Lines on a Map
Basically, a map is a graphic representation of the real world on a flat surface. The infinite nature of our universe makes it nearly impossible to capture all of the complexities found in the real world. The study of construction of a map is called cartography.
There are various points and lines present on a map which not only define where we are, but also the real time when we are there. We can’t see them, but they exist. Navigators still depend on these imaginary lines to know where they are going.
An equator is an imaginary circle that goes round the middle of the earth for 24,902 miles. It is exactly half way between the North and South Poles and divides the Northern Hemisphere from the Southern Hemisphere.
The earth is imaginarily divided into two halves, known as hemispheres by the equator. The Northern Hemisphere is the northern half of the earth that lies between the North Pole and the equator. The Southern Hemisphere is the southern half of the earth that lies between the South Pole and the equator. Apart from these two, the earth can also be divided into Eastern Hemisphere and the Western Hemisphere. The Eastern Hemisphere consists of Asia, Africa, Australia, and Europe. The Western Hemisphere consists of North and South America, their islands, and the surrounding waters.
The Arctic Circle
The Arctic Circle lies at approximately 66.5 degrees north of the equator. Arctic region lies above this region which has 24 hours of nights in the middle of winter. It is also known as the Land of the Midnight Sun because in summer the sun never sets.
The Dew line or distant early warning line is a 3,000-mile line of radar stations north of the Arctic Circle to give early warning of aircraft or missile attack on North America.
The Antarctic Circle
The Antarctic Circle lies at approximately 66.5 degrees south of the equator. Antarctic region lies below this region. On the day of the southern summer solstice, i.e. around December 22 every year, an observer sees the Sun above the horizon for a full 24 hours.
These are the imaginary lines running east and west on a map. Parallels represent degrees of latitude, or how far a place is away from the equator. The equator lies at 0° latitude and the poles are at 90° of south and north. One degree of latitude equals about 69 miles.
These are the imaginary lines that run north and south on a map from pole to pole. Meridians express degrees of longitude, or how far a place is away from the prime meridian. The prime meridian runs through Greenwich, England. Longitudes and latitudes together, form a grid on which it is possible to locate any place on the earth. It is the meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle.
The International Date Line
The International Date Line is an imaginary line located halfway around the world from the prime meridian (0° longitude) or about 180° east or west of Greenwich (the reference point of time zones). It is also known as the line of demarcation. It is the line where the date changes one day when passed. It is one day earlier east of the line than it is on the west.
The Tropic of Cancer
It is an imaginary parallel latitude that lies at approximately 23.5 degrees north of the equator. It is the northernmost point on Earth where the sun’s rays appear directly overhead at local noon during summer solstice.
The Tropic of Capricorn
Also Read | Basic concepts of Geography