A number of modern technologies, including computer, satellite navigation, and in some cases radar, are combined to create electronic charts. These charts display where a conveyance (marine, aerospace, or land vehicle) is located, as well as where it has been and where it is headed. Information is also provided to guide the conveyance to its destination while avoiding hazards that lie along the route. In these systems, a nautical chart or a land map is displayed on a computer's screen or on a hand-held device, showing appropriate detail. A symbol that marks the vehicle's present location and a track of its previous positions is drawn on the chart or map. In the case of marine vessels, radar images of objects in the water show the location of shore, lights, and buoys, as well as the presence and tracks of other ships in the area. Thus, the electronic chart shows a complete picture of the situation facing a pilot or driver.