A navigation chart is a specialized map or graphic representation that provides essential information for safe and efficient navigation of ships, aircraft, or other vehicles in water or air. It offers comprehensive visual and textual data to aid navigators in determining their position, planning routes, and avoiding hazards.
These charts typically include navigational aids such as lighthouses, buoys, beacons, and radio towers, enabling mariners to accurately locate their vessel. They also depict topographic features such as coastline outlines, shoreline characteristics, depth contours, and underwater features like coral reefs or shoals. Additionally, a navigation chart provides information about water depths, tidal variations, currents, and magnetic variations, crucial for maintaining proper course and avoiding potential dangers.
Navigation charts can vary in scale, depending on the specific requirements of the navigational area they cover. Large-scale charts offer more detailed information for relatively confined areas such as ports or harbors, while small-scale charts provide a broader overview for open ocean navigation. These charts are continuously updated to reflect changes in coastal features, water depths, and other navigational elements.
In summary, a navigation chart is an essential tool used by navigators to determine their position, plan routes, and navigate safely and efficiently. It combines precise geographical information, details of navigational aids, and other critical data to ensure the success of marine or aerial navigational efforts.
The etymology of the word "navigation" can be traced back to the Latin word "navigatio", which comes from the verb "navigare", meaning "to sail" or "to navigate". It is derived from the combination of the words "navis" (meaning "ship") and "agere" (meaning "to drive" or "to direct").
The word "chart", on the other hand, originates from the Latin word "charta", which was borrowed from the Greek word "khartēs" meaning "papyrus". In English, "chart" refers to a detailed map or diagram used for navigation, specifically at sea. The term "chart" has been used since the 16th century to describe navigational maps and diagrams.
Therefore, when combined, the term "navigation chart" refers to a map or diagram that provides information for sailing or navigating a ship at sea.