pj_apply_gridshift.c
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/******************************************************************************
* $Id: pj_apply_gridshift.c,v 1.8 2003/03/20 21:29:41 warmerda Exp $
*
* Project: PROJ.4
* Purpose: Apply datum shifts based on grid shift files (normally NAD27 to
* NAD83 or the reverse). This module is responsible for keeping
* a list of loaded grids, and calling with each one that is
* allowed for a given datum (expressed as the nadgrids= parameter).
* Author: Frank Warmerdam, warmerdam@pobox.com
*
******************************************************************************
* Copyright (c) 2000, Frank Warmerdam <warmerdam@pobox.com>
*
* 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: pj_apply_gridshift.c,v $
* Revision 1.8 2003/03/20 21:29:41 warmerda
* Fixed bug in checking against grid bounds.
*
* Revision 1.7 2003/03/17 19:45:23 warmerda
* improved error handling
*
* Revision 1.6 2003/03/17 18:56:34 warmerda
* implement heirarchical NTv2 gridinfos
*
* Revision 1.5 2003/03/15 06:02:02 warmerda
* preliminary NTv2 support, major restructure of datum shifting
*
* Revision 1.4 2002/07/08 02:32:05 warmerda
* ensure clean C++ builds
*
* Revision 1.3 2002/04/30 16:27:27 warmerda
* improve debug output
*
* Revision 1.2 2001/03/15 16:57:55 warmerda
* fixed intermittent problem in pj_load_nadgrids()
*
* Revision 1.1 2000/07/06 23:32:27 warmerda
* New
*
*/
#define PJ_LIB__
#include "projects.h"
#include <string.h>
#include <math.h>
/************************************************************************/
/* pj_apply_gridshift() */
/************************************************************************/
int pj_apply_gridshift( const char *nadgrids, int inverse,
long point_count, int point_offset,
double *x, double *y, double *z )
{
int grid_count = 0;
PJ_GRIDINFO **tables;
int i;
int debug_flag = getenv( "PROJ_DEBUG" ) != NULL;
static int debug_count = 0;
pj_errno = 0;
tables = pj_gridlist_from_nadgrids( nadgrids, &grid_count);
if( tables == NULL || grid_count == 0 )
return pj_errno;
for( i = 0; i < point_count; i++ )
{
long io = i * point_offset;
LP input, output;
int itable;
input.phi = y[io];
input.lam = x[io];
output.phi = HUGE_VAL;
output.lam = HUGE_VAL;
/* keep trying till we find a table that works */
for( itable = 0; itable < grid_count; itable++ )
{
PJ_GRIDINFO *gi = tables[itable];
struct CTABLE *ct = gi->ct;
/* skip tables that don't match our point at all. */
if( ct->ll.phi > input.phi || ct->ll.lam > input.lam
|| ct->ll.phi + (ct->lim.phi-1) * ct->del.phi < input.phi
|| ct->ll.lam + (ct->lim.lam-1) * ct->del.lam < input.lam )
continue;
/* If we have child nodes, check to see if any of them apply. */
if( gi->child != NULL )
{
PJ_GRIDINFO *child;
for( child = gi->child; child != NULL; child = child->next )
{
struct CTABLE *ct1 = child->ct;
if( ct1->ll.phi > input.phi || ct1->ll.lam > input.lam
|| ct1->ll.phi+(ct1->lim.phi-1)*ct1->del.phi < input.phi
|| ct1->ll.lam+(ct1->lim.lam-1)*ct1->del.lam < input.lam)
continue;
break;
}
/* we found a more refined child node to use */
if( child != NULL )
{
gi = child;
ct = child->ct;
}
}
/* load the grid shift info if we don't have it. */
if( ct->cvs == NULL && !pj_gridinfo_load( gi ) )
{
pj_errno = -38;
return pj_errno;
}
output = nad_cvt( input, inverse, ct );
if( output.lam != HUGE_VAL )
{
if( debug_flag && debug_count++ < 20 )
fprintf( stderr,
"pj_apply_gridshift(): used %s\n",
ct->id );
break;
}
}
if( output.lam == HUGE_VAL )
{
if( debug_flag )
{
fprintf( stderr,
"pj_apply_gridshift(): failed to find a grid shift table for\n"
" location (%.7fdW,%.7fdN)\n",
x[io] * RAD_TO_DEG,
y[io] * RAD_TO_DEG );
fprintf( stderr,
" tried: %s\n", nadgrids );
}
pj_errno = -38;
return pj_errno;
}
else
{
y[io] = output.phi;
x[io] = output.lam;
}
}
return 0;
}