Projection or projections may refer to:

Physics

Projection (physics) The vector projection (also known as the vector component or vector resolution) of a Vector (geometry), vector on (or onto) a nonzero vector is the orthogonal projection of onto a straight line parallel to . The projection of onto is often ...

, the action/process of light, heat, or sound reflecting from a surface to another in a different direction * The display of images by a

projector A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer type ...

Optics, graphics, and cartography

Map projection In cartography, a map projection is any of a broad set of Transformation (function) , transformations employed to represent the curved two-dimensional Surface (mathematics), surface of a globe on a Plane (mathematics), plane. In a map projection, ...

, reducing the surface of a three-dimensional planet to a flat map *

Graphical projection A 3D projection (or graphical projection) is a design technique used to display a three-dimensional (3D) object on a two-dimensional (2D) surface. These projections rely on visual perspective and aspect analysis to project a complex object f ...

, the production of a two-dimensional image of a three-dimensional object

Chemistry

* Fischer projection, a two-dimensional representation of a three-dimensional organic molecule * Haworth projection, a way of writing a structural formula to represent the cyclic structure of monosaccharides * Natta projection, a way to depict molecules with complete stereochemistry in two dimensions in a skeletal formula * Newman projection, a visual representation of a chemical bond from front to back

Mathematics

* Projection (mathematics), any of several different types of geometrical mappings **

Projection (linear algebra) In linear algebra and functional analysis, a projection is a linear transformation P from a vector space to itself (an endomorphism) such that P\circ P=P. That is, whenever P is applied twice to any vector, it gives the same result as if it ...

, a linear transformation from a vector space to itself such that ** Projection (set theory), one of two closely related types of functions or operations in set theory ** Projection (measure theory), use of a projection map in measure theory **

3D projection A 3D projection (or graphical projection) is a Design, design technique used to display a three-dimensional (3D) object on a two-dimensional (2D) surface. These projections rely on perspective (graphical), visual perspective and aspect analysi ...

, any method of mapping three-dimensional points to a two-dimensional plane ** Vector projection, orthogonal projection of a vector onto a straight line **

Projection (relational algebra) In relational algebra, a projection is a unary operation written as \Pi_( R ), where R is a relation and a_1,...,a_n are attribute names. Its result is defined as the set obtained when the components of the tuples in R are restricted to the se ...

, a type of unary operation in relational algebra * Projection method (fluid dynamics), means of numerically solving time-dependent incompressible fluid-flow problems

Biology

* Projection areas, areas of the brain where sensory processing occurs * Projection fiber, in neuroscience, white matter fibers that connect the cortex to the lower parts of the brain or the spinal cord

Linguistics

* Projection (linguistics), grammatical trait inheritance from a head to a phrasal category *

Projection principle In linguistics, the projection principle is a stipulation proposed by Noam Chomsky as part of the phrase structure component of Generative grammar, generative-transformational grammar. The projection principle is used in the derivation of phrases ...

in syntax * Projection of

presupposition In linguistics and philosophy, a presupposition is an implicit assumption about the world or background belief relating to an utterance whose truth is taken for granted in discourse. Examples of presuppositions include: * ''Jane no longer writes ...

s in linguistics

Arts and entertainment

* "Projections" (''Star Trek: Voyager''), an episode of the television series ''Star Trek: Voyager'' * ''Projections'' (The Blues Project album), 1966 * ''Projections'' (John Handy album), 1968 * ''Projections'' (film), 2013 Croatian film

Other uses

* Projection (alchemy), process in Alchemy * ''Projections'' (journal), an interdisciplinary academic journal related to cinema and visual media * Power projection, the capacity of a state to implement policy by means of force, or the threat thereof *

Psychological projection Psychological projection is a defence mechanism of alterity concerning "inside" ''content'' mistaken to be coming from the "outside" Other. It forms the basis of empathy by the projection of personal experiences to understand someone else's su ...

, or "Freudian projection", a defense mechanism in which one attributes to others one's own unacceptable or unwanted attributes, thoughts, or emotions * Social projection, a cognitive bias that leads people to believe others are similar to themselves *

Forecasting Forecasting is the process of making predictions based on past and present data. Later these can be compared with what actually happens. For example, a company might Estimation, estimate their revenue in the next year, then compare it against the ...

, making predictions of the future based on past and present data * Population projection, in the field of demography, an estimate of a future population