ogrgeometry.cpp

用于读取TAB、MIF、SHP文件的类

 *
 * @return the newly created geometry, or NULL if an error occurs. 
 */

OGRGeometry *OGRGeometry::Buffer( double dfDist, int nQuadSegs ) const

{
#ifndef HAVE_GEOS

    CPLError( CE_Failure, CPLE_NotSupported, 
              "GEOS support not enabled." );
    return NULL;

#else

    GEOSGeom hGeosGeom = NULL;
    GEOSGeom hGeosProduct = NULL;
    OGRGeometry *poOGRProduct = NULL;

    hGeosGeom = exportToGEOS();
    if( hGeosGeom != NULL )
    {
        hGeosProduct = GEOSBuffer( hGeosGeom, dfDist, nQuadSegs );
        GEOSGeom_destroy( hGeosGeom );

        if( hGeosProduct != NULL )
        {
            poOGRProduct = OGRGeometryFactory::createFromGEOS(hGeosProduct);
            GEOSGeom_destroy( hGeosProduct );
        }
    }

    return poOGRProduct;

#endif /* HAVE_GEOS */
}

/************************************************************************/
/*                            OGR_G_Buffer()                            */
/************************************************************************/

OGRGeometryH OGR_G_Buffer( OGRGeometryH hTarget, double dfDist, int nQuadSegs )

{
    return (OGRGeometryH) ((OGRGeometry *) hTarget)->Buffer( dfDist, nQuadSegs );
}

/************************************************************************/
/*                            Intersection()                            */
/************************************************************************/

/**
 * Compute intersection.
 *
 * Generates a new geometry which is the region of intersection of the
 * two geometries operated on.  The Intersect() method can be used to test if
 * two geometries intersect. 
 *
 * This method is the same as the C function OGR_G_Intersection().
 *
 * This method is built on the GEOS library, check it for the definition
 * of the geometry operation.
 * If OGR is built without the GEOS library, this method will always fail, 
 * issuing a CPLE_NotSupported error. 
 *
 * @param poOtherGeom the other geometry intersected with "this" geometry.
 *
 * @return a new geometry representing the intersection or NULL if there is
 * no intersection or an error occurs.
 */

OGRGeometry *OGRGeometry::Intersection( const OGRGeometry *poOtherGeom ) const

{
#ifndef HAVE_GEOS

    CPLError( CE_Failure, CPLE_NotSupported, 
              "GEOS support not enabled." );
    return NULL;

#else

    GEOSGeom hThisGeosGeom = NULL;
    GEOSGeom hOtherGeosGeom = NULL;
    GEOSGeom hGeosProduct = NULL;
    OGRGeometry *poOGRProduct = NULL;

    hThisGeosGeom = exportToGEOS();
    hOtherGeosGeom = poOtherGeom->exportToGEOS();
    if( hThisGeosGeom != NULL && hOtherGeosGeom != NULL )
    {
        hGeosProduct = GEOSIntersection( hThisGeosGeom, hOtherGeosGeom );
        GEOSGeom_destroy( hThisGeosGeom );
        GEOSGeom_destroy( hOtherGeosGeom );

        if( hGeosProduct != NULL )
        {
            poOGRProduct = OGRGeometryFactory::createFromGEOS(hGeosProduct);
            GEOSGeom_destroy( hGeosProduct );
        }
    }

    return poOGRProduct;

#endif /* HAVE_GEOS */
}

/************************************************************************/
/*                         OGR_G_Intersection()                         */
/************************************************************************/

OGRGeometryH OGR_G_Intersection( OGRGeometryH hThis, OGRGeometryH hOther )

{
    return (OGRGeometryH) 
        ((OGRGeometry *) hThis)->Intersection( (OGRGeometry *) hOther );
}

/************************************************************************/
/*                               Union()                                */
/************************************************************************/

/**
 * Compute union.
 *
 * Generates a new geometry which is the region of union of the
 * two geometries operated on.  
 *
 * This method is the same as the C function OGR_G_Union().
 *
 * This method is built on the GEOS library, check it for the definition
 * of the geometry operation.
 * If OGR is built without the GEOS library, this method will always fail, 
 * issuing a CPLE_NotSupported error. 
 *
 * @param poOtherGeom the other geometry unioned with "this" geometry.
 *
 * @return a new geometry representing the union or NULL if an error occurs.
 */

OGRGeometry *OGRGeometry::Union( const OGRGeometry *poOtherGeom ) const

{
#ifndef HAVE_GEOS

    CPLError( CE_Failure, CPLE_NotSupported, 
              "GEOS support not enabled." );
    return NULL;

#else

    GEOSGeom hThisGeosGeom = NULL;
    GEOSGeom hOtherGeosGeom = NULL;
    GEOSGeom hGeosProduct = NULL;
    OGRGeometry *poOGRProduct = NULL;

    hThisGeosGeom = exportToGEOS();
    hOtherGeosGeom = poOtherGeom->exportToGEOS();
    if( hThisGeosGeom != NULL && hOtherGeosGeom != NULL )
    {
        hGeosProduct = GEOSUnion( hThisGeosGeom, hOtherGeosGeom );
        GEOSGeom_destroy( hThisGeosGeom );
        GEOSGeom_destroy( hOtherGeosGeom );

        if( hGeosProduct != NULL )
        {
            poOGRProduct = OGRGeometryFactory::createFromGEOS(hGeosProduct);
            GEOSGeom_destroy( hGeosProduct );
        }
    }

    return poOGRProduct;

#endif /* HAVE_GEOS */
}

/************************************************************************/
/*                            OGR_G_Union()                             */
/************************************************************************/

OGRGeometryH OGR_G_Union( OGRGeometryH hThis, OGRGeometryH hOther )

{
    return (OGRGeometryH) 
        ((OGRGeometry *) hThis)->Union( (OGRGeometry *) hOther );
}

/************************************************************************/
/*                             Difference()                             */
/************************************************************************/

/**
 * Compute difference.
 *
 * Generates a new geometry which is the region of this geometry with the
 * region of the second geometry removed. 
 *
 * This method is the same as the C function OGR_G_Difference().
 *
 * This method is built on the GEOS library, check it for the definition
 * of the geometry operation.
 * If OGR is built without the GEOS library, this method will always fail, 
 * issuing a CPLE_NotSupported error. 
 *
 * @param poOtherGeom the other geometry removed from "this" geometry.
 *
 * @return a new geometry representing the difference or NULL if the 
 * difference is empty or an error occurs.
 */

OGRGeometry *OGRGeometry::Difference( const OGRGeometry *poOtherGeom ) const

{
#ifndef HAVE_GEOS

    CPLError( CE_Failure, CPLE_NotSupported, 
              "GEOS support not enabled." );
    return NULL;

#else
    
    GEOSGeom hThisGeosGeom = NULL;
    GEOSGeom hOtherGeosGeom = NULL;
    GEOSGeom hGeosProduct = NULL;
    OGRGeometry *poOGRProduct = NULL;

    hThisGeosGeom = exportToGEOS();
    hOtherGeosGeom = poOtherGeom->exportToGEOS();
    if( hThisGeosGeom != NULL && hOtherGeosGeom != NULL )
    {
        hGeosProduct = GEOSDifference( hThisGeosGeom, hOtherGeosGeom );
        GEOSGeom_destroy( hThisGeosGeom );
        GEOSGeom_destroy( hOtherGeosGeom );

        if( hGeosProduct != NULL )
        {
            poOGRProduct = OGRGeometryFactory::createFromGEOS(hGeosProduct);
            GEOSGeom_destroy( hGeosProduct );
        }
    }

    return poOGRProduct;

#endif /* HAVE_GEOS */
}

/************************************************************************/
/*                          OGR_G_Difference()                          */
/************************************************************************/

OGRGeometryH OGR_G_Difference( OGRGeometryH hThis, OGRGeometryH hOther )

{
    return (OGRGeometryH) 
        ((OGRGeometry *) hThis)->Difference( (OGRGeometry *) hOther );
}

/************************************************************************/
/*                        SymmetricDifference()                         */
/************************************************************************/

/**
 * Compute symmetric difference.
 *
 * Generates a new geometry which is the symmetric difference of this
 * geometry and the second geometry passed into the method.
 *
 * This method is the same as the C function OGR_G_SymmetricDifference().
 *
 * This method is built on the GEOS library, check it for the definition
 * of the geometry operation.
 * If OGR is built without the GEOS library, this method will always fail, 
 * issuing a CPLE_NotSupported error. 
 *
 * @param poOtherGeom the other geometry.
 *
 * @return a new geometry representing the symmetric difference or NULL if the 
 * difference is empty or an error occurs.
 */

OGRGeometry *
OGRGeometry::SymmetricDifference( const OGRGeometry *poOtherGeom ) const

{
#ifndef HAVE_GEOS

    CPLError( CE_Failure, CPLE_NotSupported, 
              "GEOS support not enabled." );
    return NULL;

#else

    GEOSGeom hThisGeosGeom = NULL;
    GEOSGeom hOtherGeosGeom = NULL;
    GEOSGeom hGeosProduct = NULL;
    OGRGeometry *poOGRProduct = NULL;

    hThisGeosGeom = exportToGEOS();
    hOtherGeosGeom = poOtherGeom->exportToGEOS();
    if( hThisGeosGeom != NULL && hOtherGeosGeom != NULL )
    {
        hGeosProduct = GEOSSymDifference( hThisGeosGeom, hOtherGeosGeom );
        GEOSGeom_destroy( hThisGeosGeom );
        GEOSGeom_destroy( hOtherGeosGeom );

        if( hGeosProduct != NULL )
        {
            poOGRProduct = OGRGeometryFactory::createFromGEOS(hGeosProduct);
            GEOSGeom_destroy( hGeosProduct );
        }
    }

    return poOGRProduct;

#endif /* HAVE_GEOS */
}

/************************************************************************/
/*                          OGR_G_Difference()                          */
/************************************************************************/

OGRGeometryH OGR_G_SymmetricDifference( OGRGeometryH hThis, OGRGeometryH hOther )

{
    return (OGRGeometryH) 
        ((OGRGeometry *) hThis)->SymmetricDifference( (OGRGeometry *) hOther );
}

/************************************************************************/
/*                              Disjoint()                              */
/************************************************************************/

/**
 * Test for disjointness.
 *
 * Tests if this geometry and the other passed into the method are disjoint. 
 *
 * This method is the same as the C function OGR_G_Disjoint().
 *
 * This method is built on the GEOS library, check it for the definition
 * of the geometry operation.
 * If OGR is built without the GEOS library, this method will always fail, 
 * issuing a CPLE_NotSupported error. 
 *
 * @param poOtherGeom the geometry to compare to this geometry.
 *
 * @return TRUE if they are disjoint, otherwise FALSE.  
 */

OGRBoolean
OGRGeometry::Disjoint( const OGRGeometry *poOtherGeom ) const

{
#ifndef HAVE_GEOS

    CPLError( CE_Failure, CPLE_NotSupported, 
              "GEOS support not enabled." );
    return FALSE;

#else

    GEOSGeom hThisGeosGeom = NULL;
    GEOSGeom hOtherGeosGeom = NULL;
    OGRBoolean bResult = FALSE;

    hThisGeosGeom = exportToGEOS();
    hOtherGeosGeom = poOtherGeom->exportToGEOS();
    if( hThisGeosGeom != NULL && hOtherGeosGeom != NULL )
    {
        bResult = GEOSDisjoint( hThisGeosGeom, hOtherGeosGeom );
        GEOSGeom_destroy( hThisGeosGeom );
        GEOSGeom_destroy( hOtherGeosGeom );
    }

    return bResult;

#endif /* HAVE_GEOS */
}

/************************************************************************/
/*                           OGR_G_Disjoint()                           */
/************************************************************************/

int OGR_G_Disjoint( OGRGeometryH hThis, OGRGeometryH hOther )

{
    return ((OGRGeometry *) hThis)->Disjoint( (OGRGeometry *) hOther );
}

/************************************************************************/
/*                              Touches()                               */
/************************************************************************/

/**
 * Test for touching.
 *
 * Tests if this geometry and the other passed into the method are touching.
 *
 * This method is the same as the C function OGR_G_Touches().
 *
 * This method is built on the GEOS library, check it for the definition
 * of the geometry operation.
 * If OGR is built without the GEOS library, this method will always fail, 
 * issuing a CPLE_NotSupported error. 
 *
 * @param poOtherGeom the geometry to compare to this geometry.
 *
 * @return TRUE if they are touchin