In geodesy, conversion among different

**geographic****coordinate**systems is made necessary by the different**geographic****coordinate**systems in use across the world and over time. .**Coordinate**conversion is composed of a number of different types of conversion: format change of**geographic**coordinates, conversion of**coordinate**systems, or transformation to different geodetic datuAnother common

**coordinate system**for the plane is the polar**coordinate system**. A point is chosen as the pole and a ray from this point is taken as the polar axis.For a given angle θ, there is a single line through the pole whose angle with the polar axis is θ (measured counterclockwise from the axis to the line).