[Proj] Grid shift files.

[Bas Couwenberg]

On 2016-11-01 15:54, Roger Oberholtzer wrote:
> I am trying to use a grid shift file via the C API.
> 
> It works for me in one situation, but not another:
> 
> The working one (OSTN02):
> 
> [...]
> 
> The one that is not working (RD New):
> 
> [...]
> 
> The grid shift files are in the same directory. The strange thing is 
> that
> when I trace the program execution (strace on Linux), I see that the 
> OSTN02
> file gb.gsb is opened and read. However, the one that is not working 
> (RD
> New) does not even try to open the rdtrans2008.gsb file. So it is not a
> matter of the format of the file. It is not even being accessed. (I may
> later have a file format issue. I hope not.)
> 
> I know it's old, but this is with 4.8.0. I cannot think the mechanics 
> of
> opening the file are different. Could it be related to another 
> parameter I

Sounds like you're using PROJ.4 4.9.2, and hitting this issue:

  http://lists.maptools.org/pipermail/proj/2016-February/007327.html

Which has been fixed in 4.9.3 with:

  https://github.com/OSGeo/proj.4/pull/349

Kind Regards,

Bas