Geographic Coordinates: Latitude, Longitude, Equator, Tropic of Cancer, Capricorn, Hemispheres, Torrid, Temperate zone

Geographic Coordinates system : Geographic coordinate system is a coordinate system that enables every location on the Earth to be specified by a set of numbers or letters. The coordinates are often chosen such that one of the numbers represents vertical position, and two or three of the numbers represent horizontal position. A common choice of coordinates is latitude, longitude and elevation.

Geography of World and India

Latitude indicates the location of a place on Earth north or south of the Equator. Latitude is an angular measurement in degrees (marked with °) ranging from 0° at the Equator to 90° at the poles (90° N for the North Pole or 90° S for the South Pole).
Longitude is an imaginary line that runs from the North Pole to the South Pole and is used to describe the location of a place on Earth east or west of the zero or prime meridian. In 1884, the International Meridian Conference adopted the Greenwich Meridian as the universal prime meridian or zero point of longitude. Longitude is measured in degrees ranging from 0° at the Prime Meridian to +180° eastward and -180° westward. Each degree of longitude is further sub-divided into 60 minutes, each of which is further sub-divided into 60 seconds.
Equator: Located at zero degrees latitude (North or South,) is 24,901.55 miles long and divides the Planet Earth into the Northern and Southern Hemispheres. 
Tropics of Cancer and Capricorn: Located at 23.5 degrees North and 23.5 degrees South of the Equator, this area of Planet Earth (between those two lines) is known as the "Tropics," and is colored with a lighter blue color on the globe. This area experiences no dramatic change in season because the sun is consistently high in the sky throughout the year.
Arctic Circle: It is one of the five major circles of latitude that mark maps of the Earth. Its exact location varies slightly each year, and currently it's positioned at 66° 33′ 44″ (or 66.5622°) north of the Equator.
dot
Antarctic Circle: This parallel of latitude is currently at 66° 33′ 44″ ( or 66.5622°) south of the Equator.
Prime Meridian: Located at zero degrees longitude (East or West), it divides the Planet Earth into the Eastern and Western Hemispheres, and is the line from which all other lines of longitude are measured. Prime meridian passes through Greenwich near london, where the British Royal Observatory is located. Its value is O Degree.
International Date Line (IDL): International Date Line (IDL), is an imaginary line on the surface of the Earth that runs from the north to the south pole and demarcates one calendar day from the next. It passes through the middle of the Pacific Ocean, roughly following the 180° longitude but it deviates to pass around some territories and island groups.
IMPORTANT TERM TO REMEMBER:
* Equator: 0° Longitude
* Tropic of Cancer: 23.5° North
* Tropic of Capricorn: 23.5° Sourth
* Torrid Zone: Area between tropic of Cancer and Capricorn which receive maximum head.
* Temperate Zone: Area between Tropic of Cancer and Arctic Circle and Tropic of Capricorn and Antarctic Circle, which receive moderate temperature.
* Prime meridian: It passes through Greenwich near London, where the British Royal Observatory is located. Its value is 0°.
* Equinox: 21st March & 21st September 2013
* Summer Solstice: 21st June
* Winter Solstice: 22nd December
* Nearest start to earth: 1. Sun, 2. Proxima Centuari.