|0||Short integer field where zeros are "no data" and automatically filled in for the remaining shoreline polylines not derived from lidar.|
|0||Zeros are "no data" and serve as place fillers for the lidar shorelines. Actual uncertainty values for lidar are stored in shoreline uncertainty dBase (.dbf) file.|
|Range of values|
|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.|
This dataset includes shorelines from 29 years ranging from 1851 to 1997 in the Delmarva South and Southern Virginia coastal region from Wallops Island, Virginia to the Virginia/North Carolina border. Shorelines were compiled from maps (U.S. Army Corps of Engineers Coastal Engineering Research Center), T-sheets (National Oceanic and Atmospheric Administration), T-sheets and air photos (Virginia Coast Reserve Long-Term Ecological Research Project), and lidar (USGS). 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 U.S. Geological Survey's (USGS) National Assessment Project. Rates of long-term and short-term shoreline change were generated in a GIS using the Digital Shoreline Analysis System (DSAS) version 4.1. 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.
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 as the originator of the 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 9.0) file contains a shapefile of historic shorelines from 1851 to 1997 for the sandy shorelines of Delmarva South and Southern Virginia from Gunboat Point, Virginia to the North Carolina border. in format Shapefile (version ArcGIS 9.3) ESRI polyline shapefile|
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.