massachusetts. A combination of geophysical and sample data including high-resolution bathymetry and lidar, acoustic-backscatter intensity, seismic-reflection profiles, bottom photographs, and sediment samples was used to create the data interpretations. Most of the nearshore geophysical and sample data (including the bottom photographs) were collected during several cruises between 2000 and 2008. More information about the cruises and the data collected can be found at the Geologic Mapping of the Massachusetts Sea Floor Web page: <http://woodshole.er.usgs.gov/project-pages/coastal_mass/>.
  1. How should this data set be cited?

    Pendleton, Elizabeth, 2015, Nahant_NH_Pzones: Physiographic Zones of the Sea Floor from Nahant to Salisbury, Massachusetts (polygon shapefile, Geographic WGS 84): Open-File Report 2015-1153, 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., Barnhardt., W.A., Baldwin, W.E., Foster, D.S., Schwab, W.C., Andrews, B.D., and Ackerman, S.D., 2015, Sea-Floor Texture and Physiographic Zones of the Inner Continental Shelf From Salisbury to Nahant, Massachusetts, Including the Merrimack Embayment and Western Massachusetts Bay: Open-File Report 2015-1153, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.876421
    East_Bounding_Coordinate: -70.498785
    North_Bounding_Coordinate: 42.737110
    South_Bounding_Coordinate: 42.276833

  3. What does it look like?

    <https://pubs.usgs.gov/of/2015/1153/GIS_catalog/PhysiographicZones/pzones_browse.png> (PNG)
    Image of the physiographic zone shapefile for the Massachusetts inner continental shelf from Nahant to Salisbury

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 01-Jan-1994
    Ending_Date: 07-May-2008
    Currentness_Reference: ground condition of data used to derive the interpretation

  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 (210)

    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?

    Nahant_NH_Pzones
    Physiographic zones shapefile for Nahant to Salisbury, Massachusetts (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.

    Physio
    Based on geologic maps produced for the Western Gulf of Maine (Kelley and others, 1989), the seafloor within the study area can be divided into geologic environments, or physiographic zones, which are delineated based on Seafloor morphology and the dominant texture of surficial material. (Source: U.S. Geological Survey)

    ValueDefinition
    Rocky ZoneRocky Zones (RZ) are rugged areas of extreme bathymetric relief ranging from nearly vertical rock cliffs to relatively flat, gravel-covered plains littered with boulders up to 4 m in diameter.
    Nearshore BasinNearshore Basins (NB) are areas of shallow, low-relief seafloor adjacent to the mainland and separated from offshore areas by islands and shoals.
    Nearshore RampNearshore Ramps (NR) are areas of gently-sloping seafloor with generally shore-parallel bathymetric contours. This zone is primarily covered with sand-rich sediment, although small exposures of ledge, cobbles and boulders locally crop out on the seafloor.
    Shelf ValleyShelf Valleys (SV) are elongate depressions that extend offshore more or less perpendicular to the trend of the coastline, and slope gently seaward.
    Outer BasinOuter Basins are generally found in water depths greater than 40 meters, and are finer grained, but may contain occasional rock outcrops.
    Hard-bottom PlainsHard-bottom Plains tend to have low bathymetric relief, with a coarse sediment texture consisting of primarily gravel, sand, and rock.

    Shape_Leng
    Length in meters (UTM, zone 19, WGS84) of each defined polygon automatically calculated when part of a geodatabase. (Source: U.S. Geological Survey)

    Range of values
    Minimum:359.72
    Maximum:258190.70928
    Units:meters
    Resolution:50

    Shape_Area
    Area of feature in meters squared. (Source: U.S. Geological Survey)

    Positive real numbers that are automatically generated.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA 02543-1598
    USA

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

Why was the data set created?

These sea-floor physiographic zones were created from geophysical and sample data collected from Nahant to Salisbury, and are used to characterize the seafloor in the area. Physiographic zone 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?

    Barnhardt and others, 2006 (source 1 of 12)
    Barnhardt, W.A., Andrews, B.D., and Butman, Bradford, 2006, High-Resolution Geologic Mapping of the Inner Continental Shelf: Nahant to Gloucester, Massachusetts: Open-File Report 2005-1293, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided the published physiographic zone interpretations for an area from Nahant to Gloucester, Massachusetts. The physiographic zone interpretations in this study are adjacent to the physiographic zones in Barnhardt and others (2006) and Barnhardt and others (2009). The interpretations should be nearly seamless and continuous among the 3 interpretations.

    Barnhardt and others, 2009 (source 2 of 12)
    Barnhardt, W.A., Andrews, B.D., Ackerman, S.D., Baldwin, W.E., and Hein, C.J., 2009, High-Resolution Geologic Mapping of the Inner Continental Shelf: Cape Ann to Salisbury Beach, Massachusetts: Open-File Report 2007-1373, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided the published physiographic zone interpretations for an area from Cape Ann to Salisbury, Massachusetts. The physiographic zone interpretations in this study are adjacent to the physiographic zones in Barnhardt and others (2006) and Barnhardt and others (2009). The interpretations should be nearly seamless and continuous among the 3 interpretations.

    Butman and others, 2007 (source 3 of 12)
    Butman, B., Valentine, P.C., Middleton, T.J., and Danforth, W.W., 2007, A GIS Library of Multibeam Data for Massachusetts Bay and the Stellwagen Bank National Marine Sanctuary, Offshore of Boston, Massachusetts: Digital Data Series 99, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided the source geophysical data (sidescan and bathymetry) for the western Massachusetts Bay region including Stellwagen Bank. These data were acquired between 1994 and 1998 by the USGS, Canadian Hydrographic Survey, and University of New Brunswick aboard the Frederick G. Creed. Bathymetric and backscatter data were acquired using Simrad Subsea EM 1000 Multibeam Echo Sounder. These data formed the basis of the physiographic zone interpretations and are included as a source layer in Pendleton and others (2013).

    CZM sample database (source 4 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) 626-1200 czm@state.ma.us
    This is part of the following larger work.

    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:

    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 over 2,000 bottom photos and descriptions at more than 400 stations 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.

    USACE- JALBTCX, 2008 (source 5 of 12)
    U.S. Army Corps of Engineers, Joint Airborne LiDAR Bathymetry Center of Expertise, 2008, Massachusetts LiDAR Grid Data in Coastal Areas: Lidar Data MA coastline, Fugro Pelagos, Inc, San Diego, CA.

    Type_of_Source_Media: disc
    Source_Contribution:
    This report provided the source lidar data for the very nearshore (< -5 m) region. Lidar (Light Detection and Ranging) data were acquired with a SHOALS-1000T (for hydrographic & topographic data) using the Joint Airborne LiDAR Bathymetry Center of Expertise (JALBTCX) lidar plane.

    Gutierrez and others, 2000 (source 6 of 12)
    Gutierrez, B.J., Butman, Bradford, and Blackwood, D.S., 2000, Photographs of the Sea Floor in Western Massachusetts Bay, Offshore of Boston, Massachusetts, July, 1999: Open-File Report 00-427, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided the photographs of the seafloor in western Massachusetts Bay. These data were acquired in 1999 by the USGS aboard the Fishing Vessel Isabel S using SEABOSS (Blackwood and Parolski, 2000). The photographs and samples were used to validate physiographic zones interpretations and sediment texture

    USGS Color Ortho Imagery (2008/2009) (source 7 of 12)
    U.S. Geological Survey, 2009, MassGIS Data - USGS Color Ortho Imagery (2008/2009): MassGIS Data April 2008/2009, MassGIS, Boston, MA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    These data provided the aerial photograph data for the very nearshore and shoreline region and were used to guide the physiographic zone interpretation in the absence of geophysical data. Photographs from the north shore were acquired in 2008 by Fugro Earthdata, Inc under contract of the U.S. Geological Survey at 30-cm resolution. The data are distributed by the Massachusetts Office of Geographic Information (MassGIS).

    Pendleton and others (2013) (source 8 of 12)
    Pendleton, E.A., Baldwin, W.E., Barnhardt, W.A., Ackerman, S.D., Foster, D.S., Andrews, B.D., and Schwab, W.C., 2013, Shallow Geology, Seafloor Texture, and Physiographic Zones of the Inner Continental Shelf from Nahant to Northern Cape Cod Bay, Massachusetts: Open-File Report 2012-1157, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report merged and published several topographic, bathymetric and backscatter datasets collected between 1998 and 2009. These data were used as source layers for creating and expanding the physiographic zone interpretations.

    Oldale and Bick, 1987 (source 9 of 12)
    Oldale, R.N., and Bick, Jennifer, 1987, Maps and seismic profiles showing geology of the inner continental shelf, Massachusetts Bay, Massachusetts: Miscellaneous Field Studies Map 1923, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: paper
    Source_Contribution:
    This report provided a surficial geologic interpretation of Massachusetts Bay. The maps made by Oldale and Bick (1987) provided information regarding the likely geologic origin of the sediments of the seafloor, and although the maps were low-resolution compared to the study presented here, they informed the sediment texture interpretations and physiographic zone determination especially in areas of limited sample coverage.

    Oldale and Wommack, 1987 (source 10 of 12)
    Oldale, R.N., and Wommack, L.E., 1987, Maps and seismic profiles showing geology of the inner continental shelf, Cape Ann, Massachusetts to New Hampshire: Miscellaneous Field Studies Map 1892, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: paper
    Source_Contribution:
    This report provided a surficial geologic interpretation of the southern Merrimack Embayment. The maps made by Oldale and Wommack (1987) provided information regarding the likely geologic origin of the sediments of the seafloor, and although the maps were low-resolution compared to the study presented here, they informed the sediment texture interpretations and physiographic zone determination especially in areas of limited sample coverage.

    Hein and others, 2013 (source 11 of 12)
    Hein, C.J., FitzGerald, D.M., Barnhardt, W.A., and Stone, B.D., 2013, Onshore-Offshore Surficial Geologic Map of the Newburyport East and Northern Half of the Ipswich Quadrangles, Massachusetts: Geologic Map GM-13-01, Massachusetts Geological Survey, Amherst, MA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This report provided geospatial vector data of surficial geologic interpretations from Cape Ann to New Hampshire. These interpretations of shallow and surficial geology were based on the data of Barnhardt and others (2009). The geospatial information was used to guide sediment texture interpretations and physiographic zone determinations.

    Oldale and others, 1994 (source 12 of 12)
    Oldale, R.N., Knebel, H.J., and Bothner, M.H., 1994, Submerged and Eroded Drumlins off Northeastern Massachusetts: Geomorphology 9, Elsevier, Philadelphia, PA.

    Type_of_Source_Media: paper
    Source_Contribution:
    This paper provided a map of submerged drumlins offshore of Boston Harbor. These identified areas of till and lag deposits were used to aid the interpretation of surficial sediment cover and physiographic zones.

  2. How were the data generated, processed, and modified?

    Date: 15-Mar-2014 (process 1 of 3)
    The spatial distribution of sea-floor features were qualitatively-analyzed in ArcGIS using several input data sources, including acoustic backscatter, bathymetry, Lidar, bottom photographs, and sediment samples. In order to create the interpretation, first a polygon feature class was created inside a geodatabase by importing a polygon shapefile of the survey area (with ArcMap version 10.2). The feature class was then edited using 'cut polygon' in an edit session. The polygon cuts were done qualitatively based on slope changes in the bathymetry, backscatter intensity changes in the sidescan sonar mosaics, surficial geologic interpretations, bottom photographs and sediment samples. The polygon editing was done at a general zoom scale of 1:12,000.

    Person who carried out this activity:

    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA 02543-1598
    USA

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

    Date: 05-Apr-2014 (process 2 of 3)
    After all the traced features were mapped, a new field was created 'Physio', and the sea floor was characterized for each polygon based on physiographic zones descriptions of Kelley and others (1996).

    Person who carried out this activity:

    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA 02543-1598
    USA

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

    Date: 02-Jun-2014 (process 3 of 3)
    Finally, new topology rules were established for the feature dataset within the geodatabase. This was done to make sure that there were no overlapping polygons or unintentional gaps between adjacent polygons. The topology error inspector (ArcMap version 10.2) was used to find topology errors and fix them. All overlapping polygon errors were fixed, and several gaps were marked as exceptions since there are several islands and some data gaps within the study area. The data were then exported to a shapefile and the polygons were reprojected from UTM Zone 19N, WGS84 to GCS WGS84.

    Person who carried out this activity:

    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    U.S.Geological Survey
    Woods Hole, MA 02540
    USA

    (508)-548-8700 x2259 (voice)
    (508)-457-2310 (FAX)
    ependleton@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., 1996, 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, ME.

    McMullen, K.Y, Paskevich, V.F., and Poppe, L.J., 2012, 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:

    Blackwood, D.S., and Parolski, K.F., 2000, "Seaboss": an elegantly simple image and sample collecting system: Proceedings, 6th Annual International Conference on Remote Sensing for Marine Environments Volume 1, Veridian ERIM International, Charleston, SC.

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?

  4. Where are the gaps in the data? What is missing?

    These physiographic zones are defined for areas where source data exist. In general, gaps in the coverage coincide with gaps in the source data. However, some small data gaps were interpreted through extrapolation.

  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 10.2) and corrected or removed.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_Constraints:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Additionally, there are limitations associated with qualitative seafloor 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 1:8,000 and 1:25,000, but the recommended scale for application of these data is 1:25,000. Features below 5,000 m2 or less than 50 m wide were not digitized due to positional uncertainty, lack of sample information, and the often ephemeral nature of small-scale sea floor features. Not all digitized sea floor features contained sample information, so often the physiographic zone 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. In these cases the dominant sample texture was chosen to represent the primary sediment type for the 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 based on sediment samples, and even boundaries that are traced based on amplitude changes in geophysical data are subject to migration. Polygon boundaries should be considered an approximation of the location of a change in physiographic zone.

  1. Who distributes the data set? (Distributor 1 of 1)

    Elizabeth A Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA 02543-1598
    USA

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

  2. What's the catalog number I need to order this data set?

    USGS open file report 2015-1153 Physiographic Zones from Nahant to NH. The zip file contains a shapefile (Nahant_NH_pzones), a browse graphic (pzones_browse.png) and FGDC CSDGM metadata files in four standard formats.

  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 the data file.

Who wrote the metadata?

Dates:
Last modified: 02-Jul-2014
Metadata author:
Elizabeth A. Pendleton
U.S. Geological Survey
Geologist
U.S. Geological Survey
Woods Hole, MA 02543-1598
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)

Generated by mp version 2.9.21 on Tue Aug 18 10:13:16 2015