Dear Chris > I would argue that the rhumb line is itself virtually obsolete.
I readily accept your line of thought, but a rhumb line legacy is still very much with us. I refer, of course, to Mercator's Projection where all straight lines are projections of Rhumb Lines. Mercator's is probably the best known of all map projections and it will be a while before it becomes obsolete. In particular, all British Ordnance Survey maps use it though their base great circle is not the equator but a line of longitude through the Isle of Wight. Mercator's Projection is quite a mathematical challenge and it and rhumb lines lead to interesting puzzles. For example, if you set out from Greenwich and follow a strict north-EASTerly course you will eventually pass over Canada. Of course, you will also cross the Greenwich meridian an indefinite number of times as you approach, but never quite reach, the north pole. Frank H. King Cambridge, U.K. -
