[GTALUG] Surveying

[Lennart Sorensen]

On Thu, Apr 21, 2016 at 01:25:39PM -0400, Stewart C. Russell wrote:
> … if you're not fussy about 117 mm difference. Surveyors tend to be.
> 
> The only unit of measurement I know of that was deliberately designed to
> be friendly for both metric and not-metric* is the HP-GL unit. It's 1/40
> mm, or exactly 1/1016 inch.

Well 1/40 mm * 25.4 mm/inch = 1/1016 inch.  Of course, since 40*25.4
= 1016.  I don't see how this is a nice fraction of an inch.  It would
be no different than doing:
1/100 mm * 25.4 mm/inch = 1/2540 inch.  Just as nice.

Clearly the unit was designed to be convinient for metric only.

And it only works out at all cleanly because the inch was redefined to
be 25.4 mm at some point in time.  It used to be slightly different
(the US and UK versions being slightly on either side of 25.4 mm).

-- 
Len Sorensen