[Proj] Potentially (theoretically) dangerous changes in Proj4 internal routines that affect the end results..

[support at mnspoint.com]

Hello,

why not just add a new projection called "utm2" or "newutm" or "xutm" .. 
and use it like "proj=utm2" etc. I would like more if the new utm was 
called different so that the old references would stay where they always 
been.. just to stay consistent..

Regards Janne.

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Thomas Knudsen kirjoitti 02.11.2015 14:15:
> If memory serves me right, you should use something like +proj=tmerc
> +x_0=500000 +lon_0=...   +scale=0.9996 to invoke the Snyder algorithm
> (fully analogous to what you had to do up until now to get utm using
> +proj=etmerc)
> 
> /thomas
> 
> 2015-11-02 11:42 GMT+01:00  <support at mnspoint.com>:
>> Hello,
>> 
>> basically it is always ok to switch to any calculation that is more 
>> accurate
>> or more formally correct ... but there should also be some kind of a 
>> method
>> to stay downwards compatible. At least some methods or go arounds to 
>> stay
>> compatible with old version should be given to users?!
>> 
>> What proj4 declarations should be used to keep the old calculation in
>> effect?! etc..
>> 
>> Regards: Janne.
>> 
>> -----------------------------------------------
>> 
>> Thomas Knudsen kirjoitti 28.10.2015 15:56:
>> 
>> As described in a recent thread, for the next release, proj.4 will 
>> switch
>> the default transverse mercator implementation from tmerc to 
>> etmerc......
>> 
>>