PJ_airy.c
3.65 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
/******************************************************************************
* $Id: PJ_airy.c,v 1.2 2002/12/14 19:30:40 warmerda Exp $
*
* Project: PROJ.4
* Purpose: Implementation of the airy (Airy) projection.
* 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.
******************************************************************************
*
* $Log: PJ_airy.c,v $
* Revision 1.2 2002/12/14 19:30:40 warmerda
* updated header
*
*/
#define PROJ_PARMS__ \
double p_halfpi; \
double sinph0; \
double cosph0; \
double Cb; \
int mode; \
int no_cut; /* do not cut at hemisphere limit */
#define PJ_LIB__
#include "projects.h"
PJ_CVSID("$Id: PJ_airy.c,v 1.2 2002/12/14 19:30:40 warmerda Exp $");
PROJ_HEAD(airy, "Airy") "\n\tMisc Sph, no inv.\n\tno_cut lat_b=";
# define EPS 1.e-10
# define N_POLE 0
# define S_POLE 1
# define EQUIT 2
# define OBLIQ 3
FORWARD(s_forward); /* spheroid */
double sinlam, coslam, cosphi, sinphi, t, s, Krho, cosz;
sinlam = sin(lp.lam);
coslam = cos(lp.lam);
switch (P->mode) {
case EQUIT:
case OBLIQ:
sinphi = sin(lp.phi);
cosphi = cos(lp.phi);
cosz = cosphi * coslam;
if (P->mode == OBLIQ)
cosz = P->sinph0 * sinphi + P->cosph0 * cosz;
if (!P->no_cut && cosz < -EPS)
F_ERROR;
if (fabs(s = 1. - cosz) > EPS) {
t = 0.5 * (1. + cosz);
Krho = -log(t)/s - P->Cb / t;
} else
Krho = 0.5 - P->Cb;
xy.x = Krho * cosphi * sinlam;
if (P->mode == OBLIQ)
xy.y = Krho * (P->cosph0 * sinphi -
P->sinph0 * cosphi * coslam);
else
xy.y = Krho * sinphi;
break;
case S_POLE:
case N_POLE:
lp.phi = fabs(P->p_halfpi - lp.phi);
if (!P->no_cut && (lp.phi - EPS) > HALFPI)
F_ERROR;
if ((lp.phi *= 0.5) > EPS) {
t = tan(lp.phi);
Krho = -2.*(log(cos(lp.phi)) / t + t * P->Cb);
xy.x = Krho * sinlam;
xy.y = Krho * coslam;
if (P->mode == N_POLE)
xy.y = -xy.y;
} else
xy.x = xy.y = 0.;
}
return (xy);
}
FREEUP; if (P) pj_dalloc(P); }
ENTRY0(airy)
double beta;
P->no_cut = pj_param(P->params, "bno_cut").i;
beta = 0.5 * (HALFPI - pj_param(P->params, "rlat_b").f);
if (fabs(beta) < EPS)
P->Cb = -0.5;
else {
P->Cb = 1./tan(beta);
P->Cb *= P->Cb * log(cos(beta));
}
if (fabs(fabs(P->phi0) - HALFPI) < EPS)
if (P->phi0 < 0.) {
P->p_halfpi = -HALFPI;
P->mode = S_POLE;
} else {
P->p_halfpi = HALFPI;
P->mode = N_POLE;
}
else {
if (fabs(P->phi0) < EPS)
P->mode = EQUIT;
else {
P->mode = OBLIQ;
P->sinph0 = sin(P->phi0);
P->cosph0 = cos(P->phi0);
}
}
P->fwd = s_forward;
P->es = 0.;
ENDENTRY(P)