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Latitude

Definition

Latitude is a geographic coordinate that specifies a location’s north–south position on the Earth, measured as the angle between the equatorial plane and a line from the Earth’s center to the point. Values range from 0° at the Equator to 90° at the poles, signed positive north and negative south. Lines of constant latitude are parallels. Because the Earth is not a perfect sphere, precise latitude is defined on a reference ellipsoid; geodetic latitude differs slightly from geocentric latitude. Latitude underpins cartography, navigation, climate zoning, and astronomical calculations. Combined with longitude, it enables unique global addressing. Map projections distort shapes, areas, or distances differently by latitude, which is why a degree of longitude shrinks toward the poles while a degree of latitude remains roughly constant in meters (with small variation due to ellipsoid and geoid).

Application

Navigation systems, surveying, and GPS receivers compute latitude to place features. Climate scientists relate latitude to insolation and seasons. Aviation and maritime routing consider latitude-driven winds and currents. Ecologists study latitudinal gradients in biodiversity. Web mapping APIs accept latitude/longitude for geocoding and visualization.

FAQ

Why does a degree of longitude vary with latitude?

Parallels shrink as you move poleward, so the east–west distance between meridians decreases. At the equator it is ~111 km; near the poles it approaches zero.

What is the difference between geodetic and geocentric latitude?

Geodetic latitude is measured relative to the ellipsoid normal, while geocentric uses the line to the Earth’s center. They differ by up to about a degree depending on location.

Does latitude change over time at a fixed monument?

Slightly, due to tectonics and reference-frame updates. High-precision applications handle this with epochs and velocity models.

How does latitude influence climate?

It controls sun angle and day length, shaping temperature bands and seasonality; ocean and topography then modify local expressions of those broad patterns.