USGS National Assessment of Shoreline Change Vector Shorelines
Purpose and Potential Applications: These high-resolution historical and modern vector shorelines were primarily created for use in detailed shoreline change analyses.
Originator(s): The U.S. Geological Survey
Abstract: The U.S. Geological Survey (USGS) produced a comprehensive database of digital vector shorelines by compiling shoreline positions from pre-existing historical shoreline databases and by generating historical and modern shoreline data. Shorelines are compiled by state and generally correspond to one of four periods: 1800s, 1920s-1930s, 1970s, and 1998-2002. Each shoreline may represent a compilation of data from one or more sources for one or more dates provided by one or more agencies.
Access:
To Download the Data
- U.S. Mid-Atlantic and New England
- U.S. Southeast Atlantic
- U.S. Gulf of Mexico
- California Coast
To View the Data
Analysis Reports
- U.S. Mid-Atlantic and New England
- U.S. Southeast Atlantic
- U.S. Gulf of Mexico
- California Coast
Scale(s): 1:5,000 to 1:20,000
Coverage: Open-ocean shoreline along the U.S. Gulf of Mexico, Southeast Atlantic, and California, with development continuing for the Northeast Atlantic and the Pacific Northwest. Gaps in this data, if applicable, are a consequence of non-existing data or existing data that did not meet quality assurance standards.
Source Data: Details regarding the source are provided in the "Data Quality Information" section of the shoreline metadata; however, in general the historical shorelines are derived from NOAA T-sheets that were vectorized by a variety of agencies, and then compiled by USGS by state and time period. The lidar data were collected in collaboration with NASA using the NASA Airborne Topographic Mapper.
Spatial Reference:Geographic coordinate system (decimal degrees); Horizontal Datum: North American Datum of 1983 (NAD83)
Tidal Datum: Mean high water (MHW)
Data Format: ESRI shapefile. Shorelines are not seamless and are distributed as zip files can be downloaded by state.
Accuracy: Horizontal accuracy varies by location of shoreline and source data. See shoreline metadata for specific details.
Process Description:
Historic Shorelines: Shorelines from one or more sources were sought in an effort to develop a single shoreline for each period. Digital shorelines, if available from another agency, were acquired. If no digital shorelines were available, or if a data set was incomplete, T-sheets were requested from NOAA and received as scanned raster images. T-sheets were georeferenced using ERDAS IMAGINE geographic imaging software. Some T-sheets may have required additional coordinate transformation information from NOAA to account for datum offsets between historical datums (U.S. Standard Datum) and modern datums (North American Datum of 1927 or 1983). Datum transformations were applied to ground control point coordinates before registration. Total root mean square error for the rectification process was maintained below 1 pixel, which translates to approximately 4 meters at a scale of 1:20,000 and 1.5 meters at a scale of 1:10,000. Georeferenced T-sheets were loaded in ArcView, and vector shorelines were digitized. Quality assessments were performed and shorelines were edited to remove any overlap between adjacent shorelines. No edgematching between adjacent shorelines was attempted.
Modern Shorelines (lidar derived): The USGS, in collaboration with NASA, used the NASA Airborne Topographic Mapper (ATM II and III). The raw data were georeferenced at elevation points every few square meters. The data were then converted to North American Datum of 1983 and North American Vertical Datum of 1988. The shoreline generation involved an analysis of shore-normal profiles at 20-meter intervals alongshore. First, a shore-parallel reference line was digitized as a permanent baseline for any future shoreline generation. Profiles were assessed at 20-meter intervals perpendicular to the reference line. Each profile consisted of a 4-meter-wide swath of data points. An algorithm determined the shoreline position for each profile based on a regression fit through the foreshore of the profile. The function was evaluated at the mean high water (mhw) level to identify the horizontal position of the shoreline. The shoreline point solutions were then quality checked in ArcView GIS software against a gray scale elevation grid of the same data. Point solutions were connected to produce a continuous vector shoreline in shapefile format.
Point of Contact:
Rob Thieler
U.S. Geological Survey
rthieler@usgs.gov
(508) 457-2350
Other References:
- "Extracting Shorelines from NASA Airborne Topographic Lidar-Derived Digital Elevation Models," U.S. Geological Survey, Open-file report 2005–1427
- "An Operational Mean High Water Datum for Determination of Shoreline Position from Topographic Lidar Data," U.S. Geological Survey, Open-file Report 2005-1027
- Stockdon, H.F., A.H. Sallenger, J.H. List, and R.A. Holman. 2002. "Estimation of Shoreline Position and Change Using Airborne Topographic Lidar Data." Journal of Coastal Research. Volume 18, Number 3. Pages 502 to 513.