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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Plotting Mercator or Passage Making?
From: David Pike
Date: 2016 Feb 28, 13:20 -0800
From: David Pike
Date: 2016 Feb 28, 13:20 -0800
A retired Royal Engineer Surveyor and map collector friend of mine is perplexed. For years he’d always assumed the chart referred to as PM1 stood for Plotting Mercator 1:1,000,000, as indeed I had. Recently however, he’s found a chart entitled Mercator Passage Making Chart No1 (which is in fact a 1: 2,000,000 chart). Is this just a case of one group, possibly the aviators, using the same pair of initials for one thing as a different but similar group, possibly the mariners, using the same pair of initials for a slightly different activity, or is there a more fundamental explanation? What are readers most familiar with? DaveP
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