PJ_aitoff.c
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/******************************************************************************
* $Id: PJ_aitoff.c 1504 2009-01-06 02:11:57Z warmerdam $
*
* Project: PROJ.4
* Purpose: Implementation of the aitoff (Aitoff) and wintri (Winkel Tripel)
* projections.
* Author: Gerald Evenden
*
******************************************************************************
* Copyright (c) 1995, Gerald Evenden
*
* 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 PROJ_PARMS__ \
double cosphi1; \
int mode;
#define PJ_LIB__
#include <projects.h>
PJ_CVSID("$Id: PJ_aitoff.c 1504 2009-01-06 02:11:57Z warmerdam $");
PROJ_HEAD(aitoff, "Aitoff") "\n\tMisc Sph";
PROJ_HEAD(wintri, "Winkel Tripel") "\n\tMisc Sph\n\tlat_1";
FORWARD(s_forward); /* spheroid */
double c, d;
if((d = acos(cos(lp.phi) * cos(c = 0.5 * lp.lam)))) {/* basic Aitoff */
xy.x = 2. * d * cos(lp.phi) * sin(c) * (xy.y = 1. / sin(d));
xy.y *= d * sin(lp.phi);
} else
xy.x = xy.y = 0.;
if (P->mode) { /* Winkel Tripel */
xy.x = (xy.x + lp.lam * P->cosphi1) * 0.5;
xy.y = (xy.y + lp.phi) * 0.5;
}
return (xy);
}
FREEUP; if (P) pj_dalloc(P); }
static PJ *
setup(PJ *P) {
P->inv = 0;
P->fwd = s_forward;
P->es = 0.;
return P;
}
ENTRY0(aitoff)
P->mode = 0;
ENDENTRY(setup(P))
ENTRY0(wintri)
P->mode = 1;
if (pj_param(P->params, "tlat_1").i)
{
if ((P->cosphi1 = cos(pj_param(P->params, "rlat_1").f)) == 0.)
E_ERROR(-22)
}
else /* 50d28' or acos(2/pi) */
P->cosphi1 = 0.636619772367581343;
ENDENTRY(setup(P))