Using Landmarks at Sea

Without the availability of Radars, GPS (Global Positioning Systems) and electronic depth gauges, boaters, surfers and fishermen who move around coastal areas do have the use of landmarks to help triangulate their position and course when traveling on or near the water. Depending upon the terrain and circumstance, they rely upon mountains, rocks, tall trees, buildings and other such objects like lighthouses and even Ahu and Moai to provide a direct line of sight. Not only can they be used to guide ships towards shore but away, as well.