NOAA Shoreline Website

A Guide to National Shoreline Data and Terms

NOAA National Shoreline

Purpose and Potential Application: This shoreline was originally intended to support NOAA nautical chart production. Other applications include shoreline change analysis, boundary determination, and cartographic representation.

Originator(s): National Oceanic and Atmospheric Administration (NOAA) National Geodetic Survey (NGS)

Abstract: These shoreline data represent a vector conversion of NOAA National Ocean Service (NOS) raster shoreline manuscripts (T-sheets) and aerial imagery from the year 1855 to the present.

Access: NOAA Shoreline Data Explorer

Scale(s): 1:5,000 to 1:20,000

Coverage: Continental U.S., with Washington, Maine, and the Great Lakes only partially represented; Hawaii and portions of Alaska, Puerto Rico, and the U.S. Virgin Islands are also included.

Source Data: NOAA shoreline manuscripts (T-sheets) and aerial imagery

Spatial Reference: Geographic coordinate system (decimal degrees); Horizontal Datum – North American Datum of 1983 (NAD83)

Tidal Datum: Mean high water (MHW) and mean low low water (MLLW)

Data Format: ESRI shapefile. Data is distributed by project area. Projects are defined by geographic location and time period. The shoreline is seamless within each project.

Accuracy:Vector data were derived from rectified raster images of NOS coastal survey maps using ArcInfo processing software. Vector shoreline extracted from map images adequately represents the shoreline shown on original NOS source surveys. The absolute value of the overall predicted horizontal accuracy has not been determined. However, the reports associated with the project maps describe the process of producing the map source and include the horizontal control layout and, if aerotriangulated, the fit-to-control statistics. One may refer to the March 6, 1991, edition of the Journal of Coastal Research for an article entitled "Historical Shoreline Change: Error Analysis and Mapping Accuracy" for an independent accuracy assessment of vectorized NOS digital shoreline conducted by the Federal Emergency Management Agency and the University of Maryland.

Process Description: These data are derived from shoreline maps that were produced by NOS, including its predecessor agencies, and were based on analysts’ interpretations of imagery or field surveys. The NGS attribution scheme, "Coastal Cartographic Object Attribute Source Table (C-COAST)," was developed to synthesize the attribution of various sources of shoreline data into one attribution catalog. C-COAST is not a recognized standard but was influenced by the International Hydrographic Organization's S-57 Object-Attribute standard so the data would be more accurately translated into S-57.2

During the vectorization process, all adjoining shoreline maps in the project are displayed on a computer screen, and the shoreline is traced and coded appropriately. Maps within a project generally adjoin and, therefore, there is significant agreement of line work across the borders of the shoreline maps. This results in fewer errors related to the edge-matching process. Polygon labels and attributes are assigned to features containing area so that users may shade the data to determine land, water, or man-made features. All lines were attributed with feature code values that were translated to conform to NGS's Coastal Cartographic Object Attribute Source Table attribution scheme.

Point of Contact:
Doug Graham
NOAA National Geodetic Survey
(301) 713-2676, ext. 170

Other References: