User Contributed Dictionary
Noun
latitudes Plural of latitude
Anagrams
Extensive Definition
Latitude, usually denoted symbolically by the
Greek letter phi,
\phi\,\!, gives the location of a place on Earth (or other
planetary body) north or south of the equator. Lines of Latitude are
the horizontal lines shown running easttowest on maps.
Technically, latitude is an angular measurement in degrees
(marked with °) ranging from 0° at the equator (low latitude) to
90° at the poles (90° N for the North Pole or
90° S for the South Pole;
high latitude). The complementary
angle of a latitude is called the colatitude.
Circles of latitude
All locations of a given latitude are collectively referred to as a circle of latitude or line of latitude or parallel, because they are coplanar, and all such planes are parallel to the equator. Lines of latitude other than the Equator are approximately small circles on the surface of the Earth; they are not geodesics since the shortest route between two points at the same latitude involves a path that bulges toward the nearest pole, first moving farther away from and then back toward the equator (see great circle).A specific latitude may then be combined with a
specific longitude to
give a precise position on the Earth's surface (see
satellite navigation system).
Important named circles of latitude
Besides the equator, four other lines of latitude are named because of the role they play in the geometrical relationship with the Earth and the Sun: Arctic Circle — 66° 33′ 39″ N
 Tropic of Cancer — 23° 26′ 21″ N
 Tropic of Capricorn — 23° 26′ 21″ S
 Antarctic Circle — 66° 33′ 39″ S
Only at latitudes between the Tropics is it
possible for the sun to be
at the zenith. Only north
of the Arctic
Circle or south of the Antarctic
Circle is the midnight sun
possible.
The reason that these lines have the values that
they do, lies in the axial tilt of
the Earth with respect to the sun, which is 23° 26′
21.41″.
Note that the Arctic Circle and Tropic of Cancer
and the Antarctic Circle and Tropic of Capricorn are colatitudes
since the sum of their angles is 90°.
Subdivisions
To simplify calculations where elliptical consideration is not important, the nautical mile was created, equaling exactly 111.12 km per degree of arc or, subdividing into minutes, 1852 metres per minute of arc. One minute of latitude can be further divided into 60 seconds. A latitude is thus specified as 13°19'43″ N (for greater precision, a decimal fraction can be added to the seconds). An alternative representation uses only degrees and minutes, where the seconds are expressed as a decimal fraction of minutes, thus the above example is expressed as 13°19.717' N. Degrees can also be expressed singularly, with both the minutes and seconds incorporated as a decimal number and rounded as desired (decimal degree notation): 13.32861° N. Sometimes, the north/south suffix is replaced by a negative sign for south (−90° for the South Pole).Effect of latitude
A region's latitude has a great effect on its
climate and weather (see
Effect of sun angle on climate). Latitude more loosely
determines tendencies in polar
auroras, prevailing
winds, and other physical characteristics of geographic
locations.
Researchers at Harvard's Center
for International Development (CID) found in 2001 that only three
tropical economies —
Hong
Kong, Singapore, and
Taiwan —
were classified as highincome by the World Bank,
while all countries within regions zoned as temperate had either middle
or highincome economies.
Elliptic parameters
Because most planets (including Earth) are ellipsoids of revolution, or spheroids, rather than spheres, both the radius and the length of arc varies with latitude. This variation requires the introduction of elliptic parameters based on an ellipse's angular eccentricity, o\!\varepsilon\,\! (which equals \scriptstyle\,\!, where a\;\! and b\;\! are the equatorial and polar radii; \scriptstyle\;\! is the first eccentricity squared, \;\!; and \scriptstyle\;\! or \scriptstyle\;\! is the flattening, \;\!). Utilized in creating the integrands for curvature is the inverse of the principal elliptic integrand, E'\;\!:n'(\phi)=\frac =\frac;\,\!

 \begin
Degree length
The length of an arcdegree of latitude (northsouth) is about 60 nautical miles, 111 kilometres or 69 statute miles at any latitude. The length of an arcdegree of longitude (eastwest) at the equator is about the same, reducing to zero at the poles.In the case of a spheroid, a meridian
and its antimeridian form an ellipse, from which an exact
expression for the length of an arcdegree of latitude is:

 \fracM(\phi)\;\!
Along the equator (eastwest), N\;\! equals the
equatorial radius. The radius of curvature at a right angle
to the equator (northsouth), M\;\!, is 43 km shorter, hence the
length of an arcdegree of latitude at the equator is about 1 km
less than the length of an arcdegree of longitude at the equator.
The radii of curvature are equal at the poles where they are about
64 km greater than the northsouth equatorial radius of curvature
because the polar radius is 21 km less than the equatorial radius.
The shorter polar radii indicate that the northern and southern
hemispheres are flatter, making their radii of curvature longer.
This flattening also 'pinches' the northsouth equatorial radius of
curvature, making it 43 km less than the equatorial radius. Both
radii of curvature are perpendicular to the plane tangent to the
surface of the ellipsoid at all latitudes, directed toward a point
on the polar axis in the opposite hemisphere (except at the equator
where both point toward Earth's center). The eastwest radius of
curvature reaches the axis, whereas the northsouth radius of
curvature is shorter at all latitudes except the poles.
The WGS84 ellipsoid, used
by all GPS
devices, uses an equatorial radius of 6378137.0 m and an inverse
flattening, (1/f), of 298.257223563, hence its polar radius is
6356752.3142 m and its first eccentricity squared is
0.00669437999014. The more recent but little used IERS 2003 ellipsoid
provides equatorial and polar radii of 6378136.6 and 6356751.9 m,
respectively, and an inverse flattening of 298.25642. Lengths of
degrees on the WGS84 and IERS 2003 ellipsoids are the same when
rounded to six significant
digits. An appropriate calculator for any latitude is provided
by the U.S. government's
National GeospatialIntelligence Agency (NGA).
Types of latitude
With a spheroid that is slightly flattened by its rotation, cartographers refer to a variety of auxiliary latitudes to precisely adapt spherical projections according to their purpose. For planets other than Earth, such as Mars, geographic and geocentric latitude are called "planetographic" and "planetocentric" latitude, respectively. Most maps of Mars since 2002 use planetocentric coordinates.Common "latitude"
 In common usage, "latitude" refers to geodetic or geographic latitude \phi\,\! and is the angle between the equatorial plane and a line that is normal to the reference spheroid, which approximates the shape of Earth to account for flattening of the poles and bulging of the equator.
Reduced latitude
 Reduced or parametric latitude, \beta\,\!, is the latitude of the same radius on the sphere with the same equator.

 \beta=\arctan\Big(\cos(o\!\varepsilon)\tan(\phi)\Big);\,\!
Authalic latitude
 Authalic latitude, \xi\,\!, gives an areapreserving transform to the sphere.

 \widehat(\phi)^2=\fracb^2\left(\sin(\phi)n'(\phi)^2+\frac\right);\,\!

 \begin\xi&=\arcsin\!\left(\frac\right),\\
Rectifying latitude
 Rectifying latitude, \mu\,\!, is the surface distance from the equator, scaled so the pole is 90°, but involves elliptic integration:


 \mu=\frac

Conformal latitude
 Conformal latitude, \chi\,\!, gives an anglepreserving (conformal) transform to the sphere.

 \chi=2\cdot\arctan\left(\sqrt^\;\right)\frac;\;\!
Geocentric latitude
 The geocentric latitude, \psi\,\!, is the angle between the equatorial plane and a line from the center of Earth.

 \psi=\arctan\Big(\cos(o\!\varepsilon)^2\tan(\phi)\Big).\;\!
Comparison of latitudes
The following plot shows the differences between the types of latitude. The data used is found in the table following the plot. Please note that the values in the table are in minutes, not degrees, and the plot reflects this as well. Also note that the conformal symbols are hidden behind the geocentric due to being very close in value.Astronomical latitude
A more obscure measure of latitude is the astronomical latitude, which is the angle between the equatorial plane and the normal to the geoid (ie a plumb line). It originated as the angle between horizon and pole star.Astronomical latitude is not to be confused with
declination, the
coordinate astronomers use to describe
the locations of stars north/south of the celestial
equator (see equatorial
coordinates), nor with ecliptic
latitude, the coordinate that astronomers use to describe the
locations of stars north/south of the ecliptic (see ecliptic
coordinates).
Palæolatitude
Continents move over time, due to continental
drift, taking whatever fossils and other features of interest
they may have with them. Particularly when discussing fossils, it's
often more useful to know where the fossil was when it was laid
down, than where it is when it was dug up: this is called the
palæolatitude of the fossil. The Palæolatitude can be constrained
by palæomagnetic
data. If tiny magnetisable grains are present when the rock is
being formed, these will align themselves with Earth's magnetic
field like compass needles. A magnetometer can deduce the
orientation of these grains by subjecting a sample to a magnetic
field, and the magnetic
declination of the grains can be used to infer the latitude of
deposition.
Corrections for latitude
When converting from geodetic ("common")
latitude, corrections must be made for altitude for systems which
do not measure the angle from the normal of
the spheroid. In the figure at right, point H (located on the
surface of the spheroid) and point H (located at some greater
elevation) have different geocentric latitudes (angles β
and γ respectively), even though they share the same
geodetic latitude (angle α). (Note that the flatness of
the spheroid and elevation of point H is significantly greater than
what is found on the Earth, exaggerating the errors commonly found
in such calculations.)
Further reading
 John P. Snyder Map Projections: a working manual excerpts
See also
Footnotes
External links
 Free GeoCoder
 GEONets Names Server, access to the National GeospatialIntelligence Agency's (NGA) database of foreign geographic feature names.
 Lookup Latitude and Longitude
 Resources for determining your latitude and longitude
 Convert decimal degrees into degrees, minutes, seconds  Info about decimal to sexagesimal conversion
 Convert decimal degrees into degrees, minutes, seconds
 Latitude and longitude converter – Convert latitude and longitude from degree, decimal form to degree, minutes, seconds form and vice versa. Also included a farthest point and a distance calculator.
 Worldwide Index  Tageo.com
– contains 2,700,000 coordinates of places including US
towns
 for each city it gives the satellite map location, country, province, coordinates (dd,dms), variant names and nearby places.
 Distance calculation based on latitude and longitude  JavaScript version
latitudes in Afrikaans: Breedtegraad
latitudes in Tosk Albanian: Geografische
Breite
latitudes in Arabic: دائرة عرض
latitudes in Bengali: অক্ষাংশ
latitudes in Min Nan: Hūitō͘
latitudes in Belarusian (Tarashkevitsa):
Шырата
latitudes in Bosnian: Geografska širina
latitudes in Breton: Led
latitudes in Bulgarian: Географска ширина
latitudes in Catalan: Latitud
latitudes in Czech: Zeměpisná šířka
latitudes in Welsh: Lledred
latitudes in German: Geographische Breite
latitudes in Estonian: Laiuskraad
latitudes in Modern Greek (1453): Γεωγραφικό
πλάτος
latitudes in Spanish: Latitud
latitudes in Esperanto: Latitudo
latitudes in Basque: Latitude
latitudes in Persian: عرض جغرافیایی
latitudes in French: Latitude
latitudes in Galician: Latitude
latitudes in Hindi: अक्षांश रेखाएं
latitudes in Croatian: Zemljopisna širina
latitudes in Ido: Latitudo
latitudes in Igbo: Latitude
latitudes in Indonesian: Garis lintang
latitudes in Italian: Latitudine
latitudes in Hebrew: קו רוחב
latitudes in Swahili (macrolanguage):
Latitudo
latitudes in Kurdish: Hêlîpan
latitudes in Latin: Latitudo geographica
latitudes in Luxembourgish: Breedegrad
latitudes in Lithuanian: Platuma
latitudes in Lingala: Monkɔlɔ́tɔ mwâ
libale
latitudes in Macedonian: Латитуда
latitudes in Malayalam: അക്ഷാംശം
latitudes in Dutch: Breedtegraad
latitudes in Dutch Low Saxon: Breedtegraod
latitudes in Japanese: 緯度
latitudes in Norwegian Nynorsk:
Breiddegrad
latitudes in Polish: Szerokość
geograficzna
latitudes in Portuguese: Latitude
latitudes in Romanian: Latitudine
latitudes in Quechua: Kimra siwi
latitudes in Russian: Широта
latitudes in Simple English: Latitude
latitudes in Slovak: Zemepisná šírka
latitudes in Slovenian: Zemljepisna širina
latitudes in Serbian: Географска ширина
latitudes in Sundanese: Garis Datar
latitudes in Finnish: Leveyspiiri
latitudes in Swedish: Latitud
latitudes in Telugu: రేఖాంశం
latitudes in Thai: ละติจูด
latitudes in Turkish: Enlem
latitudes in Ukrainian: Широта
latitudes in Venetian: Latitudine
latitudes in Vlaams: Brêedtegroad
latitudes in Wolof: Tuswugaar
latitudes in Chinese: 纬度