What is lines of latitude

what is lines of latitude

What Are the Five Major Lines of Latitude?

Nov 21,  · Lines or degrees of latitude are approximately 69 miles or km apart, with variation due to the fact that the earth is not a perfect sphere but an oblate ellipsoid (slightly egg-shaped). To remember latitude, imagine the lines as horizontal rungs of a ladder, "ladder-tude", or by the rhyme "latitude flat-itude". line of latitude - an imaginary line around the Earth parallel to the equator parallel of latitude, parallel, latitude polar circle - a line of latitude at the north or south poles horse latitude - either of two belts or regions near 30 degrees north or 30 degrees south; .

Latitude is a measurement on a globe or map of location north or south of the Equator. Technically, there are different kinds of latitude— geocentric, astronomical, and geographic or geodetic —but there are only minor differences between them. In most common references, geocentric latitude is implied. As aids to indicate different latitudinal positions on maps or globes, equidistant circles are plotted and drawn parallel to the Equator and each other; they are known as parallelsor parallels of latitude.

In contrast, what is lines of latitude latitude, which is the kind used in mapping, is calculated using a slightly different process.

Different methods are used to determine geographic how hard is it to change an o2 sensor, as by taking angle-sights on certain polar stars or by measuring with a sextant the angle of the noon Sun above the horizon.

Geographic latitude is also given in degrees, minutes, and seconds. Longitude is a measurement of location east or west of the prime meridian at Greenwichthe specially designated imaginary north-south line that passes through both geographic poles and Greenwich, London.

As aids to locate longitudinal positions on a globe or map, meridians are plotted and drawn from pole to pole where they wht. The distance per degree of oc at the Equator is about Latitude and longitude. Videos Images. Additional Info. More About Contributors Article How to print screen on galaxy tab. Print Cite verified Cite.

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External Websites. National Geographic - Latitude. Articles from Britannica Encyclopedias for elementary and high school students. The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree See Article History.

Perspective of the globe with grid formed by parallels of latitude and meridians ls longitude. Britannica Quiz. Even More Geography Fun Facts. Take this quiz and join Britannica on another fun journey! Overview explaining the coordinate system of latitude and longitude, which is used to describe the location of any place on Earth's surface. This cutaway drawing shows that the latitude and longitude of lafitude place are based on the sizes of two angles that originate at the centre of Earth.

Geocentric latitude and geographic latitude. Get a Britannica Premium subscription and gain access to exclusive content. Subscribe Now. As shown on the small-scale globe perspective, Washington, D. Learn More in these related Britannica articles:. Portuguese seamen determined latitude what channel is fx on fios tv observing the elevation angle of the polestar—that is, the angle between its direction and the horizontal.

The noontime elevation angle reaches a maximum at all latitudes north of the Tropic of Cancer South of the Tropic of Capricorn Two or more maps can be overlaid and integrated for analysis—such as a relief map and a map of wells—even if they are compiled on different….

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The Arctic Circle

Distance north or south on the Earth's surface, measured in degrees from the equator, which has a latitude of 0°. The distance of a degree of latitude is about 69 statute miles ( kilometers) or 60 nautical miles. Latitude and longitude are the coordinates used . Nov 06,  · Latitude is the measurement of distance north or south of the Equator. It is measured with imaginary lines that form circles around the Earth east-west, parallel to the Equator. These lines are known as parallel s. A circle of latitude is an imaginary ring linking all points sharing a parallel. The lines of latitude are horizontal, as opposed to the lines of longitude, which are vertical. The lines of Longitude and Latitude are two set of imaginary lines that envelop the Earth. The earth has a vast area of surface. Due to this it is often hard to locate something exactly on the planet.

In geography , latitude is a geographic coordinate that specifies the north — south position of a point on the Earth's surface. Lines of constant latitude, or parallels , run east—west as circles parallel to the equator.

Latitude is used together with longitude to specify the precise location of features on the surface of the Earth. On its own, the term latitude should be taken to be the geodetic latitude as defined below. Briefly, geodetic latitude at a point is the angle formed by the vector perpendicular or normal to the ellipsoidal surface from that point, and the equatorial plane.

Also defined are six auxiliary latitudes that are used in special applications. Two levels of abstraction are employed in the definition of latitude and longitude. In the first step the physical surface is modeled by the geoid , a surface which approximates the mean sea level over the oceans and its continuation under the land masses.

The second step is to approximate the geoid by a mathematically simpler reference surface. The simplest choice for the reference surface is a sphere , but the geoid is more accurately modeled by an ellipsoid. The definitions of latitude and longitude on such reference surfaces are detailed in the following sections. Lines of constant latitude and longitude together constitute a graticule on the reference surface. The latitude of a point on the actual surface is that of the corresponding point on the reference surface, the correspondence being along the normal to the reference surface which passes through the point on the physical surface.

Latitude and longitude together with some specification of height constitute a geographic coordinate system as defined in the specification of the ISO standard. Since there are many different reference ellipsoids , the precise latitude of a feature on the surface is not unique: this is stressed in the ISO standard which states that "without the full specification of the coordinate reference system, coordinates that is latitude and longitude are ambiguous at best and meaningless at worst".

This is of great importance in accurate applications, such as a Global Positioning System GPS , but in common usage, where high accuracy is not required, the reference ellipsoid is not usually stated. It is measured in degrees , minutes and seconds or decimal degrees , north or south of the equator. For navigational purposes positions are given in degrees and decimal minutes. The precise measurement of latitude requires an understanding of the gravitational field of the Earth, either to set up theodolites or to determine GPS satellite orbits.

The study of the figure of the Earth together with its gravitational field is the science of geodesy. This article relates to coordinate systems for the Earth: it may be extended to cover the Moon, planets and other celestial objects by a simple change of nomenclature. The graticule is formed by the lines of constant latitude and constant longitude, which are constructed with reference to the rotation axis of the Earth. The primary reference points are the poles where the axis of rotation of the Earth intersects the reference surface.

Planes which contain the rotation axis intersect the surface at the meridians ; and the angle between any one meridian plane and that through Greenwich the Prime Meridian defines the longitude: meridians are lines of constant longitude.

The plane through the centre of the Earth and perpendicular to the rotation axis intersects the surface at a great circle called the Equator. Planes parallel to the equatorial plane intersect the surface in circles of constant latitude; these are the parallels. The latitude of an arbitrary point is the angle between the equatorial plane and the normal to the surface at that point: the normal to the surface of the sphere is along the radius vector.

The latitude, as defined in this way for the sphere, is often termed the spherical latitude, to avoid ambiguity with the geodetic latitude and the auxiliary latitudes defined in subsequent sections of this article. The plane of the Earth's orbit about the Sun is called the ecliptic , and the plane perpendicular to the rotation axis of the Earth is the equatorial plane. The angle between the ecliptic and the equatorial plane is called variously the axial tilt, the obliquity, or the inclination of the ecliptic, and it is conventionally denoted by i.

The axis of rotation varies slowly over time and the values given here are those for the current epoch. The time variation is discussed more fully in the article on axial tilt.

The figure shows the geometry of a cross-section of the plane perpendicular to the ecliptic and through the centres of the Earth and the Sun at the December solstice when the Sun is overhead at some point of the Tropic of Capricorn. The south polar latitudes below the Antarctic Circle are in daylight, whilst the north polar latitudes above the Arctic Circle are in night. The situation is reversed at the June solstice, when the Sun is overhead at the Tropic of Cancer.

Only at latitudes in between the two tropics is it possible for the Sun to be directly overhead at the zenith. On map projections there is no universal rule as to how meridians and parallels should appear. The examples below show the named parallels as red lines on the commonly used Mercator projection and the Transverse Mercator projection. On the former the parallels are horizontal and the meridians are vertical, whereas on the latter there is no exact relationship of parallels and meridians with horizontal and vertical: both are complicated curves.

R is equal to 6, km or 3, miles. No higher accuracy is appropriate for R since higher-precision results necessitate an ellipsoid model. With this value for R the meridian length of 1 degree of latitude on the sphere is The length of 1 minute of latitude is 1. Newton's result was confirmed by geodetic measurements in the 18th century.

See Meridian arc. An oblate ellipsoid is the three-dimensional surface generated by the rotation of an ellipse about its shorter axis minor axis. Ellipsoids which do not have an axis of symmetry are termed triaxial.

Many different reference ellipsoids have been used in the history of geodesy. In pre-satellite days they were devised to give a good fit to the geoid over the limited area of a survey but, with the advent of GPS , it has become natural to use reference ellipsoids such as WGS84 with centre at the centre of mass of the Earth and minor axis aligned to the rotation axis of the Earth.

These geocentric ellipsoids are usually within m ft of the geoid. Since latitude is defined with respect to an ellipsoid, the position of a given point is different on each ellipsoid: one cannot exactly specify the latitude and longitude of a geographical feature without specifying the ellipsoid used.

Many maps maintained by national agencies are based on older ellipsoids, so one must know how the latitude and longitude values are transformed from one ellipsoid to another. GPS handsets include software to carry out datum transformations which link WGS84 to the local reference ellipsoid with its associated grid.

The shape of an ellipsoid of revolution is determined by the shape of the ellipse which is rotated about its minor shorter axis. Two parameters are required. One is invariably the equatorial radius, which is the semi-major axis , a. The other parameter is usually 1 the polar radius or semi-minor axis , b ; or 2 the first flattening , f ; or 3 the eccentricity , e.

These parameters are not independent: they are related by. Many other parameters see ellipse , ellipsoid appear in the study of geodesy, geophysics and map projections but they can all be expressed in terms of one or two members of the set a , b , f and e. Values for a number of ellipsoids are given in Figure of the Earth. The difference between the semi-major and semi-minor axes is about 21 km 13 miles and as fraction of the semi-major axis it equals the flattening; on a computer monitor the ellipsoid could be sized as by pixels.

This would barely be distinguishable from a bypixel sphere, so illustrations usually exaggerate the flattening. The graticule on the ellipsoid is constructed in exactly the same way as on the sphere. The normal at a point on the surface of an ellipsoid does not pass through the centre, except for points on the equator or at the poles, but the definition of latitude remains unchanged as the angle between the normal and the equatorial plane.

The terminology for latitude must be made more precise by distinguishing:. The importance of specifying the reference datum may be illustrated by a simple example.

The same coordinates on the datum ED50 define a point on the ground which is metres feet distant from the tower. For WGS84 this distance is 10 The evaluation of the meridian distance integral is central to many studies in geodesy and map projection. It can be evaluated by expanding the integral by the binomial series and integrating term by term: see Meridian arc for details. The length of the meridian arc between two given latitudes is given by replacing the limits of the integral by the latitudes concerned.

The length of a small meridian arc is given by [5] [6]. The distance in metres correct to 0. The variation of this distance with latitude on WGS84 is shown in the table along with the length of a degree of longitude east—west distance :. A calculator for any latitude is provided by the U. The following graph illustrates the variation of both a degree of latitude and a degree of longitude with latitude. Historically a nautical mile was defined as the length of one minute of arc along a meridian of a spherical earth.

An ellipsoid model leads to a variation of the nautical mile with latitude. This was resolved by defining the nautical mile to be exactly 1, metres. However, for all practical purposes distances are measured from the latitude scale of charts. There are six auxiliary latitudes that have applications to special problems in geodesy, geophysics and the theory of map projections:.

The definitions given in this section all relate to locations on the reference ellipsoid but the first two auxiliary latitudes, like the geodetic latitude, can be extended to define a three-dimensional geographic coordinate system as discussed below.

The remaining latitudes are not used in this way; they are used only as intermediate constructs in map projections of the reference ellipsoid to the plane or in calculations of geodesics on the ellipsoid. Their numerical values are not of interest.

For example, no one would need to calculate the authalic latitude of the Eiffel Tower. The expressions below give the auxiliary latitudes in terms of the geodetic latitude, the semi-major axis, a , and the eccentricity, e. For inverses see below. The forms given are, apart from notational variants, those in the standard reference for map projections, namely "Map projections: a working manual" by J. The geocentric latitude is the angle between the equatorial plane and the radius from the centre to a point on the surface.

The geodetic and geocentric latitudes are equal at the equator and at the poles but at other latitudes they differ by a few minutes of arc. Taking the value of the squared eccentricity as 0. It was introduced by Legendre [11] and Bessel [12] who solved problems for geodesics on the ellipsoid by transforming them to an equivalent problem for spherical geodesics by using this smaller latitude.

The parametric latitude is related to the geodetic latitude by: [5] [6]. The alternative name arises from the parameterization of the equation of the ellipse describing a meridian section. In terms of Cartesian coordinates p , the distance from the minor axis, and z , the distance above the equatorial plane, the equation of the ellipse is:. Cayley suggested the term parametric latitude because of the form of these equations. The parametric latitude is not used in the theory of map projections.

Its most important application is in the theory of ellipsoid geodesics, Vincenty , Karney [14]. The sphere may then be projected to the plane with an equirectangular projection to give a double projection from the ellipsoid to the plane such that all meridians have true length and uniform meridian scale.

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