# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: Coordinate precision
Date: 2019 Jul 3, 00:40 -0400
Frank, Thanks for clarifying Bob's link.

That cartoon illustrates something we have talked about in the past.  Just because we have 15 decimal digits on our calculator doesn't mean they make sense.

At 3 decimal digits (.001° vs .002°), we are discussing just over 100 meters.  That's really good enough for SAR, and plenty good enough for CN.  That value is better than 0.1' , our nominal least significant  digit.  The true value is 0.06' or 3.6".

At 0.000,000,000,000,001°, its 4 billionths of an inch.  Serious overkill, but hey, your calculator said it, so it must be true.  SAR doesn't need it.  You don't need it.  Its at least 12 orders of magnitude beyond reasonable.

On Tue, Jul 2, 2019, 9:17 PM Frank Reed <NoReply_FrankReed@fer3.com> wrote:

Bob Crawley posted a copy of a clever cartoon earlier today. Because of a quirk in the way it was posted, it took interminably long to load, taxing the limits of most web browsers and email clients. Here is a plain vanilla link to it at the source: coordinate precision cartoon.

Frank Reed

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