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|Learn more about the new graphical interface in this video:
about using NOAA's ENC® Direct to GIS.
About NOAA's ENC® Direct to GIS [Top]
NOAA's Electronic Navigational Charts (ENC) Direct to GIS web portal provides comprehensive access to display and download all available NOAA ENC data in a variety of GIS/CAD formats for non-navigational purposes using web mapping service technology.
The NOAA ENC data 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. Nautical chart features contained within a NOAA ENC provide a detailed representation of the U.S. coastal and marine environment. This data includes coastal topography, bathymetry, landmarks, geographic place names, and marine boundaries. Features in a NOAA ENC are limited in that they only represent the geographic region that is depicted in that particular NOAA ENC. By aggregating nautical features from all NOAA ENCs in the creation of GIS data, a contiguous depiction of the U.S. coastal and marine environment is achieved.
To learn more about S-57, please visit the IHO website.
For additional help with this application, please visit our FAQ page.
For questions or comments, please contact us by submitting an online inquiry.
File Naming Conventions and Scale Bands [Top]
The NOAA ENC® Direct to GIS data is organized by scale band, and there are four scale bands available in the ENC Direct to GIS application. Those scale bands are Overview, General, Coastal, and Approach/Harbour. The scale ratio for each scale band is defined below:
- Overview scale band consists of ENC files with a scale band of 1:500,001 or smaller.
- General scale band consists of ENC files with a scale band from 1:1,500,000 – 1:600,001.
- Coastal scale band consists of ENC files with a scale band from 1:600,000 – 1:150,001.
- Approach/Harbour scale band consists of ENC files with a scale band from 1:150,000 or larger.
The ENC filename is stored in the attribute named DSNM from the “coverage_area” feature layer. The third character within the filename is a numeric value referencing to the following scale band category. For example, a filename of US2EC02M.000 indicates that it is within the General scale band category.
1 = Overview
2 = General
3 = Coastal
4 = Approach/Harbour
To learn more about the object attributes for each S-57 object, please visit the S-57 Object Catalogue available at the following links:
Using the Interface [Top]
The NOAA ENC® Direct to GIS application allows the user to view and download seamless ENC data by scale band. Please refer to the screenshot below for an image of the opening screen of the application.
ENC Scale Band: The text box named ‘ENC Scale Band’ located at the top of the screen allows users to turn on or turn off a particular scale band. Clicking the drop down arrow next to the scale band’s name provides several functionalities, such as changing dataset transparency or reading about the description of the dataset.
General: The ENC data can have an overlay, with three choices of base maps available from the top right corner of the screen. Those choices are world, ocean, and raster imagery. The lower right corner of the screen provides an overview of the area. Clicking the ‘arrow’ will expand and hide the overview insert. The left side of the screen contains the navigation bar, where users can zoom in, zoom out, and pan. The globe icon will bring the display extent back to the U.S. continental area. The lower left corner of the screen contains the scale bar and the display of the latitude and longitude values. Users can also click ‘More Information’ at the top right corner to get more information about the application.
Please note some data will not display on-screen until you have zoomed in to the appropriate level. However, when extracting data, all selected data in the scale band will be extracted whether visible on-screen or not.
Popup Window: The ENC Direct to GIS application also provides a popup information window that displays information for a particular ENC file. By clicking on the screen, a popup window will display the title of the ENC, the ENC filename, and the source indicator for the ENC file. This popup functionality is especially useful to identify the ENC filename or scale band of the data that the user is viewing when zoomed in to a large scale ratio.
Toolbar: The ENC Direct to GIS application also provides several functionalities allowing users to search, identify, print, or extract data. These are available from the toolbar located at the top of the application. Please see section ‘Using the Toolbar’ below for details.
Using the Toolbar [Top]
Bookmarks: There are a few pre-made bookmarks available with this tool. For example, clicking the Baltimore, MD, bookmark will bring the zoom extent to the Baltimore area. Users can add their own bookmarks by clicking the ‘Add Bookmark’ button. To add a bookmark:
1: Zoom to an area of interest.
2: Click the ‘Add Bookmark’ button and give your bookmark a name.
3: A new bookmark is now available. You may delete it at any time.
Search by Location: Users can enter the address or place name to locate an exact point on the map.
Draw and Measure: This tool allows users to measure area and distance in various unit types. The tool also allows users to add text to the screen or add a customized point shape to the screen. To draw and measure:
- Choose the type of drawing tool and other drawing options to be used.
- Check the 'Show Measurements' box and choose the units desired.
- Draw the line or polygon desired on the screen, covering the chosen area. The units/distance will show within the polygon or next to the line. The size and shape of the polygon can be adjusted on the screen by clicking the shape and moving the points. The area/distance units will automatically adjust to the new shape/size.
- To add additional text to the screen, click on the 'A' next to the polygon tools, then click in the 'Text' box and type. Then click on the screen where the text should be placed. To adjust the text positioning, click and hold the text and drag to the new location.
Print: The ‘Print’ tool allows users to print the current screen. Users can add a ‘Title’ and ‘Subtitle’ to the map. If users have Adobe installed, a PDF file can be printed as well.
Legend: The ‘Legend’ tool displays the symbols used for all of the features by scale band. If users turn off a particular ENC scale band from the ‘ENC Scale Band’ box located at the top right corner, the legend for that particular scale band will disappear from the legend window.
Data Extract: The ‘Data Extract’ tool allows users to extract ENC data by scale band. Please refer to the "How to Extract ENC data" instructions below for details.
How to Extract ENC data – an example [Top]
The ‘Data Extract’ tool allows users to extract ENC data by scale band. The tool doesn’t require the data to be visible on the screen. Users can extract data by drawing a polygon on the screen to define the area of interest. The ENC data will be clipped using this user-defined polygon. Users can select various output file formats, such as shapefile (.shp), geodatabase (.gdb), or various CAD file formats.
The following is an example of extracting data within the Overview scale band:
1: Click the ‘Data Extract’ tool to expand the four scale band choices: Overview, General, Coastal, and Approach/Harbour. Click ‘Extract Overview.’ See the screenshot:
2: The ‘Extract Overview’ window will popup. See the screenshot below. Follow these steps:
- In step ‘1. Select area,’ select a shape to draw a polygon on the screen. This will be used as a boundary to clip the ENC data.
- In step ‘2. Select layers to extract,’ click the appropriate boxes to select the desired feature layers to be clipped. The layers do not need to be visible on the screen to be extracted.
- In step ‘3. Select file format,’ choose the desired output file format.
- Click the ‘Extract’ button to extract the data.
Please note that if you select a feature layer to be extracted that has no data available, an empty layer will be created as output.
3: When the extraction is completed, the user will be prompted to save the output .zip file. See the screenshot below for an example:
4: The default output filename is ‘extractedData.zip’ – the user may rename it if desired. Please note that if the output .zip file is not renamed and another output .zip file is downloaded, the new output .zip file will override the previous output .zip file because they have the same default filename.
Follow the same procedure to extract data for other scale bands.
To access metadata for each layer by scale band:
1. Choose the base map you'd like to use - World, Ocean, or Raster.
2. From the box named ‘ENC Scale Band,’ click the drop down arrow next to the scale band’s name.
3. Choose ‘Description.’
4. A new browser window will show the description for the map service. Click on a layer to see metadata for a specific layer.
List of Services Available: [Top]
Rest URL for Map Services:
Rest URL for Geoprocessing Services:
Connect to the WMS [Top]
The ENC Direct to GIS application provides web map services (WMS) for each scale band. Users can connect to the WMS service using ESRI’s GIS desktop clients. Users can then overlay their own data on top of the ENC Direct WMS services. Follow instructions below to connect to the WMS service:
- In ESRI’s ArcCatalog, expand ‘Database Connections’ and GIS Servers.
- Choose ‘Add WMS Server.’
- Type the following address in the URL box to connect to the WMS for each scale band:
- After connecting to the WMS, the user can drag the service to ArcMap and overlay the ENC data with their own data in ArcMap.
Other Nautical Chart GIS resources [Top]
Contact Us [Top]
We want to hear from you. For questions or comments, please contact us by submitting an online inquiry at http://ocsdata.ncd.noaa.gov/idrs/inquiry.aspx?.
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