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geo_trans.c

/******************************************************************************
 * $Id: geo_trans_c-source.html 385 2001-03-05 04:58:33Z warmerda $
 *
 * Project:  libgeotiff
 * Purpose:  Code to abstract translation between pixel/line and PCS
 *           coordinates.
 * Author:   Frank Warmerdam, warmerda@home.com
 *
 ******************************************************************************
 * 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.
 ******************************************************************************
 *
 * $Log$
 * Revision 1.2  2001/03/05 04:58:33  warmerda
 * updated
 *
 * Revision 1.7  2001/03/05 03:25:23  warmerda
 * restructure cleanup, and apply to GTIFPCSToImage()
 *
 * Revision 1.6  2001/03/04 22:37:39  warmerda
 * fixed memory leak for fields fetched with gt_methods.get - Alan Gray
 *
 * Revision 1.5  2000/08/22 03:32:46  warmerda
 * removed GTIFTiepointTranslate code
 *
 * Revision 1.4  1999/09/17 01:19:51  warmerda
 * Fixed bug in use of transform matrix.
 *
 * Revision 1.3  1999/09/16 21:25:40  warmerda
 * Added tiepoint, and transformation matrix based translation.  Note
 * that we don't try to invert the transformation matrix for
 * GTIFPCSToImage().
 *
 * Revision 1.2  1999/09/07 20:00:40  warmerda
 * Fixed count/tiepoint_count bug in GTIFPCSToImage().
 *
 * Revision 1.1  1999/05/04 03:07:57  warmerda
 * New
 *
 */
 
#include "geotiff.h"
#include "geo_tiffp.h" /* external TIFF interface */
#include "geo_keyp.h"  /* private interface       */
#include "geokeys.h"

/************************************************************************/
/*                       GTIFTiepointTranslate()                        */
/************************************************************************/

int GTIFTiepointTranslate( int gcp_count, double * gcps_in, double * gcps_out,
                           double x_in, double y_in,
                           double *x_out, double *y_out )

{
    /* I would appreciate a _brief_ block of code for doing second order
       polynomial regression here! */
    return FALSE;
}


/************************************************************************/
/*                           GTIFImageToPCS()                           */
/************************************************************************/

int GTIFImageToPCS( GTIF *gtif, double *x, double *y )

{
    int     res = FALSE;
    int     tiepoint_count, count, transform_count;
    tiff_t *tif=gtif->gt_tif;
    double *tiepoints   = 0;
    double *pixel_scale = 0;
    double *transform   = 0;


    if (!(gtif->gt_methods.get)(tif, GTIFF_TIEPOINTS,
                              &tiepoint_count, &tiepoints ))
        tiepoint_count = 0;

    if (!(gtif->gt_methods.get)(tif, GTIFF_PIXELSCALE, &count, &pixel_scale ))
        count = 0;

    if (!(gtif->gt_methods.get)(tif, GTIFF_TRANSMATRIX,
                                &transform_count, &transform ))
        transform_count = 0;

/* -------------------------------------------------------------------- */
/*      If the pixelscale count is zero, but we have tiepoints use      */
/*      the tiepoint based approach.                                    */
/* -------------------------------------------------------------------- */
    if( tiepoint_count > 6 && count == 0 ) 
    {
        res = GTIFTiepointTranslate( tiepoint_count / 6,
                                     tiepoints, tiepoints + 3,
                                     *x, *y, x, y );
    }

/* -------------------------------------------------------------------- */
/*      If we have a transformation matrix, use it.                     */
/* -------------------------------------------------------------------- */
    else if( transform_count == 16 ) 
    {
        double x_in = *x, y_in = *y;

        *x = x_in * transform[0] + y_in * transform[1] + transform[3];
        *y = x_in * transform[4] + y_in * transform[5] + transform[7];
        
        res = TRUE;
    } 

/* -------------------------------------------------------------------- */
/*      For now we require one tie point, and a valid pixel scale.      */
/* -------------------------------------------------------------------- */
    else if( count < 3 || tiepoint_count < 6 ) 
    {
        res = FALSE;
    } 

    else 
    {
        *x = (*x - tiepoints[0]) * pixel_scale[0] + tiepoints[3];
        *y = (*y - tiepoints[1]) * (-1 * pixel_scale[1]) + tiepoints[4];

        res = TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Cleanup                                                         */
/* -------------------------------------------------------------------- */
    if(tiepoints)   
        _GTIFFree(tiepoints);
    if(pixel_scale)
        _GTIFFree(pixel_scale);
    if(transform)  
        _GTIFFree(transform);

    return res;
}

/************************************************************************/
/*                           GTIFPCSToImage()                           */
/************************************************************************/

int GTIFPCSToImage( GTIF *gtif, double *x, double *y )

{
    double      *tiepoints;
    int         tiepoint_count, count;
    double      *pixel_scale;
    tiff_t *tif=gtif->gt_tif;
    int         result = FALSE;

/* -------------------------------------------------------------------- */
/*      Fetch tiepoints and pixel scale.                                */
/* -------------------------------------------------------------------- */
    if (!(gtif->gt_methods.get)(tif, GTIFF_TIEPOINTS,
                              &tiepoint_count, &tiepoints ))
        tiepoint_count = 0;

    if (!(gtif->gt_methods.get)(tif, GTIFF_PIXELSCALE, &count, &pixel_scale ))
        count = 0;

/* -------------------------------------------------------------------- */
/*      If the pixelscale count is zero, but we have tiepoints use      */
/*      the tiepoint based approach.                                    */
/* -------------------------------------------------------------------- */
    if( tiepoint_count > 6 && count == 0 )
    {
        result = GTIFTiepointTranslate( tiepoint_count / 6,
                                        tiepoints + 3, tiepoints,
                                        *x, *y, x, y );
    }
    
/* -------------------------------------------------------------------- */
/*      For now we require one tie point, and a valid pixel scale.      */
/* -------------------------------------------------------------------- */
    else if( count >= 3 && tiepoint_count >= 6 )
    {
        *x = (*x - tiepoints[3]) / pixel_scale[0] + tiepoints[0];
        *y = (*y - tiepoints[4]) / (-1 * pixel_scale[1]) + tiepoints[1];

        result = TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Cleanup.                                                        */
/* -------------------------------------------------------------------- */
    if(tiepoints)   
        _GTIFFree(tiepoints);
    if(pixel_scale)
        _GTIFFree(pixel_scale);

    return result;
}

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