[OSGeo Africa] Kathu Coordinate System

Hanlie Pretorius hanlie.pretorius at gmail.com
Fri Jan 31 03:06:05 PST 2014

Hi Frank,

I did consider that and found an article in PositionIT that discusses
the history of the South African measurement system. [1]

The SG diagram does give lengths in 'Cape Feet' and I tried the Cape
foot conversion of 1 foot = 0.3148581 m. I converted the three points
that interest me to metres and got the following coordinates:

Point	Y (Cape ft)	X (Cape ft)	Y (m)	X (m)
W	28433.9	-88109.7	8952.64373	-27742.05273
X	23668.6	-100236.7	7452.250426	-31560.33691
Y	28967.2	-127855.6	9120.557554	-40256.37129

The converted coordinates still don't mean much to me, the X origin is
definitely not at the equator.

My client has since decided that I can just create a buffer of 31 m
around the Eskom HV line to find the servitude, but I'm attaching the
PDF of the diagram in case anyone is interested in solving this


[1]: The South African measurement system and its origin. Tomasz
Zakiewicz, CD:NGI. PositionIT, April/May 2011.

> Frank Sokolic <sokolic at worldonline.co.za> 2014/01/31 10:26 AM >>>
> Hi Hanlie,
> If the survey was done in 1968 is it not possible that the units are in
> Cape feet? Not sure when surveyors switched to using metres. Are you
> able to post a scanned copy of the survey diagram?
> Regards, Frank.
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