Latitude and
Longitude
Latitude runs the
distance from the equator to the North or South
Pole.The lines of latitude illustrate the
imaginary horizontal lines shown on
a map extending east
to west or west to east. Latitude indicates the
location of a place on Earth or other planetary
bodies. Latitude corresponds to
an angular measurement in degrees marked by
the symbol, degree °. Latitude starts from
0° at the equator to 90° at the North
and South Pole. It is written 90° S
or -90° to denote the
South Pole or 90° N or +90° representing the
North Pole. All latitude lines are parallel
to the equator. Lines of latitude correspond to
small circles around the Earth's surface. Latitude
lines appear horizontal.
The equator has a
latitude of 0° and divides the
Earth into the Northern Hemisphere and the Southern
Hemisphere.
Longitude represents a
measure of the distance east to west from the reference
line called the
prime meridian. The prime meridian stretches from
the North Pole to the South Pole and passes through
Greenwich, England. The term longitude was chosen because
the lines are all
the same length and longer than any line of latitude.
Even the equator is shorter
because Earth is not
a perfect sphere. Earth bulges in
the middle, giving it
a rounded pear-shape. Lines of longitude appear vertical.
The line of longitude that passes through
the Royal Observatory, Greenwich, England establishes the
meaning of zero degrees of longitude or the prime
meridian. There is no
natural starting position for longitude unlike
latitude, the equator; therefore, a reference meridian
had to be chosen.
In 1884 the International Meridian Conference adopted the
Greenwich meridian as the universal prime meridian
or zero point of longitude. Longitude is given as
an angular measurement ranging from
0° at the prime meridian to +180° eastward
and −180° westward.
A specific latitude may be combined with
a specific longitude to provide a
precise position on the Earth's surface.
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