Computing distances between Latitude/Longitude in one step.

[johnalison]

Was taught how to do this from tables 50 years ago at Dartmouth but have yet to find a reason to do it for real.

I think there must have been traverse tables in Reeds at one time because I remember using them to calculate the course from Boulogne to Dieppe because I was too mean to buy a chart that would cover the whole area.