What are the principal datums and projections used in South Africa including the names of geodetic datums and their projections?
There are two principal datums used in South Africa. These include Hartebeesthoek94 and Cape.
Hartebeesthoek94 Datum is the official geodetic datum for South Africa.
The Cape datum is the older of the two is no longer used. This references the Clarke 1880 ellipsoid and it was developed by Sir Thomas Maclear and Sir David Gill in the later 19th - early 20th Century.
Hartebeesthoek94 is the datum currently in use in South Africa. Since 1st January 1999 the official coordinate system for South Africa is the Hartebeesthoek94 geodetic datum but referencing the WGS84 ellispoid with the International Terrestrial Reference Frame 1991 coordinates of the Hartebeesthoek Radio Astronomy Observatory Telescope used as the origin of this system.
The common projections seen in South Africa use the Transverse Mercator Projection and can bee seen in some software as "Hartebeesthoek94 Lo15" where the "Lo15" indicates the zone name (named after the value of its origin, similarly to UTM Zones).
A list of coordinate systems for South Africa can be found on epsg.io.