Illumination angle
From HandWiki
In computer graphics and geography, the illumination angle of a surface with a light source (such as the Earth's surface and the Sun) is the angle between the inward surface normal and the direction of light.[1] It can also be equivalently described as the angle between the tangent plane of the surface and another plane at right angles to the light rays.[2] This means that the illumination angle of a certain point on Earth's surface is 0° if the Sun is precisely overhead and that it is 90° at sunset or sunrise.
See also
References
- ↑ Godse, A. P. (2008). Computer Graphics. Technical Publications. p. 292. ISBN 9788189411008. https://books.google.com/books?id=A1ka6gqKTD4C&pg=PA292.
- ↑ Hengl, Tomislav; Reuter, Hannes I. (2009). Geomorphometry: Concepts, Software, Applications. Developments in soil science. 33. Elsevier. p. 201. ISBN 9780123743459. https://books.google.com/books?id=iZXBeNOzOPEC&pg=PA201.