[Proj] Altering the +south paramter using UTM

Gerald I. Evenden gerald.evenden at verizon.net
Wed Dec 21 22:13:11 EST 2005

On Wednesday 21 December 2005 09:32 am, Chris Tweedie wrote:
> Hi Frank/Others .
> Hopefully this is a quick question but I am in the process of trying to
> formulate the right parameters to transform data held in a modified UTM
> Zone 50 projection (epsg 28350) to GDA94 (epsg4283)
> The only modification is to the false northing, so instead of 10,000,000
> which I assume is the default value for +south, this data is stored with
> 16,000,000. I have been trying the following but no matter what I try I
> don't seem to be able to modify the default value using +south= or +y_0=.
> Is there a dependency to specify any other parameters with it?
> Eg.
> cs2cs +proj=utm +zone=50 +y_0=16000000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0
> +units=m +to +proj=longlat +ellps=GRS80

+y_0 is not allowed in UTM.  For southern hemisphere specify +south.
Sorry, but UTM has a strict meaning in proj.  Proj tries very hard to prevent
missuse of the definition.

If you MUST use 16,000,000 then you MUST use +proj=tmerc.

> Chris Tweedie

Jerry and the low riders:Daisy May and Joshua
"The being cannot be termed rational or virtuous,
who obeys any authority, but that of reason."
---Mary Wollstonecraft 1792

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