ogr_srs_proj4.cpp

用于读取TAB、MIF、SHP文件的类

        
        SetGeogCS( "unnamed ellipse", "unknown", "unnamed",
                   dfSemiMajor, dfInvFlattening,
                   pszPM, dfFromGreenwich );
        
        bFullyDefined = TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Handle TOWGS84 conversion.                                      */
/* -------------------------------------------------------------------- */
    pszValue = CSLFetchNameValue(papszNV, "towgs84");
    if(pszValue!=NULL)
    {
        char **papszToWGS84 = CSLTokenizeStringComplex( pszValue, ",", 
                                                        FALSE, TRUE );

        if( CSLCount(papszToWGS84) >= 7 )
            SetTOWGS84( atof(papszToWGS84[0]), 
                        atof(papszToWGS84[1]), 
                        atof(papszToWGS84[2]), 
                        atof(papszToWGS84[3]), 
                        atof(papszToWGS84[4]), 
                        atof(papszToWGS84[5]), 
                        atof(papszToWGS84[6]) );
        else if( CSLCount(papszToWGS84) >= 3 )
            SetTOWGS84( atof(papszToWGS84[0]), 
                        atof(papszToWGS84[1]), 
                        atof(papszToWGS84[2]) );
        else
            CPLError( CE_Warning, CPLE_AppDefined, 
                      "Seemingly corrupt +towgs84 option (%s), ignoring.", 
                      pszValue );
                        
        CSLDestroy(papszToWGS84);
    }

/* -------------------------------------------------------------------- */
/*      Linear units translation                                        */
/* -------------------------------------------------------------------- */
    if( IsProjected() || IsLocal() )
    {
        pszValue = CSLFetchNameValue(papszNV, "to_meter");

        if( pszValue != NULL && atof(pszValue) > 0.0 )
        {
            SetLinearUnits( "unknown", atof(pszValue) );
        }
        else if( (pszValue = CSLFetchNameValue(papszNV, "units")) != NULL )
        {
            if( EQUAL(pszValue,"meter" ) || EQUAL(pszValue,"m") )
                SetLinearUnits( SRS_UL_METER, 1.0 );
            else if( EQUAL(pszValue,"us-ft" ) )
                SetLinearUnits( SRS_UL_US_FOOT, atof(SRS_UL_US_FOOT_CONV) );
            else if( EQUAL(pszValue,"ft" ) )
                SetLinearUnits( SRS_UL_FOOT, atof(SRS_UL_FOOT_CONV) );
            else if( EQUAL(pszValue,"yd" ) )
                SetLinearUnits( pszValue, 0.9144 );
            else if( EQUAL(pszValue,"us-yd" ) )
                SetLinearUnits( pszValue, 0.914401828803658 );
            else // This case is untranslatable.  Should add all proj.4 unts
                SetLinearUnits( pszValue, 1.0 );
        }
    }

/* -------------------------------------------------------------------- */
/*      Adjust linear parameters into PROJCS units if the linear        */
/*      units are not meters.                                           */
/* -------------------------------------------------------------------- */
    if( GetLinearUnits() != 1.0 && IsProjected() )
    {
        OGR_SRSNode *poPROJCS = GetAttrNode( "PROJCS" );
        int  i;

        for( i = 0; i < poPROJCS->GetChildCount(); i++ )
        {
            OGR_SRSNode *poParm = poPROJCS->GetChild(i);
            if( !EQUAL(poParm->GetValue(),"PARAMETER") 
                || poParm->GetChildCount() != 2 )
                continue;

            const char *pszParmName = poParm->GetChild(0)->GetValue();

            if( IsLinearParameter(pszParmName) )
                SetNormProjParm(pszParmName,GetProjParm(pszParmName));
        }        
    }


/* -------------------------------------------------------------------- */
/*      do we want to insert a PROJ.4 EXTENSION item?                   */
/* -------------------------------------------------------------------- */
    if( strstr(pszProj4,"wktext") != NULL )
        SetExtension( GetRoot()->GetValue(), "PROJ4", pszProj4 );
        
    CSLDestroy( papszNV );
    
    return OGRERR_NONE;
}


/************************************************************************/
/*                          OSRExportToProj4()                          */
/************************************************************************/

OGRErr CPL_STDCALL OSRExportToProj4( OGRSpatialReferenceH hSRS, 
                                     char ** ppszReturn )

{
    *ppszReturn = NULL;

    return ((OGRSpatialReference *) hSRS)->exportToProj4( ppszReturn );
}

/************************************************************************/
/*                           exportToProj4()                            */
/************************************************************************/

/**
 * Export coordinate system in PROJ.4 format.
 *
 * Converts the loaded coordinate reference system into PROJ.4 format
 * to the extent possible.  The string returned in ppszProj4 should be
 * deallocated by the caller with CPLFree() when no longer needed.
 *
 * LOCAL_CS coordinate systems are not translatable.  An empty string
 * will be returned along with OGRERR_NONE.  
 *
 * This method is the equivelent of the C function OSRExportToProj4().
 *
 * @param ppszProj4 pointer to which dynamically allocated PROJ.4 definition 
 * will be assigned. 
 *
 * @return OGRERR_NONE on success or an error code on failure. 
 */

OGRErr OGRSpatialReference::exportToProj4( char ** ppszProj4 ) const

{
    char        szProj4[512];
    const char *pszProjection = GetAttrValue("PROJECTION");

    szProj4[0] = '\0';

/* -------------------------------------------------------------------- */
/*      Do we have a PROJ.4 override definition?                        */
/* -------------------------------------------------------------------- */
    const char *pszPredefProj4 = GetExtension( GetRoot()->GetValue(), 
                                               "PROJ4", NULL );
    if( pszPredefProj4 != NULL )
    {
        *ppszProj4 = CPLStrdup( pszPredefProj4 );
        return OGRERR_NONE;
    }

/* -------------------------------------------------------------------- */
/*      Get the prime meridian info.                                    */
/* -------------------------------------------------------------------- */
    const OGR_SRSNode *poPRIMEM = GetAttrNode( "PRIMEM" );
    double dfFromGreenwich = 0.0;

    if( poPRIMEM != NULL && poPRIMEM->GetChildCount() >= 2 
        && atof(poPRIMEM->GetChild(1)->GetValue()) != 0.0 )
    {
        dfFromGreenwich = atof(poPRIMEM->GetChild(1)->GetValue());
    }

/* ==================================================================== */
/*      Handle the projection definition.                               */
/* ==================================================================== */

    if( pszProjection == NULL && IsGeographic() )
    {
        sprintf( szProj4+strlen(szProj4), "+proj=longlat " );
    }
    else if( pszProjection == NULL && !IsGeographic() )
    {
        // LOCAL_CS, or incompletely initialized coordinate systems.
        *ppszProj4 = CPLStrdup("");
        return OGRERR_NONE;
    }
    else if( EQUAL(pszProjection,SRS_PT_CYLINDRICAL_EQUAL_AREA) )
    {
        sprintf( szProj4+strlen(szProj4),
           "+proj=cea +lon_0=%.16g +lat_ts=%.16g +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_STANDARD_PARALLEL_1,0.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_BONNE) )
    {
        sprintf( szProj4+strlen(szProj4),
           "+proj=bonne +lon_0=%.16g +lat_1=%.16g +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_STANDARD_PARALLEL_1,0.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_CASSINI_SOLDNER) )
    {
        sprintf( szProj4+strlen(szProj4),
           "+proj=cass +lat_0=%.16g +lon_0=%.16g +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_NEW_ZEALAND_MAP_GRID) )
    {
        sprintf( szProj4+strlen(szProj4),
                 "+proj=nzmg +lat_0=%.16g +lon_0=%.16g +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_TRANSVERSE_MERCATOR) ||
             EQUAL(pszProjection,SRS_PT_TRANSVERSE_MERCATOR_MI_21) ||
             EQUAL(pszProjection,SRS_PT_TRANSVERSE_MERCATOR_MI_22) ||
             EQUAL(pszProjection,SRS_PT_TRANSVERSE_MERCATOR_MI_23) ||
             EQUAL(pszProjection,SRS_PT_TRANSVERSE_MERCATOR_MI_24) ||
             EQUAL(pszProjection,SRS_PT_TRANSVERSE_MERCATOR_MI_25) )
    {
        int bNorth;
        int nZone = GetUTMZone( &bNorth );

        if( nZone != 0 )
        {
            if( bNorth )
                sprintf( szProj4+strlen(szProj4), "+proj=utm +zone=%d ", 
                         nZone );
            else
                sprintf( szProj4+strlen(szProj4),"+proj=utm +zone=%d +south ", 
                         nZone );
        }            
        else
            sprintf( szProj4+strlen(szProj4),
             "+proj=tmerc +lat_0=%.16g +lon_0=%.16g +k=%f +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_MERCATOR_1SP) )
    {
        sprintf( szProj4+strlen(szProj4),
           "+proj=merc +lon_0=%.16g +k=%f +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_MERCATOR_2SP) )
    {
        sprintf( szProj4+strlen(szProj4),
           "+proj=merc +lon_0=%.16g +lat_ts=%.16g +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_STANDARD_PARALLEL_1,0.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_OBLIQUE_STEREOGRAPHIC) )
    {
        sprintf( szProj4+strlen(szProj4),
         "+proj=sterea +lat_0=%.16g +lon_0=%.16g +k=%f +x_0=%.16g +y_0=%.16g ",
//         "+proj=stere +lat_0=%.16g +lon_0=%.16g +k=%f +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_STEREOGRAPHIC) )
    {
        sprintf( szProj4+strlen(szProj4),
           "+proj=stere +lat_0=%.16g +lon_0=%.16g +k=%f +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_POLAR_STEREOGRAPHIC) )
    {
        if( GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0) >= 0.0 )
            sprintf( szProj4+strlen(szProj4),
                     "+proj=stere +lat_0=90 +lat_ts=%.16g +lon_0=%.16g "
                     "+k=%.16g +x_0=%.16g +y_0=%.16g ",
                     GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,90.0),
                     GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                     GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0),
                     GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                     GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
        else
            sprintf( szProj4+strlen(szProj4),
                     "+proj=stere +lat_0=-90 +lat_ts=%.16g +lon_0=%.16g "
                     "+k=%.16g +x_0=%.16g +y_0=%.16g ",
                     GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,-90.0),
                     GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                     GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0),
                     GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                     GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_EQUIRECTANGULAR) )
    {
        sprintf( szProj4+strlen(szProj4),
                 "+proj=eqc +lat_ts=%.16g +lon_0=%.16g +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_GNOMONIC) )
    {
        sprintf( szProj4+strlen(szProj4),
                 "+proj=gnom +lat_0=%.16g +lon_0=%.16g +x_0=%.16g +y_0=%.16g ",
                 GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),
                 GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),
                 GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),
                 GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );
    }

    else if( EQUAL(pszProjection,SRS_PT_ORTHOGRAPHIC) )
    {
        sprintf( szProj4+strlen(szProj4),