<P> There are two conventions used in setting down the equations of any given projection . For example, the equirectangular cylindrical projection may be written as </P> <Dl> <Dd> cartographers: x = a λ (\ displaystyle x = a \ lambda) y = a φ (\ displaystyle y = a \ phi) </Dd> <Dd> mathematicians: x = λ (\ displaystyle x = \ lambda) y = φ (\ displaystyle y = \ phi) </Dd> </Dl> <Dd> cartographers: x = a λ (\ displaystyle x = a \ lambda) y = a φ (\ displaystyle y = a \ phi) </Dd> <Dd> mathematicians: x = λ (\ displaystyle x = \ lambda) y = φ (\ displaystyle y = \ phi) </Dd>

Two ways that scale can be expressed on a map