NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Accuracy/precision in plotting tools.
From: Herbert Prinz
Date: 2004 Mar 30, 20:49 -0500
From: Herbert Prinz
Date: 2004 Mar 30, 20:49 -0500
I have to make corrections to my earlier post to avoid potential confusion. I wrote: > Check the graduation with dividers. But if you use a compass, use the same > section of the compass for the different quadrants of the rose, and then vice > versa. This will tell you immediately whether the rose or the compass is the > culprit of any divergence. Substitute "protractor" for "compass". When will I learn English? And I wrote > Now, on your plotting sheet, draw a horizontal baseline of 100 mm from the > center towards east. This corresponds to some 96 nm, or thereabouts, on a DMAAC > VPOSX001 (3 inch per deg lat). 100 millimeter actually correspond to 78.7 nautical miles on such a plotting sheet. However, this error does not affect the subsequent computation. More importantly, I should have made clear that the plotting sheet is supposed to be centered on latitude 40 deg. This is the reason why these 100 mm correspond to 101.5 mm at lat 41 deg. Herbert Prinz