[gdal-dev] Problem with OGRCreateCoordinateTransformation

[Howard Butler]

On Apr 9, 2009, at 9:38 PM, Reinaldo Escada Chohfi wrote:

> Hello all,
>
> We place this piece of code to test how coordinate transformation  
> works with OGR.
>
>        OGRSpatialReference oSourceSRS, oTargetSRS;
>        OGRCoordinateTransformation *poCT;
>        double  x1, y1;
>
>        oSourceSRS="EPSG:4326";
>        oTargetSRS="EPSG:4989";

I don't see how this could compile.  You need to instantiate  
oSourceSRS and oTargetSRS with OSRNewSpatialReference, and then use a  
call like OSRImportFromEPSG or OSRSetFromUserInput on the objects to  
get valid SpatialReferences.

>
> The program compiles fine, but it gives the following runtime error:
>
> ERROR 6: Unable to load PROJ.4 library (proj.dll), creation of
> OGRCoordinateTransformation failed.
>
> Isn't PROj.4 (proj.lib) built in OGR?
>

No, it is loaded at runtime unless you use have PROJ_FLAGS = - 
DPROJ_STATIC in your nmake.opt when you compile.  Otherwise, you must  
ensure that GDAL_DATA and/or PROJ_LIB environment variables are set,  
and the necessary data can be found in those locations *and* the  
proj.dll that was linked with GDAL at compile time is able to be found  
at runtime.