An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A map projection on which the → azimuths of all points are shown correctly with respect to the center. A plane tangent to one of the Earth's poles is the basis for polar azimuthal projection.

→ azimuthal; → projection.

A method for estimating the real orientation of a field and/or related velocities/separations from two-dimensional images.

→ de-; → projection.

The projection of a spherical surface onto a plane through a point. A gnomonic → map projection displays all great circles as straight lines, and therefore indicates the shortest path between two points. Small circles are projected as conic sections.

→ gnomon; → -ic; → projection.

The theory and method of transforming the features, geometry, and topology on a sphere surface (in particular the spherical Earth) onto a plane.

→ map; → projection.

1) The act, process, or result of projecting.
2) The act of reproducing on a surface, by optical means, a remote image on a film, slide, etc.

Verbal noun of → project.

A graphical method of depicting three-dimensional geometrical objects in two dimensions. In a → planispheric astrolabe, it is the projection of a point of the celestial sphere onto the equatorial plane, as seen from one of the poles. The center of projection is the South pole for the northern hemisphere, and the North pole for the southern hemisphere. In this operation the projection of any circle of the sphere remains a circle on the projection plane and moreover the projection does not alter angles.

→ stereographic; → projection