[gdal-dev] GDAL and PROJ.4

[Ben Discoe]

> From: warmerda at s...
> Subject: Re: [gdal-dev] GDAL and PROJ.4
>
> It is my intention to prepare a proper PROJ.4 binary distribution
> for Windows at some point.

That would be great.

> To successfully do the datum shift, PROJ.4 needs to be able to find the
> datum shift files. On windows this process is a bit more challenging than
> with a default unix install. You should be able to define the PROJ_LIB
> environment variable, and point it to the PROJ\NAD directory.

Is this 'PROJ_LIB' necessary to "build" the datum shift files, or necessary
at runtime? It is a bit much for me to expect Windows end-users to set an
environment variable to run the top-level software.

> Also, ensure that you have "preprocessed" the datum shift files.

I admit i haven't gone too deeply into the PROJ docs, but i'm quite puzzled
why PROJ requires this step, when the similar 'gctpc' package does Datum
conversion and does not need any similar step.

> With the latest PROJ.4 from CVS you should be able to "nmake /f
> makefile.vc nadshift"
> in the PROJ\SRC directory to process the datum shift files in PROJ\NAD.

When i try that, i get the error:
C:\APIs\proj\nad>..\src\nad2bin.exe < conus.lla conus
The system cannot find the file specified.

Indeed, there is no file 'conus.lla' in the PROJ cvs.

> In the longer term I hope this process will be smoother, especially the
> mechanisms for finding the datum shift files.

Please! Can they be 'compiled in' to the library, or perhaps whatever
'gctpc' does?

Thanks,
Ben