Pendleton, Elizabeth, 2013, NAH_CCB_Pzones: Physiographic Zones of the Sea Floor from Nahant to Northern Cape Cod Bay, Massachusetts (polygon shapefile, Geographic WGS 84): Open-File Report 2012-1157, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.This is part of the following larger work.Online Links:
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, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
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.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
| Value | Definition |
|---|---|
| Rocky Zone | Rocky 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 Basin | Nearshore Basins (NB) are areas of shallow, low-relief seafloor adjacent to the mainland and separated from offshore areas by islands and shoals. |
| Nearshore Ramp | Nearshore 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 Valley | Shelf Valleys (SV) are elongate depressions that extend offshore more or less perpendicular to the trend of the coastline, and slope gently seaward. |
| Ebb Tidal Delta | Ebb-tidal Deltas are lobate sandy shoals found on the seaward side of tidal inlets that form through the interaction of waves and ebbing tidal currents |
| Outer Basin | Outer Basins are generally found in water depths greater than 40 meters, and are finer grained, but may contain occasional rock outcrops. |
| Hard-Bottom Plains | Hard-bottom Plains tend to have low bathymetric relief, with a coarse sediment texture consisting of primarily gravel, sand, and rock. |
| Sand Waves | Sand Waves are features developed by currents over the sea floor. |
| Dredged Channel | Dredged Channels are anthropogenic features where the sea floor has been modified to accommodate navigation. |
| Range of values | |
|---|---|
| Minimum: | 0.900 |
| Maximum: | 345.532 |
| Units: | square-kilometers |
| Resolution: | 0.001 |
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
These sea floor physiographic zones were created from geophysical and sample data collected from Nahant to Northern Cape Cod Bay, and are used to characterize the sea floor 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.
Ackerman, S.D., Butman, B., Barnhardt, W.A., Danforth, W.W., and Crocker, J.M., 2006, High-resolution Geologic Mapping of the Inner Continental Shelf: Boston Harbor and Approaches, Massachusetts: Open-File Report 2006-1008, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.Online Links:
Andrews, B.D., Ackerman, S.D., Baldwin, W.E., and Barnhardt, W.A., 2010, Geophysical and Sampling Data from the Inner Continental Shelf: Northern Cape Cod Bay, Massachusetts: Open-File Report 2010-1006, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.Online Links:
Barnhardt, W.A., Ackerman, S.D., Andrews, B.D., and Baldwin, W.E., 2010, Geophysical and Sampling Data from the Inner Continental Shelf: Duxbury to Hull, Massachusetts: Open-File Report 2009-1072, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.Online Links:
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, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.Online Links:
Ford, K.H., Huntley, E.C., Sampson, D.W., and Voss, S., Unpublished Material, Massachusetts Sediment Database:,.
U.S. Army Corps of Engineers, Joint Airborne LiDAR Bathymetry Center of Expertise, 2008, Massachusetts LiDAR Grid Data in Coastal Areas: Fugro Pelagos, Inc, San Diego, CA.
Poppe, L.J., Paskevich, V.F., Butman, B., Ackerman, S.D., Danforth, W.W., Foster, D.S., and Blackwood, D.S., 2006, Geological Interpretation of Bathymetric and Backscatter Imagery: Open-File Report 2005-1048, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.Online Links:
Person who carried out this activity:
508-548-8700 x2355 (voice)
508-457-2310 (FAX)
wbarnhardt@usgs.gov
Person who carried out this activity:
508-548-8700 x2355 (voice)
508-457-2310 (FAX)
wbarnhardt@usgs.gov
Person who carried out this activity:
(508)-548-8700 x2259 (voice)
(508)-457-2310 (FAX)
ependleton@usgs.gov
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, Maine.
McMullen, K.Y, Paskevich, V.F., and Poppe, L.J., 2011, USGS East-coast Sediment Analysis: Procedures, Database, and GIS Data: Open File Report 2005-1001, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.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:
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.
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.
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. Qualitatively-defined polygons for the Boston Harbor and approaches region had already been drawn and published by Ackerman and others (2006). In their study, their region of interest was defined by using a 'convert raster to feature' function on sidescan sonar imagery within ArcGIS. This conversion task created several very small (~ 1 square-meter) triangular and rectilinear-shaped gaps along the boundaries of the defined polygons within Boston Harbor. The original Ackerman and other (2006) bottom type polygons were merged with the polygons created in this study, and polygon and field editing was done in order to make them fit the physiographic zones used in this report. However, the very small topology errors associated with the original data have not been removed, primarily because they are well below the intended scale of application of these data (1:25,000). Overlapping features and unintentional gaps within the rest of the survey area were identified using the topology checker in ArcMap (version 9.3.1) and corrected or removed.
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.
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
Downloadable Data
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.
| Data format: | WinZip file contains qualitatively derived polygons that define physiographic zones from Nahant to Northern Cape Cod Bay, MA and the associated metadata in format WinZip (version 14.5) Esri Polygon Shapefile Size: 0.8 MB |
|---|---|
| Network links: |
<http://pubs.usgs.gov/of/2012/1157/GIS_catalog/PhysiographicZones/PhysioZones.zip> <http://pubs.usgs.gov/of/2012/1157/html/GIS_catalog.html/> <http://pubs.usgs.gov/of/2012/1157/> |
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.
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
