New Information Added to Charts
New data for chart updates is prioritized as being either “critical” or “routine.” Critical data includes any changes that may pose a danger to navigation and that mariners should be informed of as soon as possible. This includes, but is not limited to changes to the position or characteristics of aids to navigation (buoys, beacons, and lights), newly discovered rocks, wrecks, shoals, or other dangerous obstructions, and changes to the shape or minimum depths of federally maintained channels.
These “critical corrections” are published by the U.S. Coast Guard in Local Notices to Mariners and must be applied by hand to paper nautical charts to keep them up to date. However, any new paper chart purchased and any other raster chart format downloaded, will have all critical corrections already applied as of the week it is obtained.
All non-critical data is categorized as routine. This includes the results of ordinary hydrographic and shoreline surveys, which could be extensive, but have not identified any immediate dangers. In the past, this data was only available when a full new edition of a raster chart was published. Now, routine corrections are included in weekly updates, as soon as the new information is compiled.