At 10:54 PM 2/29/2000 , Greg wrote:
>Do you Know if maps use magnetic North or true North?

Road maps I would expect to use True North.  For one thing, depending on
where you are the variation can change noticeably within a comparatively
small distance -- for example, here in RI the variation is (I should know,
but I don't) about 14-15 degrees West.  In my cruising grounds in Maine it
goes from about 16 degrees at the southern border to over 18 degrees West
in Penobscot Bay, and I think it's 20 and change at the northern border.

Marine (and I presume aeronautical) charts are printed arbitrary
orientation (almost always True North at the top) but have concentric
compass roses showing bothTrue and Magnetic printed at various points on
the chart.  I would expect topo maps to be similar except that they don't
cover enough area to need more than one set of roses per.

david
David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"