pilot chart

noun

1. any of a number of charts issued to mariners by the U.S. Hydrographic Office and showing meteorological, hydrographic, and navigational conditions prevailing, or likely to prevail, subsequent to the date of issue in some part of the world: issued monthly for most areas.
2. a chart giving information on atmospheric conditions at various altitudes.

Example Sentences

The logbooks were returned to naval authorities or ship owners, who used them to build pilot charts and guide later navigators.

From Reuters

Mapping had progressed steadily from the thirteenth century, when Italian merchant-venturers had developed the earliest portolan pilot charts of the Mediterranean, using compass directions and observations to locate harbours.

From Nature