ogrpoint.cpp

用于读取TAB、MIF、SHP文件的类

/*      Get the byte order byte.                                        */
/* -------------------------------------------------------------------- */
    eByteOrder = DB2_V72_FIX_BYTE_ORDER((OGRwkbByteOrder) *pabyData);
    assert( eByteOrder == wkbXDR || eByteOrder == wkbNDR );

/* -------------------------------------------------------------------- */
/*      Get the geometry feature type.  For now we assume that          */
/*      geometry type is between 0 and 255 so we only have to fetch     */
/*      one byte.                                                       */
/* -------------------------------------------------------------------- */
    OGRwkbGeometryType eGeometryType;
    int                bIs3D;
    
    if( eByteOrder == wkbNDR )
    {
        eGeometryType = (OGRwkbGeometryType) pabyData[1];
        bIs3D = pabyData[4] & 0x80 || pabyData[2] & 0x80;
    }
    else
    {
        eGeometryType = (OGRwkbGeometryType) pabyData[4];
        bIs3D = pabyData[1] & 0x80 || pabyData[3] & 0x80;
    }

    assert( eGeometryType == wkbPoint );

/* -------------------------------------------------------------------- */
/*      Get the vertex.                                                 */
/* -------------------------------------------------------------------- */
    memcpy( &x, pabyData + 5, 16 );
    
    if( OGR_SWAP( eByteOrder ) )
    {
        CPL_SWAPDOUBLE( &x );
        CPL_SWAPDOUBLE( &y );
    }

    if( bIs3D )
    {
        memcpy( &z, pabyData + 5 + 16, 8 );
        if( OGR_SWAP( eByteOrder ) )
        {
            CPL_SWAPDOUBLE( &z );
        }
        nCoordDimension = 3;
    }
    else
    {
        z = 0;
        nCoordDimension = 2;
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                            exportToWkb()                             */
/*                                                                      */
/*      Build a well known binary representation of this object.        */
/************************************************************************/

OGRErr  OGRPoint::exportToWkb( OGRwkbByteOrder eByteOrder,
                               unsigned char * pabyData ) const

{
/* -------------------------------------------------------------------- */
/*      Set the byte order.                                             */
/* -------------------------------------------------------------------- */
    pabyData[0] = DB2_V72_UNFIX_BYTE_ORDER((unsigned char) eByteOrder);

/* -------------------------------------------------------------------- */
/*      Set the geometry feature type.                                  */
/* -------------------------------------------------------------------- */
    GUInt32 nGType = getGeometryType();
    
    if( eByteOrder == wkbNDR )
        nGType = CPL_LSBWORD32( nGType );
    else
        nGType = CPL_MSBWORD32( nGType );

    memcpy( pabyData + 1, &nGType, 4 );
    
/* -------------------------------------------------------------------- */
/*      Copy in the raw data.                                           */
/* -------------------------------------------------------------------- */
    memcpy( pabyData+5, &x, 16 );

    if( nCoordDimension == 3 )
    {
        memcpy( pabyData + 5 + 16, &z, 8 );
    }
    
/* -------------------------------------------------------------------- */
/*      Swap if needed.                                                 */
/* -------------------------------------------------------------------- */
    if( OGR_SWAP( eByteOrder ) )
    {
        CPL_SWAPDOUBLE( pabyData + 5 );
        CPL_SWAPDOUBLE( pabyData + 5 + 8 );

        if( nCoordDimension == 3 )
            CPL_SWAPDOUBLE( pabyData + 5 + 16 );
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                           importFromWkt()                            */
/*                                                                      */
/*      Instantiate point from well known text format ``POINT           */
/*      (x,y)''.                                                        */
/************************************************************************/

OGRErr OGRPoint::importFromWkt( char ** ppszInput )

{
    char        szToken[OGR_WKT_TOKEN_MAX];
    const char  *pszInput = *ppszInput;

/* -------------------------------------------------------------------- */
/*      Read and verify the ``POINT'' keyword token.                    */
/* -------------------------------------------------------------------- */
    pszInput = OGRWktReadToken( pszInput, szToken );

    if( !EQUAL(szToken,"POINT") )
        return OGRERR_CORRUPT_DATA;

/* -------------------------------------------------------------------- */
/*      Check for EMPTY ... but treat like a point at 0,0.              */
/* -------------------------------------------------------------------- */
    const char *pszPreScan;

    pszPreScan = OGRWktReadToken( pszInput, szToken );
    if( EQUAL(szToken,"EMPTY") )
    {
        *ppszInput = (char *) pszInput;
        empty();
        return OGRERR_NONE;
    }

    if( !EQUAL(szToken,"(") )
        return OGRERR_CORRUPT_DATA;

    pszPreScan = OGRWktReadToken( pszPreScan, szToken );
    if( EQUAL(szToken,"EMPTY") )
    {
        pszInput = OGRWktReadToken( pszPreScan, szToken );
        
        if( !EQUAL(szToken,")") )
            return OGRERR_CORRUPT_DATA;
        else
        {
            *ppszInput = (char *) pszInput;
            empty();
            return OGRERR_NONE;
        }
    }

/* -------------------------------------------------------------------- */
/*      Read the point list which should consist of exactly one point.  */
/* -------------------------------------------------------------------- */
    OGRRawPoint         *poPoints = NULL;
    double              *padfZ = NULL;
    int                 nMaxPoint = 0, nPoints = 0;

    pszInput = OGRWktReadPoints( pszInput, &poPoints, &padfZ,
                                 &nMaxPoint, &nPoints );
    if( pszInput == NULL || nPoints != 1 )
        return OGRERR_CORRUPT_DATA;

    x = poPoints[0].x;
    y = poPoints[0].y;

    CPLFree( poPoints );

    if( padfZ != NULL )
    {
        z = padfZ[0];						
        nCoordDimension = 3;
        CPLFree( padfZ );
    }
    else
        nCoordDimension = 2;

    *ppszInput = (char *) pszInput;
    
    return OGRERR_NONE;
}

/************************************************************************/
/*                            exportToWkt()                             */
/*                                                                      */
/*      Translate this structure into it's well known text format       */
/*      equivelent.                                                     */
/************************************************************************/

OGRErr OGRPoint::exportToWkt( char ** ppszDstText ) const

{
    char        szTextEquiv[140];
    char        szCoordinate[80];

    OGRMakeWktCoordinate(szCoordinate, x, y, z, nCoordDimension );
    sprintf( szTextEquiv, "POINT (%s)", szCoordinate );
    *ppszDstText = CPLStrdup( szTextEquiv );
    
    return OGRERR_NONE;
}

/************************************************************************/
/*                            getEnvelope()                             */
/************************************************************************/

void OGRPoint::getEnvelope( OGREnvelope * psEnvelope ) const

{
    psEnvelope->MinX = psEnvelope->MaxX = getX();
    psEnvelope->MinY = psEnvelope->MaxY = getY();
}



/**
 * \fn double OGRPoint::getX() const;
 *
 * Fetch X coordinate.
 *
 * Relates to the SFCOM IPoint::get_X() method.
 *
 * @return the X coordinate of this point. 
 */

/**
 * \fn double OGRPoint::getY() const;
 *
 * Fetch Y coordinate.
 *
 * Relates to the SFCOM IPoint::get_Y() method.
 *
 * @return the Y coordinate of this point. 
 */

/**
 * \fn double OGRPoint::getZ() const;
 *
 * Fetch Z coordinate.
 *
 * Relates to the SFCOM IPoint::get_Z() method.
 *
 * @return the Z coordinate of this point, or zero if it is a 2D point.
 */

/**
 * \fn void OGRPoint::setX( double xIn );
 *
 * Assign point X coordinate.
 *
 * There is no corresponding SFCOM method.
 */ 

/**
 * \fn void OGRPoint::setY( double yIn );
 *
 * Assign point Y coordinate.
 *
 * There is no corresponding SFCOM method.
 */ 

/**
 * \fn void OGRPoint::setZ( double zIn );
 *
 * Assign point Z coordinate.  Setting a zero zIn value will make the point
 * 2D, and setting a non-zero value will make the point 3D (wkbPoint|wkbZ).
 *
 * There is no corresponding SFCOM method.  
 */ 

/************************************************************************/
/*                               Equal()                                */
/************************************************************************/

OGRBoolean OGRPoint::Equals( OGRGeometry * poOther ) const

{
    OGRPoint    *poOPoint = (OGRPoint *) poOther;
    
    if( poOPoint== this )
        return TRUE;
    
    if( poOther->getGeometryType() != getGeometryType() )
        return FALSE;

    // we should eventually test the SRS.
    
    if( poOPoint->getX() != getX()
        || poOPoint->getY() != getY()
        || poOPoint->getZ() != getZ() )
        return FALSE;
    else
        return TRUE;
}

/************************************************************************/
/*                             transform()                              */
/************************************************************************/

OGRErr OGRPoint::transform( OGRCoordinateTransformation *poCT )

{
#ifdef DISABLE_OGRGEOM_TRANSFORM
    return OGRERR_FAILURE;
#else
    if( poCT->Transform( 1, &x, &y, &z ) )
    {
        assignSpatialReference( poCT->GetTargetCS() );
        return OGRERR_NONE;
    }
    else
        return OGRERR_FAILURE;
#endif
}