Pilot charts are certainly of great help for planning ocean routes and fortunately, the U.S. Defense Mapping Agency makes their Atlas of Pilot Charts available for free (get it here. you may find their server somewhat slow and rather try it here).
I’ve recently generated kml/kmz files that show the prevailing ocean winds (get more info here). Viewing them with Google Maps (as in our map at Pitufa.at) or Google Earth is really convenient. So I decided to put more information from pilot charts in kml/kmz files. For a start the gale probabilities are done.
Download Gale Probability KMZ File
Download this kmz file to get an interactive atlas of world-wide ocean storm probabilities. You may simply load it into your Google Earth (File > Open…). In your ‘My Places’ panel you will get a list to switch between the months. The red numerals in 5-by-5 degree areas show the average percentage of ship reports in which winds of at least force 8 have been recorded for the considered month. However, be aware of the notes found in the original pilot charts and that we cannot guarantee the data to be free of errors. Read the disclaimer found in the files.
Sources:
U.S. Defense Mapping Agency: Pub. 105, Atlas of Pilot Charts South Atlantic Ocean, Ed. 1995; Pub. 106, Atlas of Pilot Charts North Atlantic Ocean, Ed. 2002; Pub. 107, Atlas of Pilot Charts South Pacific Ocean, Ed. 1998; Pub. 108, Atlas of Pilot Charts North Pacific Ocean, Ed. 1994; Pub. 109, Atlas of Pilot Charts Indian Ocean, Ed. 2001
