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Coverage

Continental U.S, with portions of Hawaii, Pacific Islands, Alaska, Puerto Rico, and the U.S. Virgin Islands

Source Data

National Shoreline vectors and non-NOAA sources including lidar, imagery, and existing cartographic data.

Tidal Datum

Where applicable, CUSP references mean high water based on vertical modeling or image interpretation using water level stations and/or shoreline indicators.

Scale

Variable; 1:1,000 – 1:24,000

Spatial Reference

Geographic coordinate system; horizontal datum – North American Datum of 1983 (NAD83).

Accuracy

Variable depending on source. This shoreline is not to be used for legal purpose since it includes shoreline compilation with less stringent data acquisition requirements and quality control measures as compared to the National shoreline.

Process Description

Individual national shoreline projects and high-resolution LiDAR-derived shoreline were merged to form the framework of this product. Individual projects are edge matched using contemporary imagery as a guide. Single-line alongshore features and alongshore features where water passes underneath are not included in in this shoreline data set. The current attributes include source id, data source, horizontal accuracy, information field, attribute name, image verification date, source resolution, data source, extraction method (mono versus stereo), and source citation. The shoreline will be updated without regard to maintaining versions. Limited shoreline updates to existing vectors may be edited using verification imagery when the vectors and the imagery register well together, or when the updated vectors can be shifted to existing accurate vectors. Once verification imagery meets the accuracy criteria stated above, the decision to compile features is based on the ability to extract a proxy mean high water line considering water level, image date, resolution, accuracy, and shoreline slope. New shoreline compilation from contemporary commercial satellite and othomosaic imagery may be used to compile new shoreline based on those same considerations. CUSP shoreline emphasizes the most current temporal positioning versus the most accurately acquired data. The mapping of the most current temporal positioning of the proxy mean high water for this product excludes the effects of seasonal (summer versus winter beaches) and storm response (northeasters and hurricanes) on spatial variability of beach morphology.

Continually Updated Shoreline Product (CUSP)

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