ogr_srs_xml.cpp

用于读取TAB、MIF、SHP文件的类

/* -------------------------------------------------------------------- */
/*      Transverse Mercator                                             */
/* -------------------------------------------------------------------- */
    if( EQUAL(pszProjection,SRS_PT_TRANSVERSE_MERCATOR) )
    {
        AddValueIDWithURN( psConv, "gml:usesMethod", "EPSG", "method", 
                           9807 );

        addProjArg( poSRS, psConv, "Angular", 0.0,
                    8801, SRS_PP_LATITUDE_OF_ORIGIN );
        addProjArg( poSRS, psConv, "Angular", 0.0,
                    8802, SRS_PP_CENTRAL_MERIDIAN );
        addProjArg( poSRS, psConv, "Unitless", 1.0,
                    8805, SRS_PP_SCALE_FACTOR );
        addProjArg( poSRS, psConv, "Linear", 0.0,
                    8806, SRS_PP_FALSE_EASTING );
        addProjArg( poSRS, psConv, "Linear", 0.0,
                    8807, SRS_PP_FALSE_NORTHING );
    }

/* -------------------------------------------------------------------- */
/*      Lambert Conformal Conic                                         */
/* -------------------------------------------------------------------- */
    else if( EQUAL(pszProjection, SRS_PT_LAMBERT_CONFORMAL_CONIC_1SP) )
    {
        AddValueIDWithURN( psConv, "gml:usesMethod", "EPSG", "method", 
                           9801 );

        addProjArg( poSRS, psConv, "Angular", 0.0,
                    8801, SRS_PP_LATITUDE_OF_ORIGIN );
        addProjArg( poSRS, psConv, "Angular", 0.0,
                    8802, SRS_PP_CENTRAL_MERIDIAN );
        addProjArg( poSRS, psConv, "Unitless", 1.0,
                    8805, SRS_PP_SCALE_FACTOR );
        addProjArg( poSRS, psConv, "Linear", 0.0,
                    8806, SRS_PP_FALSE_EASTING );
        addProjArg( poSRS, psConv, "Linear", 0.0,
                    8807, SRS_PP_FALSE_NORTHING );
    }

/* -------------------------------------------------------------------- */
/*      Define the cartesian coordinate system.                         */
/* -------------------------------------------------------------------- */
    CPLXMLNode  *psCCS;

    psCCS = 
        CPLCreateXMLNode( 
            CPLCreateXMLNode( psCRS_XML, CXT_Element, "gml:usesCartesianCS" ),
            CXT_Element, "gml:CartesianCS" );

    addGMLId( psCCS );

    CPLCreateXMLElementAndValue( psCCS, "gml:csName", "Cartesian" );
    addAuthorityIDBlock( psCCS, "gml:csID", "EPSG", "cs", 4400 );
    addAxis( psCCS, "E", NULL );
    addAxis( psCCS, "N", NULL );

    return psCRS_XML;
}

/************************************************************************/
/*                            exportToXML()                             */
/************************************************************************/

OGRErr OGRSpatialReference::exportToXML( char **ppszRawXML, 
                                         const char * /*pszDialect*/ ) const

{
    CPLXMLNode *psXMLTree = NULL;

    if( IsGeographic() )
    {
        psXMLTree = exportGeogCSToXML( this );
    }
    else if( IsProjected() )
    {
        psXMLTree = exportProjCSToXML( this );
    }
    else
        return OGRERR_UNSUPPORTED_SRS;

    *ppszRawXML = CPLSerializeXMLTree( psXMLTree );

    return OGRERR_NONE;
}

/************************************************************************/
/*                           OSRExportToXML()                           */
/************************************************************************/

OGRErr OSRExportToXML( OGRSpatialReferenceH hSRS, char **ppszRawXML, 
                       const char *pszDialect )

{
    return ((OGRSpatialReference *) hSRS)->exportToXML( ppszRawXML, 
                                                        pszDialect );
}

#ifdef notdef
/************************************************************************/
/*                           importXMLUnits()                           */
/************************************************************************/

static void importXMLUnits( CPLXMLNode *psSrcXML, const char *pszClass,
                            OGRSpatialReference *poSRS, const char *pszTarget)

{
    const char *pszUnitName, *pszUnitsPer;
    OGR_SRSNode *poNode = poSRS->GetAttrNode( pszTarget );
    OGR_SRSNode *poUnits;

    CPLAssert( EQUAL(pszClass,"AngularUnit") 
               || EQUAL(pszClass,"LinearUnit") );
        
    psSrcXML = CPLGetXMLNode( psSrcXML, pszClass );
    if( psSrcXML == NULL )
        goto DefaultTarget;

    pszUnitName = CPLGetXMLValue( psSrcXML, "NameSet.name", "unnamed" );
    if( EQUAL(pszClass,"AngularUnit") )
        pszUnitsPer = CPLGetXMLValue( psSrcXML, "radiansPerUnit", NULL );
    else
        pszUnitsPer = CPLGetXMLValue( psSrcXML, "metresPerUnit", NULL );
    
    if( pszUnitsPer == NULL )
    {
        CPLDebug( "OGR_SRS_XML", 
                  "Missing PerUnit value for %s.", 
                  pszClass );
        goto DefaultTarget;
    }
    
    if( poNode == NULL )
    {
        CPLDebug( "OGR_SRS_XML", "Can't find %s in importXMLUnits.", 
                  pszTarget );
        goto DefaultTarget;
    }

    if( poNode->FindChild("UNIT") != -1 )
    {
        poUnits = poNode->GetChild( poNode->FindChild( "UNIT" ) );
        poUnits->GetChild(0)->SetValue( pszUnitName );
        poUnits->GetChild(1)->SetValue( pszUnitsPer );
    }
    else
    {
        poUnits = new OGR_SRSNode( "UNIT" );
        poUnits->AddChild( new OGR_SRSNode( pszUnitName ) );
        poUnits->AddChild( new OGR_SRSNode( pszUnitsPer ) );
        
        poNode->AddChild( poUnits );
    }
    return;

  DefaultTarget:
    poUnits = new OGR_SRSNode( "UNIT" );
    if( EQUAL(pszClass,"AngularUnit") )
    {
        poUnits->AddChild( new OGR_SRSNode( SRS_UA_DEGREE ) );
        poUnits->AddChild( new OGR_SRSNode( SRS_UA_DEGREE_CONV ) );
    }
    else
    {
        poUnits->AddChild( new OGR_SRSNode( SRS_UL_METER ) );
        poUnits->AddChild( new OGR_SRSNode( "1.0" ) );
    }

    poNode->AddChild( poUnits );
}
#endif

/************************************************************************/
/*                         importXMLAuthority()                         */
/************************************************************************/

static void importXMLAuthority( CPLXMLNode *psSrcXML, 
                                OGRSpatialReference *poSRS, 
                                const char *pszSourceKey,
                                const char *pszTargetKey )

{
    CPLXMLNode *psIDNode = CPLGetXMLNode( psSrcXML, pszSourceKey );
    CPLXMLNode *psNameNode = CPLGetXMLNode( psIDNode, "name" );
    CPLXMLNode *psCodeSpace = CPLGetXMLNode( psNameNode, "codeSpace" );
    char *pszAuthority, *pszCode, *pszURN;
    int nCode = 0;

    if( psIDNode == NULL || psNameNode == NULL || psCodeSpace == NULL )
        return;

    pszURN = CPLStrdup(CPLGetXMLValue( psCodeSpace, "", "" ));
    if( !parseURN( pszURN, NULL, &pszAuthority, &pszCode ) )
    {
        CPLFree( pszURN );
        return;
    }

    if( strlen(pszCode) == 0 )
        pszCode = (char *) CPLGetXMLValue( psNameNode, "", "" );

    if( pszCode != NULL )
        nCode = atoi(pszCode);

    if( nCode != 0 )
        poSRS->SetAuthority( pszTargetKey, pszAuthority, nCode );

    CPLFree( pszURN );
}

/************************************************************************/
/*                           ParseOGCDefURN()                           */
/*                                                                      */
/*      Parse out fields from a URN of the form:                        */
/*        urn:ogc:def:parameter:EPSG:6.3:9707                           */
/************************************************************************/

static int ParseOGCDefURN( const char *pszURN, 
                           CPLString *poObjectType,
                           CPLString *poAuthority,
                           CPLString *poVersion, 
                           CPLString *poValue )

{
    if( poObjectType != NULL )
        *poObjectType = "";

    if( poAuthority != NULL )
        *poAuthority = "";

    if( poVersion != NULL )
        *poVersion = "";

    if( poValue != NULL )
        *poValue = "";

    if( pszURN == NULL || !EQUALN(pszURN,"urn:ogc:def:",12) )
        return FALSE;

    char **papszTokens = CSLTokenizeStringComplex( pszURN + 12, ":", 
                                                   FALSE, TRUE );

    if( CSLCount(papszTokens) != 4 )
    {
        CSLDestroy( papszTokens );
        return FALSE;
    }

    if( poObjectType != NULL )
        *poObjectType = papszTokens[0];

    if( poAuthority != NULL )
        *poAuthority = papszTokens[1];

    if( poVersion != NULL )
        *poVersion = papszTokens[2];

    if( poValue != NULL )
        *poValue = papszTokens[3];

    CSLDestroy( papszTokens );
    return TRUE;
}

/************************************************************************/
/*                       getEPSGObjectCodeValue()                       */
/*                                                                      */
/*      Fetch a code value from the indicated node.  Should work on     */
/*      something of the form <elem xlink:href="urn:...:n" /> or        */
/*      something of the form <elem xlink:href="urn:...:">n</a>.        */
/************************************************************************/

static int getEPSGObjectCodeValue( CPLXMLNode *psNode, 
                                   const char *pszEPSGObjectType, /*"method" */
                                   int nDefault )

{
    if( psNode == NULL )
        return nDefault;
    
    CPLString osObjectType, osAuthority, osValue;
    
    if( !ParseOGCDefURN( CPLGetXMLValue( psNode, "href", NULL ),
                         &osObjectType, &osAuthority, NULL, &osValue ) )
        return nDefault;

    if( !EQUAL(osAuthority,"EPSG") 
        || !EQUAL(osObjectType, pszEPSGObjectType) )
        return nDefault;

    if( strlen(osValue) > 0 )
        return atoi(osValue);

    const char *pszValue = CPLGetXMLValue( psNode, "", NULL);
    if( pszValue != NULL )
        return atoi(pszValue);
    else
        return nDefault;
}

/************************************************************************/
/*                         getProjectionParm()                          */
/************************************************************************/

static double getProjectionParm( CPLXMLNode *psRootNode, 
                                 int nParameterCode, 
                                 const char * /*pszMeasureType */, 
                                 double dfDefault )

{
    CPLXMLNode *psUsesParameter;

    for( psUsesParameter = psRootNode->psChild; 
         psUsesParameter != NULL;
         psUsesParameter = psUsesParameter->psNext )
    {
        if( psUsesParameter->eType != CXT_Element )
            continue;

        if( !EQUAL(psUsesParameter->pszValue,"usesParameterValue") 
            && !EQUAL(psUsesParameter->pszValue,"usesValue") )
            continue;

        if( getEPSGObjectCodeValue( CPLGetXMLNode(psUsesParameter,
                                                  "valueOfParameter"),
                                    "parameter", 0 ) == nParameterCode )
        {
            const char *pszValue = CPLGetXMLValue( psUsesParameter, "value", 
                                                   NULL );