ogrspatialreference.cpp

mitab,读取MapInfo的地图文件

/******************************************************************************
 * $Id: ogrspatialreference.cpp 11724 2007-07-05 15:53:06Z dron $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  The OGRSpatialReference class.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 1999,  Les Technologies SoftMap Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "ogr_spatialref.h"
#include "ogr_p.h"
#include "cpl_csv.h"

CPL_CVSID("$Id: ogrspatialreference.cpp 11724 2007-07-05 15:53:06Z dron $");

// The current opinion is that WKT longitudes like central meridian
// should be relative to greenwich, not the prime meridian in use. 
// Define the following if they should be relative to the prime meridian
// of then geogcs.
#undef WKT_LONGITUDE_RELATIVE_TO_PM

/************************************************************************/
/*                           OGRPrintDouble()                           */
/************************************************************************/

static void OGRPrintDouble( char * pszStrBuf, double dfValue )

{
    sprintf( pszStrBuf, "%.16g", dfValue );

    int nLen = strlen(pszStrBuf);

    // The following hack is intended to truncate some "precision" in cases
    // that appear to be roundoff error. 
    if( nLen > 15 
        && (strcmp(pszStrBuf+nLen-6,"999999") == 0
            || strcmp(pszStrBuf+nLen-6,"000001") == 0) )
    {
        sprintf( pszStrBuf, "%.15g", dfValue );
    }
}

/************************************************************************/
/*                        OGRSpatialReference()                         */
/************************************************************************/

/**
 * Constructor.
 *
 * This constructor takes an optional string argument which if passed
 * should be a WKT representation of an SRS.  Passing this is equivelent
 * to not passing it, and then calling importFromWkt() with the WKT string.
 *
 * Note that newly created objects are given a reference count of one. 
 *
 * The C function OSRNewSpatialReference() does the same thing as this
 * constructor. 
 *
 * @param pszWKT well known text definition to which the object should
 * be initialized, or NULL (the default). 
 */

OGRSpatialReference::OGRSpatialReference( const char * pszWKT )

{
    bNormInfoSet = FALSE;
    nRefCount = 1;
    poRoot = NULL;

    if( pszWKT != NULL )
        importFromWkt( (char **) &pszWKT );
}

/************************************************************************/
/*                       OSRNewSpatialReference()                       */
/************************************************************************/

OGRSpatialReferenceH CPL_STDCALL OSRNewSpatialReference( const char *pszWKT )

{
    OGRSpatialReference * poSRS;

    poSRS = new OGRSpatialReference();

    if( pszWKT != NULL && strlen(pszWKT) > 0 )
    {
        if( poSRS->importFromWkt( (char **) (&pszWKT) ) != OGRERR_NONE )
        {
            delete poSRS;
            poSRS = NULL;
        }
    }

    return poSRS;
}

/************************************************************************/
/*                        OGRSpatialReference()                         */
/*                                                                      */
/*      Simple copy constructor.  See also Clone().                     */
/************************************************************************/

OGRSpatialReference::OGRSpatialReference(const OGRSpatialReference &oOther)

{
    bNormInfoSet = FALSE;
    nRefCount = 1;
    poRoot = NULL;

    if( oOther.poRoot != NULL )
        poRoot = oOther.poRoot->Clone();
}

/************************************************************************/
/*                        ~OGRSpatialReference()                        */
/************************************************************************/

/**
 * OGRSpatialReference destructor. 
 *
 * The C function OSRDestroySpatialReference() does the same thing as this
 * method. 
 */

OGRSpatialReference::~OGRSpatialReference()

{
    if( poRoot != NULL )
        delete poRoot;
}

/************************************************************************/
/*                     OSRDestroySpatialReference()                     */
/************************************************************************/

void CPL_STDCALL OSRDestroySpatialReference( OGRSpatialReferenceH hSRS )

{
    delete ((OGRSpatialReference *) hSRS);
}

/************************************************************************/
/*                               Clear()                                */
/************************************************************************/

/**
 * Wipe current definition.
 *
 * Returns OGRSpatialReference to a state with no definition, as it 
 * exists when first created.  It does not affect reference counts.
 */

void OGRSpatialReference::Clear()

{
    if( poRoot )
        delete poRoot;

    poRoot = NULL;
}

/************************************************************************/
/*                             operator=()                              */
/************************************************************************/

OGRSpatialReference &
OGRSpatialReference::operator=(const OGRSpatialReference &oSource)

{
    if( poRoot != NULL )
    {
        delete poRoot;
        poRoot = NULL;
    }
    
    if( oSource.poRoot != NULL )
        poRoot = oSource.poRoot->Clone();

    return *this;
}

/************************************************************************/
/*                             Reference()                              */
/************************************************************************/

/**
 * Increments the reference count by one.
 *
 * The reference count is used keep track of the number of OGRGeometry objects
 * referencing this SRS.
 *
 * The method does the same thing as the C function OSRReference(). 
 *
 * @return the updated reference count.
 */

int OGRSpatialReference::Reference()

{
    return ++nRefCount;
}

/************************************************************************/
/*                            OSRReference()                            */
/************************************************************************/

int OSRReference( OGRSpatialReferenceH hSRS )

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

/************************************************************************/
/*                            Dereference()                             */
/************************************************************************/

/**
 * Decrements the reference count by one.
 *
 * The method does the same thing as the C function OSRDereference(). 
 *
 * @return the updated reference count.
 */

int OGRSpatialReference::Dereference()

{
    return --nRefCount;
}

/************************************************************************/
/*                           OSRDereference()                           */
/************************************************************************/

int OSRDereference( OGRSpatialReferenceH hSRS )

{
    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;
}