ogrspatialreference.cpp

mitab,读取MapInfo的地图文件

    bNormInfoSet = FALSE;

    poCS = GetAttrNode( "GEOGCS" );

    if( poCS == NULL )
        return OGRERR_FAILURE;

    OGRPrintDouble( szValue, dfInRadians );

    if( poCS->FindChild( "UNIT" ) >= 0 )
    {
        poUnits = poCS->GetChild( poCS->FindChild( "UNIT" ) );
        poUnits->GetChild(0)->SetValue( pszUnitsName );
        poUnits->GetChild(1)->SetValue( szValue );
    }
    else
    {
        poUnits = new OGR_SRSNode( "UNIT" );
        poUnits->AddChild( new OGR_SRSNode( pszUnitsName ) );
        poUnits->AddChild( new OGR_SRSNode( szValue ) );
        
        poCS->AddChild( poUnits );
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                         OSRSetAngularUnits()                         */
/************************************************************************/

OGRErr OSRSetAngularUnits( OGRSpatialReferenceH hSRS, 
                           const char * pszUnits, double dfInRadians )

{
    return ((OGRSpatialReference *) hSRS)->SetAngularUnits( pszUnits, 
                                                            dfInRadians );
}

/************************************************************************/
/*                          GetAngularUnits()                           */
/************************************************************************/

/**
 * Fetch angular geographic coordinate system units.
 *
 * If no units are available, a value of "degree" and SRS_UA_DEGREE_CONV 
 * will be assumed.  This method only checks directly under the GEOGCS node
 * for units.
 *
 * This method does the same thing as the C function OSRGetAngularUnits().
 *
 * @param ppszName a pointer to be updated with the pointer to the 
 * units name.  The returned value remains internal to the OGRSpatialReference
 * and shouldn't be freed, or modified.  It may be invalidated on the next
 * OGRSpatialReference call. 
 *
 * @return the value to multiply by angular distances to transform them to 
 * radians.
 */

double OGRSpatialReference::GetAngularUnits( char ** ppszName ) const

{
    const OGR_SRSNode *poCS = GetAttrNode( "GEOGCS" );

    if( ppszName != NULL )
        *ppszName = "degree";
        
    if( poCS == NULL )
        return atof(SRS_UA_DEGREE_CONV);

    for( int iChild = 0; iChild < poCS->GetChildCount(); iChild++ )
    {
        const OGR_SRSNode     *poChild = poCS->GetChild(iChild);
        
        if( EQUAL(poChild->GetValue(),"UNIT")
            && poChild->GetChildCount() >= 2 )
        {
            if( ppszName != NULL )
                *ppszName = (char *) poChild->GetChild(0)->GetValue();
            
            return atof( poChild->GetChild(1)->GetValue() );
        }
    }

    return 1.0;
}

/************************************************************************/
/*                         OSRGetAngularUnits()                         */
/************************************************************************/

double OSRGetAngularUnits( OGRSpatialReferenceH hSRS, char ** ppszName )
    
{
    return ((OGRSpatialReference *) hSRS)->GetAngularUnits( ppszName );
}

/************************************************************************/
/*                 SetLinearUnitsAndUpdateParameters()                  */
/************************************************************************/

/**
 * Set the linear units for the projection.
 *
 * This method creates a UNITS subnode with the specified values as a
 * child of the PROJCS or LOCAL_CS node.   It works the same as the
 * SetLinearUnits() method, but it also updates all existing linear
 * projection parameter values from the old units to the new units. 
 *
 * @param pszUnitsName the units name to be used.  Some preferred units
 * names can be found in ogr_srs_api.h such as SRS_UL_METER, SRS_UL_FOOT 
 * and SRS_UL_US_FOOT. 
 *
 * @param dfInMeters the value to multiple by a length in the indicated
 * units to transform to meters.  Some standard conversion factors can
 * be found in ogr_srs_api.h. 
 *
 * @return OGRERR_NONE on success.
 */

OGRErr OGRSpatialReference::SetLinearUnitsAndUpdateParameters(
    const char *pszName, double dfInMeters )

{
    double dfOldInMeters = GetLinearUnits();
    OGR_SRSNode *poPROJCS = GetAttrNode( "PROJCS" );

    if( dfInMeters == 0.0 )
        return OGRERR_FAILURE;

    if( dfInMeters == dfOldInMeters || poPROJCS == NULL )
        return SetLinearUnits( pszName, dfInMeters );

    for( int iChild = 0; iChild < poPROJCS->GetChildCount(); iChild++ )
    {
        const OGR_SRSNode     *poChild = poPROJCS->GetChild(iChild);
        
        if( EQUAL(poChild->GetValue(),"PARAMETER")
            && poChild->GetChildCount() > 1 )
        {
            char *pszParmName = CPLStrdup(poChild->GetChild(0)->GetValue());
            
            if( IsLinearParameter( pszParmName ) )
            {
                double dfOldValue = GetProjParm( pszParmName );

                SetProjParm( pszParmName, 
                             dfOldValue * dfOldInMeters / dfInMeters );
            }

            CPLFree( pszParmName );
        }
    }

    return SetLinearUnits( pszName, dfInMeters );
}

/************************************************************************/
/*                           SetLinearUnits()                           */
/************************************************************************/

/**
 * Set the linear units for the projection.
 *
 * This method creates a UNITS subnode with the specified values as a
 * child of the PROJCS or LOCAL_CS node. 
 *
 * This method does the same as the C function OSRSetLinearUnits(). 
 *
 * @param pszUnitsName the units name to be used.  Some preferred units
 * names can be found in ogr_srs_api.h such as SRS_UL_METER, SRS_UL_FOOT 
 * and SRS_UL_US_FOOT. 
 *
 * @param dfInMeters the value to multiple by a length in the indicated
 * units to transform to meters.  Some standard conversion factors can
 * be found in ogr_srs_api.h. 
 *
 * @return OGRERR_NONE on success.
 */

OGRErr OGRSpatialReference::SetLinearUnits( const char * pszUnitsName,
                                            double dfInMeters )

{
    OGR_SRSNode *poCS;
    OGR_SRSNode *poUnits;
    char        szValue[128];

    bNormInfoSet = FALSE;

    poCS = GetAttrNode( "PROJCS" );
    if( poCS == NULL )
        poCS = GetAttrNode( "LOCAL_CS" );

    if( poCS == NULL )
        return OGRERR_FAILURE;

    if( dfInMeters == (int) dfInMeters )
        sprintf( szValue, "%d", (int) dfInMeters );
    else
        //notdef: sprintf( szValue, "%.16g", dfInMeters );
        OGRPrintDouble( szValue, dfInMeters );

    if( poCS->FindChild( "UNIT" ) >= 0 )
    {
        poUnits = poCS->GetChild( poCS->FindChild( "UNIT" ) );
        poUnits->GetChild(0)->SetValue( pszUnitsName );
        poUnits->GetChild(1)->SetValue( szValue );
        if( poUnits->FindChild( "AUTHORITY" ) != -1 )
            poUnits->DestroyChild( poUnits->FindChild( "AUTHORITY" ) );
    }
    else
    {
        poUnits = new OGR_SRSNode( "UNIT" );
        poUnits->AddChild( new OGR_SRSNode( pszUnitsName ) );
        poUnits->AddChild( new OGR_SRSNode( szValue ) );
        
        poCS->AddChild( poUnits );
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                         OSRSetLinearUnits()                          */
/************************************************************************/

OGRErr OSRSetLinearUnits( OGRSpatialReferenceH hSRS, 
                          const char * pszUnits, double dfInMeters )

{
    return ((OGRSpatialReference *) hSRS)->SetLinearUnits( pszUnits, 
                                                           dfInMeters );
}

/************************************************************************/
/*                           GetLinearUnits()                           */
/************************************************************************/

/**
 * Fetch linear projection units. 
 *
 * If no units are available, a value of "Meters" and 1.0 will be assumed.
 * This method only checks directly under the PROJCS or LOCAL_CS node for 
 * units.
 *
 * This method does the same thing as the C function OSRGetLinearUnits()/
 *
 * @param ppszName a pointer to be updated with the pointer to the 
 * units name.  The returned value remains internal to the OGRSpatialReference
 * and shouldn't be freed, or modified.  It may be invalidated on the next
 * OGRSpatialReference call. 
 *
 * @return the value to multiply by linear distances to transform them to 
 * meters.
 */

double OGRSpatialReference::GetLinearUnits( char ** ppszName ) const

{
    const OGR_SRSNode *poCS = GetAttrNode( "PROJCS" );

    if( poCS == NULL )
        poCS = GetAttrNode( "LOCAL_CS" );

    if( ppszName != NULL )
        *ppszName = "unknown";
        
    if( poCS == NULL )
        return 1.0;

    for( int iChild = 0; iChild < poCS->GetChildCount(); iChild++ )
    {
        const OGR_SRSNode     *poChild = poCS->GetChild(iChild);
        
        if( EQUAL(poChild->GetValue(),"UNIT")
            && poChild->GetChildCount() >= 2 )
        {
            if( ppszName != NULL )
                *ppszName = (char *) poChild->GetChild(0)->GetValue();
            
            return atof( poChild->GetChild(1)->GetValue() );
        }
    }

    return 1.0;
}

/************************************************************************/
/*                         OSRGetLinearUnits()                          */
/************************************************************************/

double OSRGetLinearUnits( OGRSpatialReferenceH hSRS, char ** ppszName )
    
{
    return ((OGRSpatialReference *) hSRS)->GetLinearUnits( ppszName );
}

/************************************************************************/
/*                          GetPrimeMeridian()                          */
/************************************************************************/

/**
 * Fetch prime meridian info.
 *
 * Returns the offset of the prime meridian from greenwich in degrees,
 * and the prime meridian name (if requested).   If no PRIMEM value exists
 * in the coordinate system definition a value of "Greenwich" and an
 * offset of 0.0 is assumed.
 *
 * If the prime meridian name is returned, the pointer is to an internal
 * copy of the name. It should not be freed, altered or depended on after
 * the next OGR call.
 *
 * This method is the same as the C function OSRGetPrimeMeridian().
 *
 * @param ppszName return location for prime meridian name.  If NULL, name
 * is not returned.
 *
 * @return the offset to the GEOGCS prime meridian from greenwich in decimal
 * degrees.
 */

double OGRSpatialReference::GetPrimeMeridian( char **ppszName ) const 

{
    const OGR_SRSNode *poPRIMEM = GetAttrNode( "PRIMEM" );

    if( poPRIMEM != NULL && poPRIMEM->GetChildCount() >= 2 
        && atof(poPRIMEM->GetChild(1)->GetValue()) != 0.0 )
    {
        if( ppszName != NULL )
            *ppszName = (char *) poPRIMEM->GetChild(0)->GetValue();
        return atof(poPRIMEM->GetChild(1)->GetValue());
    }
    
    if( ppszName != NULL )
        *ppszName = SRS_PM_GREENWICH;

    return 0.0;
}

/************************************************************************/
/*                        OSRGetPrimeMeridian()                         */
/************************************************************************/

double OSRGetPrimeMeridian( OGRSpatialReferenceH hSRS, char **ppszName )

{
    return ((OGRSpatialReference *) hSRS)->GetPrimeMeridian( ppszName );
}

/************************************************************************/
/*                             SetGeogCS()                              */
/************************************************************************/

/**
 * Set geographic coordinate system. 
 *
 * This method is used to set the datum, ellipsoid, prime meridian and
 * angular units for a geographic coordinate system.  It can be used on it's
 * own to establish a geographic spatial reference, or applied to a 
 * projected coordinate system to establish the underlying geographic 
 * coordinate system.