Re: How long is a Chain?

["Chris Lehmann" <chrisjl@iname.com>]

David Johnson wrote in message <38562070.608B9CDB@ozemail.com.au>...
>Chris Lehmann wrote:
>
>> The official conversion for chains to metric (at least in NSW) is
>> 1 chain = 20.115 metres.  All distances were rounded to 5 millimetres
>> (0.005 metre).  The term "chainage" still survives for measurements
>> along a road or railway though it is now measured in metres.
>
>The following from Conversion Buddy Freeware Version 4.11
>
>Description  Rounding Error  Derivation
>Entered Value  Exact   Exact
>Conversion Factor  2.4855E-07   (.5/2011684).
>Reported Digits  2.4855E-06   (.5/201168).
>
>1 chains (based on US survey foot) is equivalent to: 20.1168 meters
>
>Each chain (based on US survey foot) =  (2.011 684 E1) meters.
>


Fortunately we live in Australia and have now metricated to the official
1 foot = 0.3048 metres - don't worry about the Americans, because they
always do their own thing and still can't metricate the country.

All survey measurements in NSW are accurate to 0.005 metres - no less.
In imperial times the measurements were accurate to 1/8 of an inch or
about 1/100 of a foot.

Therefore the chain is 20.115 metres long.  The official width for the once
standard "one chain wide" roads around the State is given as 20.115 metres.
We can argue forever about the accuracy of measurements so lets not
squabble over 2 milimetres or so.

Chris Lehmann

>
>--
>David Johnson
>trainman@ozemail.com.au
>http://www.ozemail.com.au/~trainman/
>
>