Boost Community,

I'm trying to create a custom velocity unit.  I would like to create a unit that is in nautical miles per hour to represent my speed value.  If I use pound_force.hpp as an example of units with more than one dimension I can create the following.

BOOST_UNITS_DEFINE_BASE_UNIT_WITH_CONVERSIONS(metric, nautical_mile_per_hour, "nautical mile per hour", "nmi h^-1", factor, si::velocity, ???);

If this is the right track, what id would I use and how do I know that it is unique?

This seems forced.  I would rather define this unit in terms of meters per second.  Nautical miles is already in terms of meters and hours is also defined as a scale of seconds.  Can I somehow use these two already defined units to create the new unit?  How would I do this?

Ryan