|
Are you looking for ENC®s for Navigation? Abstract NOAA Electronic Navigational Charts (ENCs) have been developed to support safe navigation in U.S. waters and are available for free download at NOAA ENC. The NOAA ENCs are in International Hydrographic Organization (IHO) S-57 format, which is the data standard developed by the IHO to be used for the exchange of digital hydrographic data. NOAA ENCs can also be used for non-navigational purposes in Geographic Information Systems (GIS). In order for NOAA ENCs to be used in GIS, the data must be translated from S-57 to a GIS-friendly format. The resulting data can be used for a variety of non-navigational purposes that involve geospatial analyses. Purpose The NOAA ENC Direct to GIS web portal provides comprehensive access to display, query, and download all available NOAA ENC data in a variety of GIS/CAD formats for non-navigational purposes using Internet mapping service technology. Nautical chart features contained within a NOAA ENC provide a detailed representation of the U.S. coastal and marine environment. These data include coastal topography, bathymetry, landmarks, geographic place names, and marine boundaries. Features in a single NOAA ENC are limited in that they only represent the geographic region that is depicted in that particular NOAA ENC cell. By aggregating nautical features from all NOAA ENCs in the creation of GIS data, a continuous depiction of the U.S coastal and marine environment is achieved. Basic structure of NOAA ENC data An ENC contains attributed vector spatial data of nautical chart features. Nautical chart features are organized in S-57 object classes. Attributes in an ENC further describe each nautical feature. Each ENC object class has predefined geometry types associated with it (e.g., point, line, area (polygon in NOAA ENC Direct to GIS)). For example, the land area object class has both point and polygon geometry. An ENC can contain any of the predefined IHO object classes and attributes. NOAA ENC® Direct to GIS Download All object classes (layers in the Internet mapping service) that are visible in your browser's view frame can be extracted and downloaded in a variety of GIS/CAD formats. For improved download speed, NOAA ENC Direct to GIS is designed to provide data in the geographic region of your view frame. If a feature extends beyond the view frame, the feature is clipped and exported to reflect what is in the view. This clipping function limits the extent of the data that can be extracted. Users can also retrieve features that are outside of the view frame by specifying the coverage area they are interested in through latitude and longitude key ins. By clicking the button below, I acknowledge that any data obtained from this service is not suitable, and should not be used, for navigation. For FGDC-compliant metadata about NOAA ENC Direct to GIS, please click here-- http://ocs-spatial.ncd.noaa.gov/encdirect/encdirect_met.htm. For technical or content questions about NOAA ENC Direct to GIS, please contact enc.gis@noaa.gov.
Revised Wednesday August 02 2006by OCS Webmaster |