Car·te·sian / kärˈtēzhən/ • adj. of or relating to Descartes and his ideas.• n. a follower of Descartes.DERIVATIVES: Car·te·sian·ism / -ˌnizəm/ n.

Cartesian projection A mapping technique in which every plane in the area being mapped is projected on to a plane in the map and every line on to a line. Each point in the area under study is identified by three values, representing its location in relation to three mutually perpendicular axes (the Cartesian coordinates of the point). These coordinates are transformed mathematically into a homogeneous set of four coordinates which can then be plotted to produce a graphic representation (a map). The word ‘Cartesian’ is derived from the name of the French mathematician René Descartes (1596–1650).

Cartesian projection A technique for the mapping of space in which every plane in the area being mapped is projected on to a plane in the map and every line on to a line. Each point in the area under study is identified by three values, representing its location in relation to three mutually perpendicular axes (the Cartesian coordinates of the point). These coordinates are transformed mathematically into a homogeneous set of four coordinates which can then be plotted to produce a graphic representation (a map). The word ‘Cartesian’ is derived from the name of René Descartes (1596–1650).

Cartesian coordinates System in which the position of a point is specified by its distances from intersecting lines (axes). In the simplest type – rectangular coordinates in two dimensions – two axes are used at right angles: x and y. The position of a point is then given by a pair of numbers (x, y). The abscissa, x, is the point's distance from the y axis, measured in the direction of the x axis, and the ordinate, y, is the distance from the x axis. The axes in such a system need not be at right angles but should not be parallel to each other. Three axes represent three dimensions.

Cartesian of or relating to the ideas of the philosopher René Descartes (1596–1650), deriving from Cartesius, the Latinized form of his name.
Cartesian coordinates numbers which indicate the location of a point relative to a fixed reference point (the origin), being its shortest (perpendicular) distances from two fixed axes (or three planes defined by three fixed axes) which intersect at right angles at the origin.