Re: How long is a Chain?

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

Ben O'Regan wrote in message <385483a3@news.hunterlink.net.au>...
>OK,
>
>I know how long a piece of string is, but how long is a chain?
>
>I've got a conversion table explaining inches, feet, yards, rods, furlongs,
>miles and leagues but not chains.
>
>(I recall that surveyors used chains that were 100 something long while
>engineers used chains that were 100 something else long).
>
In the early 1970's, when I first started work as a surveyor's assistent,
the metric system was just being introduced.  All the work we had done
previously was measured in decimal feet, or if the plan was shown as
chains, and was big enough, then we'd measure in chains and links.
Using chains was much easier because it was inherently decimal and
made calculations much easier.  Try multiplying 10 ft 6 1/8 inches
by 54 ft 7 3/4 inches - that's also why we measured in decimal fett and
then converted to feet and inches.

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.

I can still recall working in Darling Harbour Goods Yard when my firm
was surveying for the Western Distributor.  It was indeed a trying time
when plans could be in three different measuring system (feet, chains
and metres) and as has been stated all the old plans are shown in the
relevant measuring system.

Chris Lehmann
Former Surveyor, GIS specialist, etc