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/******************************************************************************
* 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.
*****************************************************************************/
#define PJ_LIB__
#include <projects.h>
#include <string.h>
#include <math.h>
/************************************************************************/
/* pj_apply_gridshift() */
/* */
/* This is the externally callable interface - part of the */
/* public API - though it is not used internally any more and I */
/* doubt it is used by any other applications. But we preserve */
/* it to honour our public api. */
/************************************************************************/
int pj_apply_gridshift( projCtx ctx, const char *nadgrids, int inverse,
long point_count, int point_offset,
double *x, double *y, double *z )
{
PJ_GRIDINFO **gridlist;
int grid_count;
int ret;
gridlist = pj_gridlist_from_nadgrids( ctx, nadgrids, &grid_count );
if( gridlist == NULL || grid_count == 0 )
return ctx->last_errno;
ret = pj_apply_gridshift_3( ctx, gridlist, grid_count, inverse,
point_count, point_offset, x, y, z );
/*
** Note this frees the array of grid list pointers, but not the grids
** which is as intended. The grids themselves live on.
*/
pj_dalloc( gridlist );
return ret;
}
/************************************************************************/
/* pj_apply_gridshift_2() */
/* */
/* This implementation takes uses the gridlist from a coordinate */
/* system definition. If the gridlist has not yet been */
/* populated in the coordinate system definition we set it up */
/* now. */
/************************************************************************/
int pj_apply_gridshift_2( PJ *defn, int inverse,
long point_count, int point_offset,
double *x, double *y, double *z )
{
if( defn->catalog_name != NULL )
return pj_gc_apply_gridshift( defn, inverse, point_count, point_offset,
x, y, z );
if( defn->gridlist == NULL )
{
defn->gridlist =
pj_gridlist_from_nadgrids( pj_get_ctx( defn ),
pj_param(defn->ctx, defn->params,"snadgrids").s,
&(defn->gridlist_count) );
if( defn->gridlist == NULL || defn->gridlist_count == 0 )
return defn->ctx->last_errno;
}
return pj_apply_gridshift_3( pj_get_ctx( defn ),
defn->gridlist, defn->gridlist_count, inverse,
point_count, point_offset, x, y, z );
}
/************************************************************************/
/* pj_apply_gridshift_3() */
/* */
/* This is the real workhorse, given a gridlist. */
/************************************************************************/
int pj_apply_gridshift_3( projCtx ctx, PJ_GRIDINFO **tables, int grid_count,
int inverse, long point_count, int point_offset,
double *x, double *y, double *z )
{
int i;
static int debug_count = 0;
(void) z;
if( tables == NULL || grid_count == 0 )
{
pj_ctx_set_errno( ctx, -38);
return -38;
}
ctx->last_errno = 0;
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;
double epsilon = (fabs(ct->del.phi)+fabs(ct->del.lam))/10000.0;
/* skip tables that don't match our point at all. */
if( ct->ll.phi - epsilon > input.phi
|| ct->ll.lam - epsilon > input.lam
|| (ct->ll.phi + (ct->lim.phi-1) * ct->del.phi + epsilon
< input.phi)
|| (ct->ll.lam + (ct->lim.lam-1) * ct->del.lam + epsilon
< input.lam) )
continue;
/* If we have child nodes, check to see if any of them apply. */
while( gi->child )
{
PJ_GRIDINFO *child;
for( child = gi->child; child != NULL; child = child->next )
{
struct CTABLE *ct1 = child->ct;
double epsilon =
(fabs(ct1->del.phi)+fabs(ct1->del.lam))/10000.0;
if( ct1->ll.phi - epsilon > input.phi
|| ct1->ll.lam - epsilon > input.lam
|| (ct1->ll.phi+(ct1->lim.phi-1)*ct1->del.phi + epsilon
< input.phi)
|| (ct1->ll.lam+(ct1->lim.lam-1)*ct1->del.lam + epsilon
< input.lam) )
continue;
break;
}
/* If we didn't find a child then nothing more to do */
if( child == NULL ) break;
/* Otherwise use the child, first checking it's children */
gi = child;
ct = child->ct;
}
/* load the grid shift info if we don't have it. */
if( ct->cvs == NULL && !pj_gridinfo_load( ctx, gi ) )
{
pj_ctx_set_errno( ctx, -38 );
return -38;
}
output = nad_cvt( input, inverse, ct );
if( output.lam != HUGE_VAL )
{
if( debug_count++ < 20 )
pj_log( ctx, PJ_LOG_DEBUG_MINOR,
"pj_apply_gridshift(): used %s", ct->id );
break;
}
}
if( output.lam == HUGE_VAL )
{
if( ctx->debug_level >= PJ_LOG_DEBUG_MAJOR )
{
pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
"pj_apply_gridshift(): failed to find a grid shift table for\n"
" location (%.7fdW,%.7fdN)",
x[io] * RAD_TO_DEG,
y[io] * RAD_TO_DEG );
for( itable = 0; itable < grid_count; itable++ )
{
PJ_GRIDINFO *gi = tables[itable];
if( itable == 0 )
pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
" tried: %s", gi->gridname );
else
pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
",%s", gi->gridname );
}
}
/*
* We don't actually have any machinery currently to set the
* following macro, so this is mostly kept here to make it clear
* how we ought to operate if we wanted to make it super clear
* that an error has occurred when points are outside our available
* datum shift areas. But if this is on, we will find that "low
* value" points on the fringes of some datasets will completely
* fail causing lots of problems when it is more or less ok to
* just not apply a datum shift. So rather than deal with
* that we just fallback to no shift. (see also bug #45).
*/
#ifdef ERR_GRID_AREA_TRANSIENT_SEVERE
y[io] = HUGE_VAL;
x[io] = HUGE_VAL;
#else
/* leave x/y unshifted. */
#endif
}
else
{
y[io] = output.phi;
x[io] = output.lam;
}
}
return 0;
}
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