[Proj] map coordinates in different coordinate system

[Gerald I. Evenden]

On Thursday 09 July 2009 12:22:30 pm OvV_HN wrote:
> Seems to me that EPSG:2054 is the Lon_0 = 31d Hartebeesthoek_1994
> Transverse Mercator projection.
> This has a south-west orientation.
> Haven't I read somewhere that you can put a minus sign in front of the k_0
> in (lib)proj to get the axes in south-west orientation?
>
> Oscar van Vlijmen

If just changing the sign of *both* the x and y (easting-northing) is all that 
is involved with the so call "south" orientation, then a negative k_0 will do 
the trick.  Standard proj4 does not make any check on [+]k_0 (aka k).

*However,* understand that k_0 multiplication is carried out on the basic 
projected Cartesian values before the false offsets are added.

As pointed out before, the [+]south option only applies to [+]proj=utm and 
causes the addition of  10,000,000 meters to the northing (y) value so that 
it is positive in the southern hemisphere.

-- 
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist