As with the measures of temporal periodicity, all three spatial measures can be converted among each other. It is important to be able to do this quickly.
If one cycle takes a distance 
, then the number of
cycles which occur per unit distance is
Because there are 
radians in one cycle, the number of radians
which we cross per unit distance are therefore
where we remind ourselves that we may drop the optional ``unit''
. Finally, combining
(1-2), we have
