[OSGeo Africa] Digitising a 1929 SG diagram

Hanlie Pretorius hanlie.pretorius at gmail.com
Wed Jan 7 04:12:42 PST 2015

Thanks to everyone who replied, in particular Chris, André and Preshen,

In case anyone is interested in the resolution, I received two similar answers:

1. Find a newer SG diagram with a defined coordinate system in the
vicinity and see if any of the points on the newer diagram correspond
to the older one. That can then be used to georeference the diagram or
transform the coordinates. (The PDF had a note on in about a 2000

2. Look for this diagram on the noting sheet (obtained from the
SGOffice) and then find the closest diagram which has modern (or at
least transformable) coordinates. The surveyor then calculates this
diagram's provisional searching coordinates from the other diagram's
coordinates ... this may involve working through a number of inbetween

In the end Chris sent me the points in a KML file and I'm not sure
exactly which method he followed.

What a great and helpful resource this list is!


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