| This section describes the qualitatively-derived data interpretation and selected source data files, the location of the data, and how to access the data.
Data Format and Projection
All vector data are delivered as Esri shapefiles in the geographic coordinate system (WGS84). The raster data are Esri binary grid format or GeoTiff in Universal Transverse Mercator projection, Zone 19N, WGS84 datum. All spatial data are distributed with Federal Geographic Data Committee (FGDC) compliant metadata in text and FGDC Classic and FAQ [in hypertext markup language(*.HTML)] formats. Esri ArcCatalog can also be used to examine the metadata available in the Esri XML format associated with each GIS data file.
Data Access
The datasets from this project can be accessed in the following ways, depending on available software:
With ArcGIS 9.3 or later, all shapefile and raster data may be viewed and manipulated, although the Spatial Analyst extension will be required to fully examine and work with the Esri grids. Copy the GIS_catalog folder or download the GIS_catalog.zip file (90 megabytes) to a computer and open the ArcMap document 2012-1157.mxd. This map document has all the data layers loaded in the table of contents and uses relative links.
Without any GIS software, view the data through ArcReader, a free mapping application distributed by Esri for Windows, Linux, and Unix operating systems. Download ArcReader from the Esri Web site (http://www.Esri.com/software/arcgis/arcreader/download.html) and follow the directions for downloading and installing the free software. Once ArcReader is installed, all the data can be viewed by opening the published map file (PFM) named 2012-1157.pmf, which was created in ArcMap version 9.3.1.
Data Organization
The data are organized in folders on the Publications Warehouse Web site. The file structure is the same for both media and is described below. Data layers can be downloaded individually using the table below or collectively from the GIS_catalog.zip file.
 GIS_catalog
The following is a listing of selected contents of the GIS_catalog.zip file:
Basemap
OUTLINE25K_POLY_dd.shp– Outline of the Commonwealth of Massachusetts (1:25,000)
PhysiographicZones
NAH_CCB_Pzones.shp– Shapefile: Physiographic Zones polygons defined through the interpretation of geophysical and sample data.
SedimentTexture
NAH_CCB_sedcover.shp– Shapefile: Sediment Texture polygons defined through the interpretation of geophysical and sample data.
SourceData
bathy
navd_bath_30m– Grid: Bathymetry at 30-m resolution.
NAVD88_HS_30m.tif– Image: Hillshaded relief image at 30-m resolution.
BScomposite_10m.tif– Image: Acoustic backscatter intensity mosaic at 10-m resolution.
Stratigraphy
Qfe
qfeiso– Grid: Isopach of Qfe stratigraphic unit at 50-m resolution.
Qm
qmiso– Grid: Isopach of Qmn and Qmd stratigraphic units at 50-m resolution.
Ur
surface
urelev– Grid: Elevation of Ur surface at 50-m resolution.
urelevhs.tif– Image: Hillshaded relief image of the Ur ravinement surface at 50-m resolution.
Ut
surface
utelev– Grid: Elevation of Ut surface at 50-m resolution.
utelevhs.tif– Image: Hillshaded relief image of the Ut ravinement surface at 50-m resolution.
SurficialGeology
Nahant_CCB_surfgeol.shp– Shapefile: Surficial geology as defined through the interpretation of seismic profiles
Map document:
2012-1157.mxd – ArcMap™ 9.2 map document containing selected data layers described above.
Data Preview
To download raster and vector data, right click on the link within the 'transfer file' column in the table below. 'Save Target As...' to save a compressed ZIP file to the local hard drive.
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U.S. Department of the Interior |
U.S. Geological Survey
