Without charts, the only means to determine a sailor’s or explorer’s location was celestial navigation. As noted in a previous column, the captain’s chart was little more than the ship’s log. On old maps, a circular directional emblem is a “wind rose.” Mariners in Homer’s time identified direction with wind and early cartographers were part-artist, part-astronomer, combining wind direction into the wind rose. Once nautical charts were initiated in the 14th century, the four primary winds were schematically positioned around a circle that represented the horizon. Always present was the wind rose that contained a radial set of points, such as a star, directed into each wind position. The rhumb lines radiated from the central point of the rose, connected to each directional point. More on Monday. Fastcast: Getting warmer.

Sunny, with a high near 89 degrees. Calm wind becoming southerly between 5 and 10 mph. Tonight, mostly clear, with a low about 70 degrees. Southerly wind between 5 and 10 mph.