The majority of technical drawing is done in 2-dimensional cartesian coordinate system. In such cases the third dimension or Z coordinate may be ignored.
Coordinates may have either positive or negative values. Each point is described by two coordinates, X and Y. In the example below the point is located in the coordinates X=5 Y=3 (X coordinate is always mentioned first). The same point can also be expressed in polar values 5.8/31, i.e. the point is the distance of 5,8 coordinate units from the origin at an angle of 31° (angle 0° is directly to the right, angle 90° is directly up).
