OVERVIEW

NOAA nautical charts are a graphic representation of a maritime area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land (topographic map), natural features of the seabed, details of the coastline, navigational hazards, locations man-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and man-made structures such as harbors, buildings and bridges.

In the United States, all official nautical paper charts produced by NOAA's Office of Coast Survey (OCS) are available in raster format. A fundamental tool of marine navigation, NOAA's Raster Navigational Charts (NOAA RNCs) are produced by scanning at high resolution the original color separates, which are used to print the paper charts. NOAA adds to the digital raster file such features as data describing the chart, its datum, projection, and its geo-reference. Geo-referencing enables a computer-based navigation system that is connected to a GPS to locate and display on the chart image on screen the vessel's exact position.¹

DISCLAIMER: It is important to note that these images alone should not be used for navigational purposes. Because of potential updates and limitations on scale, the NOAA Raster Navigational Chart data distributed by MassGIS should be used primarily as a backdrop display,  for plotting vector data, and for interpretation and analysis. Mariners should always consult Coast Pilots and local port authorities and harbormasters and check water and weather conditions. MassGIS, the Commonwealth of Massachusetts, and the Executive Office of Energy and Environmental Affairs do not assume responsibility for the improper use of these data.

In ArcSDE the 67 chart images are named NOAA_<chart #>_<quantity>, in the NOAA schema. The "chart #" is the five-digit number assigned by NOAA. Following the chart number and an underscore character is a number indicating the quantity of images produced from each RNC (some maps have one or more insets and/or sections of the main map, and each is included as its own image). Two additional images, with a "_TC" suffix, are not charts but digital versions of tide charts and other textual information for the small craft operator.

A vector index layer was created from the footprints of each image in ArcGIS. This layer, named NOAA_INDEX_POLY in the NOAA schema in ArcSDE, may be used to reference the location of each chart.

Please note that the August 2008 release of these images replaces the older, less spatially accurate images produced by MassGIS by scanning paper copies of NOAA Nautical Charts.

MassGIS received the images from NOAA, via the Massachusetts Office of Coastal Zone Management. MassGIS imported the rasters into its ArcSDE database and projected each to the NAD83 Mass. State Plane Mainland Meters coordinate system. The images are otherwise unchanged. For information on the processing used by NOAA to produce the original RNCs see http://nauticalcharts.noaa.gov/mcd/Raster/index.htm. Note that the new images include the "collars" -- the borders and other non-data areas (text, etc.) that appear on each chart. In the previous set MassGIS had clipped off the collars, which on the new images will obscure parts of adjacent or overlapping charts. See the "Displaying the Images" section below for more details.

To produce the index layer, the ArcGIS Raster to Polygon tool was used to create a polygon representing the outline of each chart image. All the polygons were then merged into a single polygon feature class.

MassGIS makes available an ArcGIS 9.2 file geodatabase named NOAA_CHARTS.gdb containing all 69 images.

The following table lists the image number, chart title and original paper map scale and edition date (last updated by NOAA) for all the images in this layer.
 

Image No.	Chart Title	Scale	Edition Date
13006_1	West Quoddy Head To New York	675000	2007-05-01
13009_1	Gulf Of Maine And Georges Bank	500000	2007-05-01
13200_1	Georges Bank And Nantucket Shoals	400000	2007-05-01
13203_1	Georges Bank Western Part	220000	1999-08-14
13204_1	Georges Bank Eastern Part	220000	1999-08-14
13218_1	Martha's Vineyard to Block Island	80000	2008-02-16
13221_1 13221_2_TC	Narragansett Bay Additional information (tide charts, etc.) for the small craft operator	50000 --	2006-06-17
13224_1 13224_2	Providence River and Head of Narragansett Bay Seekonk River, Cold Spring Point to Pawtucket	20000 20000	2006-11-01
13226_1 13226_2	Mount Hope Bay Continuation of Taunton River	20000 20000	2004-01-01
13227_1 13227_2	Fall River Harbor State Pier	10000 2500	2006-03-01
13228_1	Westport River And Approaches	20000	1997-05-17
13229_1 13229_3 13229_4 13229_6 13229_7 13229_8 13229_9 13229_10 13229_11 13229_12 13229_13 13229_14 13229_15_TC	South Coast of Cape Cod and Buzzards Bay (Barnstable-Chatham) South Coast of Cape Cod and Buzzards Bay (Inset-Hyannis Harbor) South Coast of Cape Cod and Buzzards Bay (Gosnold-Barnstable) South Coast of Cape Cod and Buzzards Bay (Inset-Woods Hole) South Coast of Cape Cod and Buzzards Bay (Inset-Robinsons Hole) South Coast of Cape Cod and Buzzards Bay (Inset-Cuttyhunk Harbor) South Coast of Cape Cod and Buzzards Bay (Gosnold) South Coast of Cape Cod and Buzzards Bay (Dartmouth-Falmouth) South Coast of Cape Cod and Buzzards Bay (N Buzz Bay) South Coast of Cape Cod and Buzzards Bay (New Bedford Harbor) South Coast of Cape Cod and Buzzards Bay (Cape Cod Canal) South Coast of Cape Cod and Buzzards Bay (Inset-Prince Cove) Tide prediction chart	40000 20000 40000 5000 12000 12000 40000 40000 40000 20000 40000 --	2004-12-18
13230_1 13230_2	Buzzards Bay Quicks Hole	40000 20000	2005-10-01
13232_1 13232_2	New Bedford Harbor and Approaches Continuation of Apponagansett Bay	20000 20000	2001-06-30
13233_1 13233_2	Marthas Vineyard Menemsha Pond	40000 20000	2005-09-01
13235_1	Woods Hole	5000	2004-04-01
13236_1 13236_2	Cape Cod Channel And Approaches	20000 20000	2006-03-01
13237_1	Nantucket Sound And Approaches	80000	2007-03-01
13238_1 13238_2 13238_4	Marthas Vineyard - Eastern Part Oak Bluffs Harbor Edgartown Harbor	20000 10000 10000	2007-08-01
13241_1	Nantucket Island	40000	2005-11-01
13242_1	Nantucket Harbor	10000	2001-05-26
13244_1	Eastern Entrance To Nantucket Sound	40000	2005-07-01
13246_1	Cape Cod Bay	80000	2006-12-01
13248_1	Chatham Harbor And Pleasant Bay	20000	2001-03-17
13249_1	Provincetown Harbor	20000	2007-04-01
13250_1	Wellfleet Harbor	40000	2001-10-13
13251_1	Barnstable Harbor	20000	2004-09-01
13253_1	Harbors of Plymouth, Kingston And Duxbury	20000	2005-07-01
13260_1	Bay Of Fundy To Cape Cod	378838	2005-07-01
13267_1 13267_2	Massachusetts Bay North River	80000 20000	2005-07-01
13269_1	Cohasset And Scituate Harbors	10000	2006-02-01
13270_1	Boston Harbor	25000	2006-06-01
13272_1 13272_2	Boston Inner Harbor Mystic River Extension	10000 10000	2004-10-01
13274_1 13274_2 13274_3 13274_4 13274_5	Portsmouth Harbor to Boston Harbor (Hampton-Rockport) Portsmouth Harbor to Boston Harbor (NH coast) Merrimack River Extension Merrimack River Extension Portsmouth Harbor to Boston Harbor (Rockport-Boston)	40000 40000 80000 80000 40000	2007-06-01
13275_1 13275_2	Salem and Lynn Harbors Manchester Harbor	25000 10000	2006-06-23
13276_1	Salem, Marblehead and Beverly Harbors	10000	2003-07-01
13278_1 13278_2	Portsmouth To Cape Ann Hampton Harbor	80000 30000	2005-06-01
13279_1	Ipswich Bay To Gloucester Harbor	20000	2007-02-01
13281_1	Gloucester Harbor And Annisquam River	10000	2007-02-01
13282_1	Newburyport Harbor and Plum Island Sound	20000	2003-04-01

Chart numbers 13203, 13224, 13229, 13232, 13242 and 13274 were not included in the previous set of images. Chart number 13003 is not included in the new set.

The images files do not contain attributes. Sounding values on the images with scales 2,500 - 80,000 are in feet at mean low water. Soundings on smaller scale maps are in fathoms.

The NOAA_INDEX_POLY attribute table for the index layer contains the following items:
 

ITEM NAME		DESCRIPTION
IMAGE_NAME		Name of image, as stored at MassGIS. Includes the 5-digit chart number assigned by NOAA.
CHARTTITLE		NOAA Chart Title
SCALE		Scale of chart (as it appears on each image)
ED_DATE		Chart Edition Date

Public distribution of these data include:

• NOAA_CHARTS.gdb - ArcGIS 9.2 file geodatabase with all 69 images. Available as a digital data product on the online order form.
  
• MrSID files - Free download of all 69 images in the MrSID file format. May be displayed in many GIS software products. Also available as a digital data product on the online order form. Included ArcGIS 9.0/9.1 layer files for use with stand-alone ArcMap and with the MassGIS Data Viewer.

DISCLAIMER, from the NOAA RNC User Agreement:
Limitations on Use: NOAA RNCs™ may be redistributed, but redistributed NOAA RNCs™ are NOT considered official NOAA RNCs™, and do not meet federal chart carriage regulations for regulated vessels. This official status attends only to the original downloaded files. At a future date, NOAA intends to establish a program under which distributors may be certified to redistribute NOAA RNCs™ such that they will retain their official status and meet chart carriage regulations.

As noted above, because these images include the map collars, displaying adjacent or overlapping charts will not be seamless. With the geodatabase version in ArcMap, choosing to display "nodata" and Color Index value 1 (white) as 'No Color' will minimize the effect of the collars. In the MrSID files,black "nodata" areas appear around the edges; displaying "nodata" as 'No Color' will partially minimize these areas. Also, some ArcMap users may want to choose to resample during display using Bilinear Interpolation for a smoother, more readable appearance (set this in the image layer's properties Display tab). The layer files available for download and included on the MrSID CD product include the bilinear resampling and layer titles as  listed in the table above.

When using these NOAA Chart images, it may be helpful to refer to NOAA's "Office of Coast Survey" and "Navigational Charts" pages, which contain a multitude of links, including user manuals, map symbol descriptions and more.

MassGIS does not sell or distribute paper copies of the NOAA Nautical charts. Such maps may be viewed at some major libraries and are for sale from Authorized Nautical Chart Sales Agents and other vendors.

The National Ocean Service Mapfinder and Free Boating Charts Web sites provide online viewing of NOAA Chart images.

¹ http://nauticalcharts.noaa.gov/mcd/Raster/index.htm

Last Updated 9/12/2008
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