Rates of cliff erosion were generated in a GIS using the Digital Shoreline Analysis System (DSAS) version 3.2; An ArcGIS extension for calculating shoreline change: U.S. Geological Survey Open-File Report 2005-1304, Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Miller, T.M. The extension is designed to efficiently lead a user through the major steps of shoreline change analysis. This extension to ArcGIS contains three main components that define a baseline, generate orthogonal transects at a user-defined separation along the coast, and calculate rates of change (linear regression, endpoint rate, average of rates, average of endpoints, jackknife).
Historical cliff erosion is considered to be a crucial element in studying the vulnerability of the national coastline. These data are used in a cliff erosion analysis for the USGS National Assessment Project.
publication date
Public domain data are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey (USGS) must be referenced as the originator of the dataset in any future products or research derived from these data.
USGS Patuxent Wildlife Research Center
University of Rhode Island
317 Woodward Hall, Dept. of Geosciences
The attributes in this dataset are based on the Digital Shoreline Analysis System (DSAS) version 3.2; An ArcGIS extension for calculating shoreline change (Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Miller, T.M. 2005. U.S. Geological Survey Open-File Report 2005-1304). The data has gone through a series of QA/QC procedures, and is therefore believed to accurately reflect the data gathered as part of the National Assessment of Shoreline Change Study.
Cliff edge-transect intersections represent the absolute position of the intersects. No additional checks for topological consistency were performed on the data.
This cliff edge-transect intersect data adequately represented the intersect at the time of the analysis. Remaining gaps in this data, if applicable, are a consequence of non-existing data, transects crossing man-made features or existing data that did not meet quality assurance standards.
Postional Accuracy is based on position of cliff edge with respect to the transect.
A baseline was manually constructed seaward of, and parallel to, the trend of cliff edges representing two general time periods (1920s-1930s and 1998-2002). Using DSAS an Extension for ArcGIS (http://pubs.usgs.gov/of/2005/1304/), transects were generated with a spacing of 20m and transect-cliff edge intersection points were saved to a separate layer. Transects were manually eliminated to prevent calculation of rates in areas where less than two cliff edges were intersected. Rates of cliff erosion, in units of m/yr, were calculated at each transect using end point analysis applied to both cliff edge positions. Uncertainties for the long-term rates are also reported in units of m/yr.
USGS Patuxent Wildlife Research Center
University of Rhode Island
Coastal Field Station
317 Woodward Hall, Dept. of Geosciences
Data were projected from UTM zone 10 to geographic Tool: ArcGIS > ArcToolbox > Toolboxes > Data Management Tools > Project Command issued: ['GCS_North_American_1983',DATUM['D_North_American_1983',SHPERIOD['GRS_1980',6378137.0,298.25722101]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]]
384 Woods Hole Road
Internal feature number.
ESRI
Distance from Baseline to Cliff Edge-Transect Intersect
U.S. Geological Survey
Feature geometry.
ESRI
Baseline ID Used by Transect
U.S. Geological Survey
Sequentially numbered values for each transect alongshore
U.S. Geological Survey
Time stamp for when DSAS computed statistics
U.S. Geological Survey
Indicates if transect was automatically generated or manually edited
U.S. Geological Survey
Start x-coordinate for transect position
U.S. Geological Survey
Start y-coordinate for transect position
U.S. Geological Survey
End x-coordinate for transect position
U.S. Geological Survey
End y-coordinate for transect position
U.S. Geological Survey
Angle of transect with respect to north (0/360 equals North) with values increasing clockwise
U.S. Geological Survey
Endpoint rate in meters/year.
U.S. Geological Survey
Length of feature in internal units.
ESRI
Pacific Science Center
400 Natural Bridges Drive
Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, these data and information are provided with the understanding that they are not guaranteed to be usable, timely, accurate, or complete. Users are cautioned to consider carefully the provisional nature of these data and information before using them for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user. Neither the U.S. Government nor any agency thereof, 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 data, software, information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. Trade, firm, or product names and other references to non-USGS products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy.
ESRI Polyline Shapefile. The DBF file contains the attribute data in dBASE format. The PRJ file contains the coordinate system information. The SBN and SBX files contain the spatial index of the geospatial data. The SHP file contains the geospatial data. The SHX file contains the index of the geospatial data. The XML file contains the metadata describing the data set.
USGS Patuxent Wildlife Research Center
University of Rhode Island
Coastal Field Station
317 Woodward Hall, Dept. of Geosciences