ogrgeometry.cpp

在linux环境下

/******************************************************************************
 * $Id: ogrgeometry.cpp,v 1.19 2003/06/10 14:51:07 warmerda Exp $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements a few base methods on OGRGeometry.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 1999, Frank Warmerdam
 *
 * 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.
 ******************************************************************************
 *
 * $Log: ogrgeometry.cpp,v $
 * Revision 1.19  2003/06/10 14:51:07  warmerda
 * Allow Intersects() test against NULL geometry
 *
 * Revision 1.18  2003/04/03 23:39:11  danmo
 * Small updates to C API docs (Normand S.)
 *
 * Revision 1.17  2003/03/31 15:55:42  danmo
 * Added C API function docs
 *
 * Revision 1.16  2003/03/06 20:59:41  warmerda
 * Added exportToGML() implementation.
 *
 * Revision 1.15  2003/02/08 00:37:15  warmerda
 * try to improve documentation
 *
 * Revision 1.14  2002/10/24 16:46:33  warmerda
 * added docs and C implementation for Equal and FlattenTo2D
 *
 * Revision 1.13  2002/09/26 18:12:38  warmerda
 * added C support
 *
 * Revision 1.12  2002/05/03 14:16:23  warmerda
 * improve 3D geometry names
 *
 * Revision 1.11  2001/11/01 17:20:33  warmerda
 * added DISABLE_OGRGEOM_TRANSFORM macro
 *
 * Revision 1.10  2001/09/21 16:24:20  warmerda
 * added transform() and transformTo() methods
 *
 * Revision 1.9  2001/07/18 05:03:05  warmerda
 * added CPL_CVSID
 *
 * Revision 1.8  2001/02/06 14:14:09  warmerda
 * fixed up documentation
 *
 * Revision 1.7  2000/03/14 21:38:17  warmerda
 * added method to translate geometrytype to name
 *
 * Revision 1.6  1999/11/18 19:02:19  warmerda
 * expanded tabs
 *
 * Revision 1.5  1999/07/06 21:36:47  warmerda
 * tenatively added getEnvelope() and Intersect()
 *
 * Revision 1.4  1999/06/25 20:44:43  warmerda
 * implemented assignSpatialReference, carry properly
 *
 * Revision 1.3  1999/05/31 20:42:28  warmerda
 * added empty method
 *
 * Revision 1.2  1999/05/31 11:05:08  warmerda
 * added some documentation
 *
 * Revision 1.1  1999/05/20 14:35:00  warmerda
 * New
 *
 */

#include "ogr_geometry.h"
#include "ogr_api.h"
#include "ogr_p.h"
#include <assert.h>

CPL_CVSID("$Id: ogrgeometry.cpp,v 1.19 2003/06/10 14:51:07 warmerda Exp $");

/************************************************************************/
/*                            OGRGeometry()                             */
/************************************************************************/

OGRGeometry::OGRGeometry()

{
    poSRS = NULL;
}

/************************************************************************/
/*                            ~OGRGeometry()                            */
/************************************************************************/

OGRGeometry::~OGRGeometry()

{
    if( poSRS != NULL )
    {
        poSRS->Dereference();
    }
}


/************************************************************************/
/*                            dumpReadable()                            */
/************************************************************************/

/**
 * Dump geometry in well known text format to indicated output file.
 *
 * This method is the same as the C function OGR_G_DumpReadable().
 *
 * @param fp the text file to write the geometry to.
 * @param pszPrefix the prefix to put on each line of output.
 */

void OGRGeometry::dumpReadable( FILE * fp, const char * pszPrefix )

{
    char        *pszWkt = NULL;
    
    if( pszPrefix == NULL )
        pszPrefix = "";

    if( fp == NULL )
        fp = stdout;

    if( exportToWkt( &pszWkt ) == OGRERR_NONE )
    {
        fprintf( fp, "%s%s\n", pszPrefix, pszWkt );
        CPLFree( pszWkt );
    }
}

/************************************************************************/
/*                         OGR_G_DumpReadable()                         */
/************************************************************************/
/**
 * Dump geometry in well known text format to indicated output file.
 *
 * This method is the same as the CPP method OGRGeometry::dumpReadable.
 *
 * @param hGeom handle on the geometry to dump.
 * @param fp the text file to write the geometry to.
 * @param pszPrefix the prefix to put on each line of output.
 */

void OGR_G_DumpReadable( OGRGeometryH hGeom, FILE *fp, const char *pszPrefix )

{
    ((OGRGeometry *) hGeom)->dumpReadable( fp, pszPrefix );
}

/************************************************************************/
/*                       assignSpatialReference()                       */
/************************************************************************/

/**
 * \fn void OGRGeometry::assignSpatialReference( OGRSpatialReference * poSR );
 *
 * Assign spatial reference to this object.  Any existing spatial reference
 * is replaced, but under no circumstances does this result in the object
 * being reprojected.  It is just changing the interpretation of the existing
 * geometry.  Note that assigning a spatial reference increments the
 * reference count on the OGRSpatialReference, but does not copy it. 
 *
 * This is similar to the SFCOM IGeometry::put_SpatialReference() method.
 *
 * This method is the same as the C function OGR_G_AssignSpatialReference().
 *
 * @param poSR new spatial reference system to apply.
 */

void OGRGeometry::assignSpatialReference( OGRSpatialReference * poSR )

{
    if( poSRS != NULL )
        poSRS->Dereference();

    poSRS = poSR;
    if( poSRS != NULL )
        poSRS->Reference();
}

/************************************************************************/
/*                    OGR_G_AssignSpatialReference()                    */
/************************************************************************/
/**
 * Assign spatial reference to this object.  Any existing spatial reference
 * is replaced, but under no circumstances does this result in the object
 * being reprojected.  It is just changing the interpretation of the existing
 * geometry.  Note that assigning a spatial reference increments the
 * reference count on the OGRSpatialReference, but does not copy it. 
 *
 * This is similar to the SFCOM IGeometry::put_SpatialReference() method.
 *
 * This function is the same as the CPP method 
 * OGRGeometry::assignSpatialReference.
 *
 * @param hGeom handle on the geometry to apply the new spatial reference 
 * system.
 * @param hSRS handle on the  new spatial reference system to apply.
 */

void OGR_G_AssignSpatialReference( OGRGeometryH hGeom, 
                                   OGRSpatialReferenceH hSRS )

{
    ((OGRGeometry *) hGeom)->assignSpatialReference( (OGRSpatialReference *)
                                                     hSRS );
}

/************************************************************************/
/*                             Intersect()                              */
/************************************************************************/

/**
 * Do these features intersect?
 *
 * Currently this is not implemented in a rigerous fashion, and generally
 * just tests whether the envelopes of the two features intersect.  Eventually
 * this will be made rigerous.  
 *
 * The poOtherGeom argument may be safely NULL, but in this case the method
 * will always return FALSE.  
 *
 * This method is the same as the C function OGR_G_Intersect().
 *
 * @param poOtherGeom the other geometry to test against.  
 *
 * @return TRUE if the geometries intersect, otherwise FALSE.
 */

OGRBoolean OGRGeometry::Intersect( OGRGeometry *poOtherGeom )

{
    OGREnvelope         oEnv1, oEnv2;

    if( this == NULL || poOtherGeom == NULL )
        return FALSE;

    this->getEnvelope( &oEnv1 );
    poOtherGeom->getEnvelope( &oEnv2 );

    if( oEnv1.MaxX < oEnv2.MinX
        || oEnv1.MaxY < oEnv2.MinY
        || oEnv2.MaxX < oEnv1.MinX
        || oEnv2.MaxY < oEnv1.MinY )
        return FALSE;
    else
        return TRUE;
}

/************************************************************************/
/*                          OGR_G_Intersect()                           */
/************************************************************************/
/**
 * Do these features intersect?
 *
 * Currently this is not implemented in a rigerous fashion, and generally
 * just tests whether the envelopes of the two features intersect.  Eventually
 * this will be made rigerous.
 *
 * This function is the same as the CPP method OGRGeometry::Intersect.
 *
 * @param hGeom handle on the first geometry.
 * @param hOtherGeom handle on the other geometry to test against.
 *
 * @return TRUE if the geometries intersect, otherwise FALSE.
 */

int OGR_G_Intersect( OGRGeometryH hGeom, OGRGeometryH hOtherGeom )

{
    return ((OGRGeometry *) hGeom)->Intersect( (OGRGeometry *) hOtherGeom );
}

/************************************************************************/
/*                            transformTo()                             */
/************************************************************************/

/**
 * Transform geometry to new spatial reference system.
 *
 * This method will transform the coordinates of a geometry from
 * their current spatial reference system to a new target spatial
 * reference system.  Normally this means reprojecting the vectors,
 * but it could include datum shifts, and changes of units. 
 *
 * This method will only work if the geometry already has an assigned
 * spatial reference system, and if it is transformable to the target
 * coordinate system.
 *
 * Because this method requires internal creation and initialization of an
 * OGRCoordinateTransformation object it is significantly more expensive to
 * use this method to transform many geometries than it is to create the
 * OGRCoordinateTransformation in advance, and call transform() with that
 * transformation.  This method exists primarily for convenience when only
 * transforming a single geometry.
 *
 * This method is the same as the C function OGR_G_TransformTo().
 * 
 * @param poSR spatial reference system to transform to.
 *
 * @return OGRERR_NONE on success, or an error code.
 */

OGRErr OGRGeometry::transformTo( OGRSpatialReference *poSR )

{
#ifdef DISABLE_OGRGEOM_TRANSFORM
    return OGRERR_FAILURE;
#else
    OGRCoordinateTransformation *poCT;
    OGRErr eErr;

    if( getSpatialReference() == NULL || poSR == NULL )
        return OGRERR_FAILURE;

    poCT = OGRCreateCoordinateTransformation( getSpatialReference(), poSR );
    if( poCT == NULL )
        return OGRERR_FAILURE;

    eErr = transform( poCT );

    delete poCT;

    return eErr;
#endif
}

/************************************************************************/
/*                         OGR_G_TransformTo()                          */
/************************************************************************/
/**
 * Transform geometry to new spatial reference system.
 *
 * This function will transform the coordinates of a geometry from
 * their current spatial reference system to a new target spatial
 * reference system.  Normally this means reprojecting the vectors,
 * but it could include datum shifts, and changes of units. 
 *
 * This function will only work if the geometry already has an assigned
 * spatial reference system, and if it is transformable to the target
 * coordinate system.
 *
 * Because this function requires internal creation and initialization of an
 * OGRCoordinateTransformation object it is significantly more expensive to
 * use this function to transform many geometries than it is to create the
 * OGRCoordinateTransformation in advance, and call transform() with that
 * transformation.  This function exists primarily for convenience when only
 * transforming a single geometry.
 *
 * This function is the same as the CPP method OGRGeometry::transformTo.
 * 
 * @param hGeom handle on the geometry to apply the transform to.
 * @param hSRS handle on the spatial reference system to apply.
 *
 * @return OGRERR_NONE on success, or an error code.
 */

OGRErr OGR_G_TransformTo( OGRGeometryH hGeom, OGRSpatialReferenceH hSRS )