There are many kinds of coordinate systems, such as Cartesian coordinate system, plane polar coordinate system, cylindrical coordinate system (or cylindrical coordinate system) and spherical coordinate system (or spherical coordinate system). The coordinate system commonly used in middle school physics is rectangular coordinate system, or orthogonal coordinate system.

Broadly speaking, all abstract concepts of things exist with reference to the coordinate system to which they belong, and the same thing will be represented by different abstract concepts in different coordinate systems. The number of related abstract concepts expressed in the coordinate system, that is, the number of coordinate axes, is the dimension of the space where things are located.

Application:

It is very important to imagine a graph as the trajectory of a point! It changed the traditional geometric method from the guiding ideology. Descartes, according to his own ideas, first established the coordinates of moving points in geometry, and founded analytic geometry which is related to geometry and algebra. In analytic geometry, the coordinates of moving points become variables, which is the first time that mathematics introduces variables.

Engels spoke highly of Descartes' work. He said, "The turning point in mathematics is Cartesian variables. With variables, movement enters mathematics, with variables, dialectics enters mathematics. "

Coordinate method is widely used in daily life. Such as chess and chess positioning; The concept of coordinates is used in the stands of cinemas, theaters, gymnasiums, seats in train carriages and room numbers of high-rise buildings.