Many are or derive from nautical terms and other naval terminology. A naval ship's navigator is responsible for buying and maintaining its nautical charts. Isogonic lines are also shown on aeronautical and nautical charts. Garmin offers different maps for purchase, including detailed road maps, topographic maps and nautical maps. To the 12 nautical miles boundary is Australia's territorial waters. Adams' knowledge of ships, shipbuilding and nautical smattering of mathematics appealed to Ieyasu. These aerodynamic improvements result in an increase in range of over 300 nautical miles. Thus became the metric length for a nautical mile. Many land time zones are skewed toward the west of the corresponding nautical time zones. An ellipsoid model leads to a variation of the nautical mile with latitude. His career inspired a number of writers of nautical fiction. Western books were prohibited, with the exemption of books on nautical and medical matters. The length of the internationally agreed nautical mile is . One is that the terms derive from early nautical navigation. Each stage of twilight (civil, nautical, and astronomical) lasts only 24 minutes.