Azimutal

Azimutal is an adjective related to the azimuth, the angle measured in the horizontal plane from a reference direction, typically north. The term is used in geography, astronomy, cartography and physics to describe direction, symmetry or measurements defined with respect to the horizontal azimuth around a vertical axis.

In navigation and surveying, an azimuth is the clockwise angle from north to a point of interest, usually expressed in degrees from 0 to 360. Elevation or altitude is a separate angle measured above the horizon. Azimuths are fundamental to compasses, bearings, radar, telescope pointing, and astronomical positioning.

In cartography, azimuthal projections are planar map projections created by projecting the sphere onto a plane from a chosen center point or along a central line. They preserve azimuths (directions) from the center point, and are used for radio planning, astronomy and navigation. Common variants include the azimuthal equidistant projection, which preserves distances from the center; the stereographic projection, which preserves angles; and the orthographic projection, which provides a perspective view of the globe. In many azimuthal projections, great-circle routes through the center appear as straight lines.

In physics and mathematics, azimuthal symmetry describes invariance under rotation about a fixed axis. The term also appears in quantum mechanics as the azimuthal quantum number l, which labels the orbital angular momentum of electrons and helps determine orbital shapes and energy interactions alongside other quantum numbers.