|0||Zeros are considered "no data" if a shoreline uncertainty table is detected (otherwise the default uncertainty value set by user in DSAS default parameters is used), additional positional uncertainty information associated with the lidar data is pulled from the shoreline_uncertainty.dbf table and is referenced in the process steps.|
|Range of values|
|0||Shoreline month and day are known.|
|1||Shoreline month and day are unknown and default value of 07/01 was used.|
|Range of values|
This dataset includes shorelines from 161 years ranging from 1847 to 2008 within the Boston coastal region from Carson Beach in South Boston to Weymouth River, including the Boston Harbor Islands. Shorelines were compiled from T-sheets and air-photos obtained from the National Oceanic and Atmospheric Administration (NOAA) and the Massachusetts Office of Coastal Zone Management (MA CZM). Historical shoreline positions serve as easily understood features that can be used to describe the movement of beaches through time. These data are used to calculate rates of shoreline change for the MA CZM Shoreline Change Project. Rates of long-term and short-term shoreline change were generated in a GIS using the Digital Shoreline Analysis System (DSAS) version 4.3. DSAS uses a measurement baseline method to calculate rate-of-change statistics. Transects are cast from the reference baseline to intersect each shoreline, establishing measurement points used to calculate shoreline change rates. For publication purposes, the shoreline data for Massachusetts were organized by region in order match the extent of previously published uncertainty files used in shoreline change calculations.
Are there legal restrictions on access or use of the data?
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, the Massachusetts Office of Coastal Zone Management and the Woods Hole Oceanographic Institution Sea Grant Program as the originators of this dataset.
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.
|Data format:||This WinZip (version 16.5) file contains a shapefile of compiled shorelines for the Boston region of Massachusetts. in format Shapefile (version ArcGIS 10) Esri polyline shapefile Size: 1|
This zip file contains data available in Environmental Systems Research Institute (Esri) polyline shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from Esri at www.esri.com.