In
vector calculus, a
vector field is an assignment of a
vector to each point in a subset of
space. A vector field in the plane, for instance, can be visualized as a collection of arrows with a given magnitude and direction each attached to a point in the plane. Vector fields are often used to model, for example, the speed and direction of a moving fluid throughout space, or the strength and direction of some
force, such as the
magnetic or
gravitational force, as it changes from point to point.