Latitude and Longitude
Basis of Geographic Coordinate and Navigation System
Latitude lines are the imaginary circled lines that runs across the planet in east - west direction. Latitudes circles are called circles of Latitude and Parallels, as they are parallel to the Equator.
Latitude values to the North of the equator are specified by 0° to 90° N.
Latitude values to the South of the equator are specified by 0° to 90° S.
Major latitude circles
Equator is the parallel or the a latitude line that notionally run across the planet in east - west direction from exact between, at 0° latitude, equidistant from both the poles and hence dividing Earth into two halves - Northern Hemisphere and Southern Hemisphere. Equator is the longest of all the parallels.
Locations pointed out above the equator have value between 0° (the equator) and 90° N (the North Pole), while locations pointed out below the equator have value between 0° (the equator) and 90° S (the South Pole).
Tropic of Cancer
Tropic of Cancer, also known as Northern Tropic, is the latitude line that run across the planet at 23.4° N latitude (or 23.4° north to equator). It the most north-ly latitude at which Sun can directly overhead on Earth.
Tropic of Capricorn
Tropic of Capricorn, also known as Southern Tropic, is the latitude line that run across the planet at 23.4° S latitude (or 23.4° south to equator). It the most south-ly latitude at which Sun can directly overhead on Earth.
Arctic circle is a parallel at 66.5° N to the equator. It is one of the two polar circles of the planet in northern hemisphere.
Antarctic circle is a parallel at 66.5° S to the equator. It is second of the two polar circles of the planet in the southern hemisphere.
Longitude lines are the imaginary circled lines that runs across the planet in north - south direction. Longitudes lines are called Meridians. Longitude measure how far east or west a point on Earth lies from the prime meridian. All the meridians have terminal points - North pole and South pole. All the meridians are equal in length to each other.
Longitude values to the east of the prime meridian can be specified by 0° to 180° E.
Longitude values to the west of the prime meridian can be specified by 0° to 180° W.
Prime Meridian, a contrast line to Equator but in vertical direction, is a great circle that divides the Earth into two equal halves vertically - Western Hemisphere and Eastern Hemisphere. Prime meridian is also at 0°, just like equator, but runs vertically.
Why this imaginary system of circles?
Together Latitude and Longitude form the navigation and coordination system, that helps us locate, pin-point or trace-out any location or place on the Earth’s surface.
Latitudes and Longitudes are the basis of cartography (study and practise of map making)
Latitudes and Longitudes helps in determining horizontal and vertical extent of a graphical entity. Example: Countries.
Latitude in particular help in understanding various geographical concepts. including distribution of isolation on Earth surface, rainfall distribution etc.
What is at 0° Latitude and 0° longitude?
The equator is the zero degrees latitude while the prime meridian is the zero degrees longitude. To be precise, the place where the equator and prime meridian meet falls. This place is in the eastern Atlantic Ocean. More specifically, it is in the Gulf of Guinea named as Null island (also jokingly called Zero Zero Island). Though, this place is named an 'island', but there is not apparent 'land' at this intersection point of equator and prime meridian. This names just serves as the label for the suppositional existence of an Island. There is no geographical, physical or any political significance of this point.
Vocab - Latitude and Longitude
Polar night occurs in the northernmost and southernmost regions of the Earth, precisely inside the polar circles, when the night lasts for more than 24 hours.
Polar Day / Midnight Sun
Polar day, a contrast phenomenon to polar night, the occurs when the Sun stays above the free horizon for more than 24 hours for regions inside polar circles.