[Proj] map coordinates in different coordinate system
andrew.deklerk at gmail.com
Wed Jul 8 13:46:40 EST 2009
Frank Warmerdam wrote:
> I am not sure why you say that EPSG:2054 is not a standard. It is a normal
> part of the EPSG database. However, it uses the projection method
> Transverse Mercator South Orientated. The normal software used to
> the EPSG database to a PROJ.4 dictionary does not handle this projection
> method since I'm uncertain if it is plain transverse mercator, or if there
> is also an implicit change in direction of the Y values (to southings
> instead of northings).
- Thanks for the response. Why i say it is not standard is because the proj4
definition is not there as standard with the epsg files distributed with
gdal etc. This is eveident if you browse it at
There is nothing special about 2054. It is merely transverse mercator using
WGS84 datum. if I translate coordinates using cs2cs from metres to degrees
decimal using "+proj=tmerc +lon_0=31 +datum=WGS84" the answer is correct.
Without knowing enough about projections, i am 99% sure that it is not South
I therefore first tried that, then kept on adding bits until I found someone
using the definition posted above. and yes the "o" is a typo. I also tries
without the +south, but had no luck.
So - I can ask the proj4js list, but I would love to get clarity on the
correct format proj4 format assuming that 2054 is not south orientated and
merely TM with WGS84 datum. That would help immensly. I assume it is:
"+proj=tmerc +ellips=WGS84 +datum=WGS84 +lon_0=31 +k_0=1 +units=m +no_defs"
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