[Gdal-dev] OGR Spatial Questions

[pvongaza]

Hi Frank,
I've just begun my long intended projected of replacing ("gutting") my 
attempts at projection support with your OGR. What I've done is compile 
a small DLL with the core ORG spatial routines. I'm testing by reading 
Geotiffs (UTM and Albers) and trying to get Lat/Long screen coordinates. 
Running into some trouble. First I tested with some of your examples:

    OGRSpatialReference    oUTM, *poLatLong;
    OGRCoordinateTransformation *poTransform;

    oUTM.SetProjCS("UTM 17 / WGS84");
    oUTM.SetWellKnownGeogCS( "WGS84" );
    oUTM.SetUTM( 17 );

    poLatLong = oUTM.CloneGeogCS();
    poTransform = OGRCreateCoordinateTransformation( &oUTM, poLatLong );

Works fine. Then I load a geotiff and try the following:

    char *pszProjection = GTIFGetOGISDefn(gtif, &defn );
    // string looks like it should

    OGRSpatialReference oSRS;
    OGRErr i = oSRS.SetProjection( pszProjection );

To this point seem ok.

    OGRSpatialReference    *poLatLong2;
    poLatLong2 = oSRS.CloneGeogCS();

NADA, return NULL. Am I missing a key step in setting up projections 
form geotiffs? Could this be related to proj.dll (I using the 
precompiled binary from the proj4 site)? Before I start digging I'm 
hoping there is an easy solution.

This is my first go at your code and using the proj4 dll.

Thanks,
Peter