[Proj] NTv2 info
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)
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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