Ocean Pilot Charts
F5. The Reference Layer: Glossary, Units, Signals and Information SourcesDefinition
Climatological pilot charts published by NGA.
Pilot charts are monthly climatological routing charts showing prevailing winds, currents, ice limits, gale frequencies, magnetic variation, and recommended great-circle tracks for an ocean region. The series originated with Matthew Fontaine Maury’s wind and current charts at the US Navy Hydrographic Office in the 1840s. Today they are published by NGA (formerly NIMA/DMA) for US waters and reproduced from data also held by NOAA; the Admiralty issues a parallel Routeing Charts series. Navigators use them for seasonal voyage planning, not for precise position-fixing.
Source: NGA Pilot Charts (Atlas of Pilot Charts), derived from M.F. Maury, US Navy Hydrographic Office wind and current charts (from 1847).