ogrspatialreference.cpp

用于读取TAB、MIF、SHP文件的类

{
    return ((OGRSpatialReference *) hSRS)->Dereference();
}

/************************************************************************/
/*                         GetReferenceCount()                          */
/************************************************************************/

/**
 * \fn int OGRSpatialReference::GetReferenceCount() const;
 *
 * Fetch current reference count.
 *
 * @return the current reference count.
 */

/************************************************************************/
/*                              Release()                               */
/************************************************************************/

/**
 * Decrements the reference count by one, and destroy if zero.
 *
 * The method does the same thing as the C function OSRRelease(). 
 */

void OGRSpatialReference::Release()

{
    if( this && Dereference() == 0 )
        delete this;
}

/************************************************************************/
/*                             OSRRelease()                             */
/************************************************************************/

void OSRRelease( OGRSpatialReferenceH hSRS )

{
    ((OGRSpatialReference *) hSRS)->Release();
}

/************************************************************************/
/*                              SetRoot()                               */
/************************************************************************/

/**
 * Set the root SRS node.
 *
 * If the object has an existing tree of OGR_SRSNodes, they are destroyed
 * as part of assigning the new root.  Ownership of the passed OGR_SRSNode is
 * is assumed by the OGRSpatialReference.
 *
 * @param poNewRoot object to assign as root.
 */

void OGRSpatialReference::SetRoot( OGR_SRSNode * poNewRoot )

{
    if( poRoot != NULL )
        delete poRoot;

    poRoot = poNewRoot;
}

/************************************************************************/
/*                            GetAttrNode()                             */
/************************************************************************/

/**
 * Find named node in tree.
 *
 * This method does a pre-order traversal of the node tree searching for
 * a node with this exact value (case insensitive), and returns it.  Leaf
 * nodes are not considered, under the assumption that they are just
 * attribute value nodes.
 *
 * If a node appears more than once in the tree (such as UNIT for instance),
 * the first encountered will be returned.  Use GetNode() on a subtree to be
 * more specific. 
 *
 * @param pszNodePath the name of the node to search for.  May contain multiple
 * components such as "GEOGCS|UNITS".
 *
 * @return a pointer to the node found, or NULL if none.
 */

OGR_SRSNode *OGRSpatialReference::GetAttrNode( const char * pszNodePath )

{
    char        **papszPathTokens;
    OGR_SRSNode *poNode;

    papszPathTokens = CSLTokenizeStringComplex(pszNodePath, "|", TRUE, FALSE);

    if( CSLCount( papszPathTokens ) < 1 )
        return NULL;

    poNode = GetRoot();
    for( int i = 0; poNode != NULL && papszPathTokens[i] != NULL; i++ )
    {
        poNode = poNode->GetNode( papszPathTokens[i] );
    }

    CSLDestroy( papszPathTokens );

    return poNode;
}

const OGR_SRSNode *
OGRSpatialReference::GetAttrNode( const char * pszNodePath ) const

{
    OGR_SRSNode *poNode;

    poNode = ((OGRSpatialReference *) this)->GetAttrNode(pszNodePath);

    return poNode;
}

/************************************************************************/
/*                            GetAttrValue()                            */
/************************************************************************/

/**
 * Fetch indicated attribute of named node.
 *
 * This method uses GetAttrNode() to find the named node, and then extracts
 * the value of the indicated child.  Thus a call to GetAttrValue("UNIT",1)
 * would return the second child of the UNIT node, which is normally the
 * length of the linear unit in meters.
 *
 * This method does the same thing as the C function OSRGetAttrValue().
 *
 * @param pszNodeName the tree node to look for (case insensitive).
 * @param iAttr the child of the node to fetch (zero based).
 *
 * @return the requested value, or NULL if it fails for any reason. 
 */

const char *OGRSpatialReference::GetAttrValue( const char * pszNodeName,
                                               int iAttr ) const

{
    const OGR_SRSNode *poNode;

    poNode = GetAttrNode( pszNodeName );
    if( poNode == NULL )
        return NULL;

    if( iAttr < 0 || iAttr >= poNode->GetChildCount() )
        return NULL;

    return poNode->GetChild(iAttr)->GetValue();
}

/************************************************************************/
/*                          OSRGetAttrValue()                           */
/************************************************************************/

const char * CPL_STDCALL OSRGetAttrValue( OGRSpatialReferenceH hSRS,
                             const char * pszKey, int iChild )

{
    return ((OGRSpatialReference *) hSRS)->GetAttrValue( pszKey, iChild );
}

/************************************************************************/
/*                               Clone()                                */
/************************************************************************/

/**
 * Make a duplicate of this OGRSpatialReference.
 *
 * This method is the same as the C function OSRClone().
 *
 * @return a new SRS, which becomes the responsibility of the caller.
 */

OGRSpatialReference *OGRSpatialReference::Clone() const

{
    OGRSpatialReference *poNewRef;

    poNewRef = new OGRSpatialReference();

    if( poRoot != NULL )
        poNewRef->poRoot = poRoot->Clone();

    return poNewRef;
}

/************************************************************************/
/*                              OSRClone()                              */
/************************************************************************/

OGRSpatialReferenceH CPL_STDCALL OSRClone( OGRSpatialReferenceH hSRS )

{
    return (OGRSpatialReferenceH) ((OGRSpatialReference *) hSRS)->Clone();
}

/************************************************************************/
/*                         exportToPrettyWkt()                          */
/*                                                                      */
/*      Translate into a nicely formatted string for display to a       */
/*      person.                                                         */
/************************************************************************/

OGRErr OGRSpatialReference::exportToPrettyWkt( char ** ppszResult, 
                                               int bSimplify ) const

{
    if( poRoot == NULL )
    {
        *ppszResult = CPLStrdup("");
        return OGRERR_NONE;
    }

    if( bSimplify )
    {
        OGRSpatialReference *poSimpleClone = Clone();
        OGRErr eErr;

        poSimpleClone->GetRoot()->StripNodes( "AXIS" );
        poSimpleClone->GetRoot()->StripNodes( "AUTHORITY" );
        poSimpleClone->GetRoot()->StripNodes( "EXTENSION" );
        eErr = poSimpleClone->GetRoot()->exportToPrettyWkt( ppszResult, 1 );
        delete poSimpleClone;
        return eErr;
    }
    else
        return poRoot->exportToPrettyWkt( ppszResult, 1 );
}

/************************************************************************/
/*                        OSRExportToPrettyWkt()                        */
/************************************************************************/

OGRErr CPL_STDCALL OSRExportToPrettyWkt( OGRSpatialReferenceH hSRS, char ** ppszReturn,
                             int bSimplify)

{
    *ppszReturn = NULL;

    return ((OGRSpatialReference *) hSRS)->exportToPrettyWkt( ppszReturn,
                                                              bSimplify );
}

/************************************************************************/
/*                            exportToWkt()                             */
/************************************************************************/

/**
 * Convert this SRS into WKT format.
 *
 * Note that the returned WKT string should be freed with OGRFree() or
 * CPLFree() when no longer needed.  It is the responsibility of the caller.
 *
 * This method is the same as the C function OSRExportToWkt().
 *
 * @param ppszResult the resulting string is returned in this pointer.
 *
 * @return currently OGRERR_NONE is always returned, but the future it
 * is possible error conditions will develop. 
 */
 
OGRErr  OGRSpatialReference::exportToWkt( char ** ppszResult ) const

{
    if( poRoot == NULL )
    {
        *ppszResult = CPLStrdup("");
        return OGRERR_NONE;
    }
    else
    {
        return poRoot->exportToWkt(ppszResult);
    }
}

/************************************************************************/
/*                           OSRExportToWkt()                           */
/************************************************************************/

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

{
    *ppszReturn = NULL;

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

/************************************************************************/
/*                           importFromWkt()                            */
/************************************************************************/

/**
 * Import from WKT string.
 *
 * This method will wipe the existing SRS definition, and
 * reassign it based on the contents of the passed WKT string.  Only as
 * much of the input string as needed to construct this SRS is consumed from
 * the input string, and the input string pointer
 * is then updated to point to the remaining (unused) input.
 *
 * This method is the same as the C function OSRImportFromWkt().
 *
 * @param ppszInput Pointer to pointer to input.  The pointer is updated to
 * point to remaining unused input text.
 *
 * @return OGRERR_NONE if import succeeds, or OGRERR_CORRUPT_DATA if it
 * fails for any reason.
 */

OGRErr OGRSpatialReference::importFromWkt( char ** ppszInput )

{
    if( poRoot != NULL )
        delete poRoot;

    bNormInfoSet = FALSE;

    poRoot = new OGR_SRSNode();

    return poRoot->importFromWkt( ppszInput );
}

/************************************************************************/
/*                          OSRImportFromWkt()                          */
/************************************************************************/

OGRErr OSRImportFromWkt( OGRSpatialReferenceH hSRS, char **ppszInput )

{
    return ((OGRSpatialReference *) hSRS)->importFromWkt( ppszInput );
}

/************************************************************************/
/*                              SetNode()                               */
/************************************************************************/

/**
 * Set attribute value in spatial reference.
 *
 * Missing intermediate nodes in the path will be created if not already
 * in existance.  If the attribute has no children one will be created and
 * assigned the value otherwise the zeroth child will be assigned the value.
 *
 * This method does the same as the C function OSRSetAttrValue(). 
 *
 * @param pszNodePath full path to attribute to be set.  For instance
 * "PROJCS|GEOGCS|UNITS".
 * 
 * @param pszNewNodeValue value to be assigned to node, such as "meter". 
 * This may be NULL if you just want to force creation of the intermediate
 * path.
 *
 * @return OGRERR_NONE on success. 
 */

OGRErr OGRSpatialReference::SetNode( const char * pszNodePath,
                                     const char * pszNewNodeValue )

{
    char        **papszPathTokens;
    int         i;
    OGR_SRSNode *poNode;

    papszPathTokens = CSLTokenizeStringComplex(pszNodePath, "|", TRUE, FALSE);

    if( CSLCount( papszPathTokens ) < 1 )
        return OGRERR_FAILURE;

    if( GetRoot() == NULL || !EQUAL(papszPathTokens[0],GetRoot()->GetValue()) )
    {