# Specifying Coordinates and Using Coordinate Systems

A coordinate system determines each point of a drawing surface or entity unambiguously. The drawing tool uses the Cartesian coordinate system consisting of three coordinate axes. Axes are arranged orthogonally, crossing at the origin. All axes use the same measurements.

The coordinates of a point are derived from the distance of the point to the X-, Y-, and Z-axis (optional), respectively.

- To enter points using the keyboard, use Cartesian coordinates, Cylindrical coordinates, or Spherical formats. Enter points as absolute or relative coordinates.
- To enter points by specifying X, Y, and Z coordinates independently, use coordinate filters.

#### World Coordinate System and Custom Coordinate Systems

The drawing tool differentiates between:

- The
**World Coordinate System (WCS)**- A fixed coordinate system

WCS is a permanently installed Cartesian coordinate system used as a standard for all drawings. The X-axis measures the horizontal distance, the Y-axis measures the vertical distance from the origin. The Z-axis is orthogonal to the X- and Y-planes and measures the distance of a point to these planes. You cannot change the WCS. **Custom Coordinate Systems (CCS)**- Arbitrary coordinate systems located anywhere and oriented in any direction in the WCS

A CCS is based on the WCS, but you can define it freely. You can:- Move the origin to any point in the WCS
- Angle or turn the CCS around one or more axes in relation to the WCS
- For example, you can make the drawing plane parallel to the entities to be drawn so that drawing 3D entities is easier.