Direction (geometry)

The shape of each panel of this road sign, and the broken lines at the ends, represents an arrow; a space-consuming central bar of the arrow sign is dispensed with.

Direction is the information contained in the relative position of one point with respect to another point without the distance information. Directions may be either relative to some indicated reference (the violins in a full orchestra are typically seated to the left of the conductor), or absolute according to some previously agreed upon frame of reference (New York City lies due west of Madrid). Direction is often indicated manually by an extended index finger or written as an arrow. On a vertically oriented sign representing a horizontal plane, such as a road sign, "forward" is usually indicated by an upward arrow. Mathematically, direction may be uniquely specified by a unit vector, or equivalently by the angles made by the most direct path with respect to a specified set of axes.

In Euclidean and affine geometry, the direction of a subspace is the vector space associated to this subspace. In the case of a subspace of dimension one (that is a line) the direction vectors are the nonzero vectors of this vector space.

See also

This article is issued from Wikipedia - version of the 6/10/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.