I wish to use excel to solve navigational problems. Although the use of
hours minutes and seconds provides the correct maths, I am unable to use
either negative quantities or to format the angles correctly. For example,
the latitude of 52º 12'.50N, which is 52 degrees, 12 minutes and 30 seconds
North can only be displayed as 52º 12' 33", which though correct from a
mathematical point of view is not in keeping with current practice for
writing latitude. A similar problem exists with longitude.

If I were writing this application using C++ I would write my own class
defining the data structurs and overloading the required operators. In
effect I wish to extend the data classes that excel can recognise and
handle - any ideas greatfully received.

Peter