Re: Great Lakes Boaters, Polyconic charts, mph
Originally Posted by Hartley18
Righto.. What's this then?? Looks like nautical miles (and tenths) to me:
I understand that the Polyconic nature of the chart means that lines of lattitude and longtitude aren't necessarily straight up that part of the world, but don't get me wrong, I'm happy to learn something new.
It is the latitude scale, used to measure distance on a Mercator projection.
Polyconic projections are common in the Great Lakes of Canada and the US.
ISPA Yachtmaster Offshore Instructor Evaluator
CYA Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
As I sail, I praise God, and care not. (Luke Foxe)