The selection of the most favorable route for a ship's transit in the open ocean. Safety, economics, and environmental protection play a key role in determining this selection. In the late 1890s, the practice of following predetermined routes for shipping was adopted by shipping companies operating in the North Atlantic. As ships grew both in size and number, the ability to plan open-ocean transits based upon the environmental conditions expected during a voyage and the effect of these conditions upon the ship's performance became important factors in planning a ship's route. Ship routing is also referred to as weather routing, optimum track ship routing, and meteorological navigation.