NOAA Office of Coast Survey (OCS) Shorelines
Purpose and Potential Applications: The main purpose of extracted vector shoreline (EVS) and electronic navigational chart (ENC) shoreline is to provide accurate shoreline data for public use. Other applications include cartographic representation and boundary determination. These shorelines are not intended for navigational uses or to be used as the legal shoreline.
Originator(s): National Oceanic and Atmospheric Administration (NOAA), Office of Coast Survey (OCS)
Abstract: NOAA OCS provides two digital vector shorelines that are each extracted from large-scale NOAA nautical charts. The EVS is not tidally referenced, since it represents the land area (buff tint) on nautical charts and excludes marsh areas (green tint). The ENC shoreline is collected for navigable waters and more accurately depicts the tidally influenced shoreline, including waterways and tidal creeks, since it corresponds to the black line seen on the nautical charts.
This shoreline can be downloaded as a single national merged data set, or by state or region.
Follow these steps to download the shoreline:
- Use the Zoom and Pan tools to navigate to your area of interest.
- Click the Extract button to begin the download process. A new window titled "NOAA's ENC Direct to GIS Data Order Form" will appear.
- Leave the default for the Extent. These lat/longs will correspond to the bounding coordinates of the viewable area of the map.
- Select desired download format.
- Select desired coordinates (most likely to remain default).
- Click Translate Data. A separate window will open allowing you to download the file to your computer in .zip format.
- Go to the location where you saved the file and unzip the file. Filenames preceded by “APPROACH_HARBOR” represent the highest resolution shoreline from large-scale charts. Filenames preceded by “COASTAL,” are shorelines derived from smaller scale regional charts.
Scale: Variable scale based on charts with 1:10,000 to 1:80,000 scales
EVS: Continental U.S., including the Great Lakes, Hawaii, Alaska, Puerto Rico, the U.S. Virgin Islands, and other U.S. trust territories and Caribbean and Pacific islands.
ENC: Available in many formats, such as ESRI shapefile, AutoCAD, and Google KML. Shorelines are not seamless and are distributed as line files downloadable by a user-specified extent.
Source Data: NOAA nautical charts
Spatial Reference: Geographic coordinate system (decimal degrees); Horizontal Datum – North American Datum of 1983 (NAD83)
EVS: not tidally referenced
ENC: Mean high water (MHW)
EVS: ESRI shapefile. Shorelines are distributed as a seamless line file can be downloaded by state, geographic region, or as a single merged file of the Continental US and territories.
ENC: ESRI shapefile. Shorelines are not seamless and are distributed as line files can be downloaded by a user-specified extent.
Accuracy: Nautical charts are updated as part of an ongoing process to create a cartographic representation of the best available data collected over the years, employing a variety of data collection technology and techniques and provided to the Office of Coast Survey using many scales, datums, and projections. Although technology has allowed for a drastic increase in positional accuracy, historical data have not been superseded for many areas. The data accuracy of the extracted vector products is checked against its source nautical chart only. It is in no way intended for navigational purposes.
EVS: This shoreline was extracted from raster nautical charts using a process and software developed by the NOAA OCS Cartographic and Geospatial Technology Program (CGTP). CGTP began developing and perfecting the automated system of charted shoreline extraction using MicroStation and ArcView. This was accomplished by using the same 762 dpi binary raster files that are in chart production. Lines were extracted from the land (buff tint) plates, allowing the entire chart to be collected in a matter of minutes. Next the lines were manually inspected for quality using the raster nautical chart, and modifications were made, if necessary. Those lines were then converted from the paper-charted units to geographic positions and imported to the ArcView Shape file format. Another quality-control inspection was made on the final files using the original raster nautical chart. The EVS is not currently maintained and may not reflect the shoreline on the latest edition paper chart.
ENC: The NOAA ENC database has been built from a combination of charted information, as well as original "source" information. NOAA has compiled critical features such as channel limits, aids to navigation, and obstructions from the original documents that were used to put the features on the paper chart. The objective is to use the most accurate information for features that are critical to the safety of navigation. NOAA uses a number of sources in compiling NOAA ENCs, including U.S. Army Corps of Engineers surveys, drawings, and permits, U.S. Coast Guard Local Notices to Mariners, National Imagery and Mapping Agency Notices to Mariners, NOAA hydrographic surveys, and the largest scale paper chart of an area. ENC Direct to GIS data were created by transforming Approach and Harbor, Coastal, General, Overview, NOAA ENC version 2 cells to ESRI's shapefile format using Safe Software's Feature Manipulation Engine. The ENC shoreline corresponds to the black line (approximate mean high water) seen on the nautical charts.
Point of Contact:
NOAA Office of Coast Survey
(301) 713-2645 x143