Latitude — Safekipedia Adventurer

Latitude is a way to describe a place’s position on the Earth, focusing on how far north or south it is from the Equator. In geography, latitude tells us how far north or south a place is. It is measured as an angle, from −90° at the South Pole to 90° at the North Pole, with 0° right at the Equator.

Lines of constant latitude, called parallels, run in an east-west direction. They are like circles around the Earth that are parallel to the Equator. These lines help us understand and describe locations all around the world. When we know both latitude and longitude, we can find almost any place on Earth.

Latitude helps us understand climate and weather patterns because areas with the same latitude often have similar temperatures and seasons. It is also important for navigation, mapping, and many scientific studies of our planet.

Background

Latitude helps us describe places on Earth by telling us how far north or south a point is from the Equator. To understand latitude, we imagine Earth as a simple shape, like a sphere or an ellipsoid, which is a bit squished like an orange. Real Earth isn’t a perfect shape, but these simple models help us measure positions.

We use angles to show latitude, measured in degrees north or south of the Equator. For example, a place might be 50 degrees north of the Equator. These measurements help us find locations using tools like GPS. The study of Earth’s shape and how we measure positions is called geodesy.

Latitude on the sphere

The graticule is made of lines that show constant latitude and longitude, based on Earth's rotation axis. The main points are the poles, where the axis meets the Earth's surface. The Equator is a special line around the middle of the Earth with a latitude of 0°. The North Pole has a latitude of 90° North, and the South Pole has a latitude of 90° South. Latitude tells us how far north or south a place is from the Equator.

Some important lines of latitude include the Tropic of Cancer and the Tropic of Capricorn. These lines mark the farthest points on Earth where the Sun can appear directly overhead. Between these two lines, the Sun can be directly above at different times of the year. On maps, these lines look different depending on how the map is drawn, but they always help us understand Earth's geography.

Arctic Circle	66° 34′ (66.57°) N
Tropic of Cancer	23° 26′ (23.43°) N
Tropic of Capricorn	23° 26′ (23.43°) S
Antarctic Circle	66° 34′ (66.57°) S

Normal Mercator		Transverse Mercator
	\

Latitude on the ellipsoid

Main article: Ellipsoid of revolution

Latitude tells us how far north or south a place is on Earth. Long ago, scientists discovered that Earth isn’t a perfect sphere—it’s slightly squashed, like an orange. This shape is called an ellipsoid.

When we talk about latitude on this ellipsoid, we usually mean geodetic latitude. This is the angle between an imaginary line straight up from the ground and the flat plane that circles Earth around the middle (the equator). Different maps and GPS devices might use slightly different shapes for Earth, so the exact latitude of a place can change a little. For example, the Eiffel Tower can seem to move a little depending on which model is used!

Meridian distance

Main article: Meridian arc

The space between lines of latitude changes depending on where you are on Earth. On a simple round model of Earth, each degree of latitude is about 111 kilometers everywhere. This amount changes a little when we use a more exact model of Earth's shape, but for most things, thinking of about 111 kilometers per degree is good enough.

The space between lines of longitude gets smaller the closer you get to the poles, because these lines meet there.

ϕ {\displaystyle \phi }	Δ¹ _lat	Δ¹ _long
0°	110.574 km	111.320 km
15°	110.649 km	107.550 km
30°	110.852 km	96.486 km
45°	111.132 km	78.847 km
60°	111.412 km	55.800 km
75°	111.618 km	28.902 km
90°	111.694 km	0.000 km

Auxiliary latitudes

There are six auxiliary latitudes that help with special geography and map-making problems:

Geocentric latitude
Parametric (or reduced) latitude
Rectifying latitude
Authalic latitude
Conformal latitude
Isometric latitude

These latitudes are used in advanced geography and map projects. The geocentric and parametric latitudes can help describe positions in three dimensions. The other latitudes are mainly used as steps when making flat maps from the round Earth.

The geocentric latitude is the angle between the Earth’s middle layer and a line from the center to a point. The parametric latitude helps change problems about the Earth’s shape into simpler round-ball problems.

Approximate difference from geodetic latitude (ϕ)
ϕ	Parametric β − ϕ	Authalic ξ − ϕ	Rectifying μ − ϕ	Conformal χ − ϕ	Geocentric θ − ϕ
0°	0.00′	0.00′	0.00′	0.00′	0.00′
15°	−2.88′	−3.84′	−4.32′	−5.76′	−5.76′
30°	−5.00′	−6.66′	−7.49′	−9.98′	−9.98′
45°	−5.77′	−7.70′	−8.66′	−11.54′	−11.55′
60°	−5.00′	−6.67′	−7.51′	−10.01′	−10.02′
75°	−2.89′	−3.86′	−4.34′	−5.78′	−5.79′
90°	0.00′	0.00′	0.00′	0.00′	0.00′

Latitude and coordinate systems

Latitude helps us find places on Earth by telling us how far north or south a point is from the Equator. Together with longitude, it forms a system to pinpoint any location on our planet. There are different ways to use latitude in more detailed maps and science, such as geodetic coordinates, which include height above Earth, and spherical polar coordinates, which measure distance from Earth's center. These systems help scientists understand Earth's shape and gravity.

Main article: Geodetic coordinates

Astronomical latitude

Astronomical latitude (Φ) is the angle between the equatorial plane and the true vertical direction at a point on the surface. This true vertical points in the direction of a plumb line, which shows where gravity direction is.

Astronomical latitude is found by measuring angles between the zenith and stars that have known positions. It is not the same as declination, a word astronomers use for star positions related to the celestial equator.