[Proj] proj=undef ??

[Mikael Rittri]

Hello Janne,
if I understand you right, what you want is impossible.  

If the projection is unknown, any input coordinates 
will be non-georeferenced. So, how could the datum shift
machinery do anything on coordinates that cannot be
interpreted? 

Maybe I misunderstand what you want to do.

Mikael Rittri
Carmenta
Sweden
http://www.carmenta.com

-----Original Message-----
From: proj-bounces at lists.maptools.org [mailto:proj-bounces at lists.maptools.org] On Behalf Of support.mn at elisanet.fi
Sent: den 19 juni 2011 12:30
To: proj at lists.maptools.org
Subject: [Proj] proj=undef ??

Hello,

there is a need to have an undefined projection with possible datum shift like:

proj=undef
ellps=bessel
towgs84=.....
no_defs

That would then transfer the projection input to output without doing any forward or inverse calculations even if those routines called but allowing datum shifting.

So the absolutely minimal definition would be

proj=undef
datum=undef

or shorter version

proj=undef

and that would feed all input directly to the output. Those switches would allow the end user to control the handling of the data.

So the "proj=undef" is same as not doing anything by the projection library if called but not giving any error messages about missing projection but doing all datum shifting if requested. Any ideas?

Regards: Janne.

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