[Proj] NTv2 info

Brent Fraser bfraser at geoanalytic.com
Tue Jun 2 13:36:12 EST 2009

My government at work, *sigh*.  What they don't tell you is there is more information (including Fortran source code) on $20 CD than available for download on their website (http://www.geod.nrcan.gc.ca/tools-outils/ntv2_e.php)

Best Regards,
Brent Fraser
GeoAnalytic Inc.

Gerald I. Evenden wrote:
> Kudos to the Swiss---so far they are the only ones that seem to have format 
> information on the NTv2 correction files.
> A slap on the face with cold, wet noodles to the Canadians because I cannot 
> locate any format details on the Canadian NTv2 distribution file.  The only 
> thing I can find is the documenation of a program to access the file, which 
> deserves another slap for not being available in source form.
> I seem to get the idea that the Canadians developed this format---comments 
> please---and if they did then the designers deserve to be flogged for 8 days 
> with wet noodles for "positive east longitude."  I can't believe it!!!!  What 
> is unbelievable arrogance by whoever had that stupid---yes, *VERY* 
> stupid---idea.  I was looking at the headers of a Swiss NTv2 file and sure 
> enough, negative values for longitude.  What's in that Molson anyway?  The 
> McKenzie brothers must have been co-chairing the development commitee.
> An intersting aside demonstrated by the Swiss distribution: the compress ASCII 
> version of the NTv2 file is slightly smaller than the binary version.  
> Wouldn't it have been nice if the McKenzie brothers looked into this when 
> spec'ing the output form and saved everyone from the curse of determining 
> endian conversion?
> There is a problem with the Swiss documentation: it is in German and the 
> details of the data records is not as clear as the headers.
> Obviously, I have not exhausted all possible 4,000 google hits in looking for 
> documentation.  If someone is aware of a defining english pdf somewhere, 
> please let me know.  Thanks.

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