Chart Correction
The nature of a waterway depicted by a chart may change, and artificial aids to navigation may be altered at short notice. Therefore, old or uncorrected charts should never be used for navigation. Every producer of nautical charts also provides a system to inform mariners of changes that affect the chart. In the United States, chart corrections and notifications of new editions are provided by various governmental agencies by way of Notice to Mariners, Local Notice to Mariners, Summary of Corrections, and Broadcast Notice to Mariners. In the U.S., NOAA also has a printing partner who prints the "POD" (print on demand) NOAA charts, and they contain the very latest corrections and notifications at the time of printing. Radio broadcasts give advance notice of urgent corrections.
A good way to keep track of corrections is with a Chart and Publication Correction Record Card system. Using this system, the navigator does not immediately update every chart in the portfolio when a new Notice to Mariners arrives, instead creating a card for every chart and noting the correction on this card. When the time comes to use the chart, he pulls the chart and chart's card, and makes the indicated corrections on the chart. This system ensures that every chart is properly corrected prior to use. A prudent mariner should obtain a new chart if he or she has not kept track of corrections and his chart is more than several months old.
Various Digital Notices to Mariners systems are available on the market such as Digitrace (http://www.marinepress.com/mpc/index.html), Voyager (www.tgnsvoyager.com), ChartCo (www.http://www.chartco.com/) to correct British Admiralty charts as well as NOAA charts. These systems provides only vessels relevant corrections via e-mail or web downloads reducing time needed to sort our correction for each chart. Also, tracings to assist corrections are provided at the same time.
The Canadian Coast Guard also produces the Notice to Mariners publication which informs mariners of important navigational safety matters affecting Canadian Waters. This electronic publication is published on a monthly basis and can be downloaded from the Notices to Mariners (NOTMAR) Web site. The information in the Notice to Mariners is formatted to simplify the correction of paper charts and navigational publications.
Various and diverse methods exist for the correction of electronic navigational charts.
Read more about this topic: Nautical Chart
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