• chart
    Submariners use a chart to navigate underwater.

    Photograph by J. Baylor Roberts

    Chart Error
    Nautical charts that Christopher Columbus used when he set off from Spain showed nothing but ocean between him and eastern China. That's why his discovery of the Americas was such a lucky, lucky surprise.

    Charts help captains of ships and pilots of airplanes navigate to their destination quickly and safely. They are like maps, but for the sea and air. There are two kinds of charts: nautical charts and aeronautical charts.

    Nautical charts feature information about the sea, such as depth and behavior of the water in particular areas. Nautical charts detail where swells, tides, and ocean gyres develop. Nautical charts also represent features of the sea floor, such as canyons and reefs. They may contain the locations of man-made features such as buoys, lighthouses, and harbors. Sea captains use this information to plan their routes. They also use the charts to determine the location of their ship.

    Aeronautical charts show features of the land such as mountain ranges, bodies of water, tall buildings, airports, and safe landing areas for pilots. They also show the distance between certain points and the official airspace of different countries. Aeronautical charts typically display different radio frequencies for the areas they depict, so pilots can call for assistance in an emergency or bad weather. These charts help pilots navigate their airplanes and determine a safe flying altitude.

    Both types of charts include information about the Earths magnetic field. This is important because equipment can experience irregularities as vessels approach the magnetic north pole or the magnetic south pole.

    Most charts are printed on large sheets of paper and come in different scales. Some charts depict a very small area, such as the coastline around a harbor. Others depict an entire ocean or continent. There are also electronic charts, created using a geographic information system (GIS). GIS charts are stored on computers.

  • Term Part of Speech Definition Encyclopedic Entry
    aeronautical chart Noun

    map designed to help navigate aircraft.

    airspace Noun

    region of the Earth's atmosphere controlled by a particular nation or country.

    altitude Noun

    the distance above sea level.

    Encyclopedic Entry: altitude
    buoy Noun

    floating object anchored to the bottom of a body of water. Buoys are often equipped with signals.

    canyon Noun

    deep, narrow valley with steep sides.

    Encyclopedic Entry: canyon
    chart Noun

    type of map with information useful to ocean or air navigators.

    Encyclopedic Entry: chart
    continent Noun

    one of the seven main land masses on Earth.

    Encyclopedic Entry: continent
    geographic information system (GIS) Noun

    any system for capturing, storing, checking, and displaying data related to positions on the Earth's surface.

    Encyclopedic Entry: GIS (geographic information system)
    harbor Noun

    part of a body of water deep enough for ships to dock.

    Encyclopedic Entry: harbor
    irregularity Noun

    an unusual behavior or occurrence.

    lighthouse Noun

    structure displaying large, bright lights to warn and help ships navigate coastal waters.

    magnetic field Noun

    area around and affected by a magnet or charged particle.

    mountain range Noun

    series or chain of mountains that are close together.

    nautical chart Noun

    representation of spatial information displaying data on bodies of water and coastal areas.

    navigate Verb

    to plan and direct the course of a journey.

    north magnetic pole Noun

    constantly moving area where compass needles point from all over the Earth.

    ocean Noun

    large body of salt water that covers most of the Earth.

    Encyclopedic Entry: ocean
    ocean gyre Noun

    an area of ocean that slowly rotates in an enormous circle.

    Encyclopedic Entry: ocean gyre
    radio frequency Noun

    range of electromagnetic waves over which certain information, such as sound, can be communicated.

    reef Noun

    a ridge of rocks, coral, or sand rising from the ocean floor all the way to or near the ocean's surface.

    route Noun

    path or way.

    south magnetic pole Noun

    constantly moving area where south compass needles point from all over the Earth.

    swell Noun

    stable, crestless wind wave formed far out at sea.

    tide Noun

    rise and fall of the ocean's waters, caused by the gravitational pull of the moon and sun.

    Encyclopedic Entry: tide

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