NOAA's Raster Navigational Charts (RNCs) are produced by NOAA’s Office of Coast Survey (OCS) and are designed for marine navigation, but can also be used as a marine base map by GIS users, coastal and ocean planning staff, and the general public. The charts provide a consistent view of the marine environment, but with more than 2,100 individual chart and inset files available, finding the right chart at the right scale can be time consuming.
In response, the Special Projects Division has created a map service of all 2,100+ raster navigational charts and their insets. The charts display as a seamless mosaic with the map collar or neat line—the information around the chart providing scale and notes—removed. Also, the map service displays only those charts appropriate for the viewing scale and map extent requested. This ready-to-use map service lets both GIS and non-GIS users see chart information in the context of their own data, without having to download and integrate multiple charts for their area of interest.
The seamless NOAA RNCs within the Web map service are updated monthly and represent the most recent version of the RNCs and their respective Notices to Mariners (NtMs) at the time of the update.
Additional information on the NOAA RNCs can be found at NauticalCharts.noaa.gov.
Web Map Services for the RNCs
The Seamless RNCs are served through Esri’s GIS Image Extension product. Chart display order and visibility are determined by Esri algorithms that display the appropriate chart. Chart draw order is determined by the area of the chart, and charts with a smaller area have display order precedence over charts with a larger area. Only official charts from OCS may be used for navigation. The charts in this map service, though derived from official charts, are not to be used for navigation.
This is the Seamless RNC Server Esri REST service page.
When using the Web service in ArcMap or programming via the Esri API, advanced query and display capabilities are available. All attributes of the charts are available for feature selections using the Definition Query of the Layer Properties. Entering a query of “CHART_NUM='14912_2'” will display the collarless version of that single chart.
Using the Raster Navigational Charts Google Earth Tool
A Google Earth file of all the charts and insets is also available and is updated monthly along with the map service updates. Clicking on a chart outline gives you information about that chart, such as title, scale, and date updated. Plus, you have the option to overlay in Google Earth a collared or a collarless version of the chart by clicking on the respective preview link. http://nosimagery.noaa.gov/rnc/NOAA_RNCs.kmz
To find a specific chart, click on the magnifying glass and enter the chart number:
After a chart has been previewed, the opacity can be changed to allow the imagery to show through by clicking the opacity button and adjusting the slider:
A layer in the Google Earth file—“Seamless NOAA RNCs”—makes a request to the map server for a single image of the charts within the view. This view provides the best results when the view is straight down—an angled view of the Earth will request a large geographic area with a number of pixels too few to be readable.
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