summaryrefslogtreecommitdiff
path: root/src/3rdparty/proj/PJ_tmerc.c
blob: 14cf2e8e5be8253b9e50f02fe8e6c13657e13e1e (plain)
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
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
#define PROJ_PARMS__ \
	double	esp; \
	double	ml0; \
	double	*en;
#define PJ_LIB__
#include	<projects.h>
PROJ_HEAD(tmerc, "Transverse Mercator") "\n\tCyl, Sph&Ell";
PROJ_HEAD(utm, "Universal Transverse Mercator (UTM)")
	"\n\tCyl, Sph\n\tzone= south";
#define EPS10	1.e-10
#define aks0	P->esp
#define aks5	P->ml0
#define FC1 1.
#define FC2 .5
#define FC3 .16666666666666666666
#define FC4 .08333333333333333333
#define FC5 .05
#define FC6 .03333333333333333333
#define FC7 .02380952380952380952
#define FC8 .01785714285714285714
FORWARD(e_forward); /* ellipse */
	double al, als, n, cosphi, sinphi, t;

        /*
         * Fail if our longitude is more than 90 degrees from the 
         * central meridian since the results are essentially garbage. 
         * Is error -20 really an appropriate return value?
         * 
         *  http://trac.osgeo.org/proj/ticket/5
         */
        if( lp.lam < -HALFPI || lp.lam > HALFPI )
        {
            xy.x = HUGE_VAL;
            xy.y = HUGE_VAL;
            pj_errno = -14;
            return xy;
        }

	sinphi = sin(lp.phi); cosphi = cos(lp.phi);
	t = fabs(cosphi) > 1e-10 ? sinphi/cosphi : 0.;
	t *= t;
	al = cosphi * lp.lam;
	als = al * al;
	al /= sqrt(1. - P->es * sinphi * sinphi);
	n = P->esp * cosphi * cosphi;
	xy.x = P->k0 * al * (FC1 +
		FC3 * als * (1. - t + n +
		FC5 * als * (5. + t * (t - 18.) + n * (14. - 58. * t)
		+ FC7 * als * (61. + t * ( t * (179. - t) - 479. ) )
		)));
	xy.y = P->k0 * (pj_mlfn(lp.phi, sinphi, cosphi, P->en) - P->ml0 +
		sinphi * al * lp.lam * FC2 * ( 1. +
		FC4 * als * (5. - t + n * (9. + 4. * n) +
		FC6 * als * (61. + t * (t - 58.) + n * (270. - 330 * t)
		+ FC8 * als * (1385. + t * ( t * (543. - t) - 3111.) )
		))));
	return (xy);
}
FORWARD(s_forward); /* sphere */
	double b, cosphi;

        /*
         * Fail if our longitude is more than 90 degrees from the 
         * central meridian since the results are essentially garbage. 
         * Is error -20 really an appropriate return value?
         * 
         *  http://trac.osgeo.org/proj/ticket/5
         */
        if( lp.lam < -HALFPI || lp.lam > HALFPI )
        {
            xy.x = HUGE_VAL;
            xy.y = HUGE_VAL;
            pj_errno = -14;
            return xy;
        }

	b = (cosphi = cos(lp.phi)) * sin(lp.lam);
	if (fabs(fabs(b) - 1.) <= EPS10) F_ERROR;
	xy.x = aks5 * log((1. + b) / (1. - b));
	if ((b = fabs( xy.y = cosphi * cos(lp.lam) / sqrt(1. - b * b) )) >= 1.) {
		if ((b - 1.) > EPS10) F_ERROR
		else xy.y = 0.;
	} else
		xy.y = acos(xy.y);
	if (lp.phi < 0.) xy.y = -xy.y;
	xy.y = aks0 * (xy.y - P->phi0);
	return (xy);
}
INVERSE(e_inverse); /* ellipsoid */
	double n, con, cosphi, d, ds, sinphi, t;

	lp.phi = pj_inv_mlfn(P->ml0 + xy.y / P->k0, P->es, P->en);
	if (fabs(lp.phi) >= HALFPI) {
		lp.phi = xy.y < 0. ? -HALFPI : HALFPI;
		lp.lam = 0.;
	} else {
		sinphi = sin(lp.phi);
		cosphi = cos(lp.phi);
		t = fabs(cosphi) > 1e-10 ? sinphi/cosphi : 0.;
		n = P->esp * cosphi * cosphi;
		d = xy.x * sqrt(con = 1. - P->es * sinphi * sinphi) / P->k0;
		con *= t;
		t *= t;
		ds = d * d;
		lp.phi -= (con * ds / (1.-P->es)) * FC2 * (1. -
			ds * FC4 * (5. + t * (3. - 9. *  n) + n * (1. - 4 * n) -
			ds * FC6 * (61. + t * (90. - 252. * n +
				45. * t) + 46. * n
		   - ds * FC8 * (1385. + t * (3633. + t * (4095. + 1574. * t)) )
			)));
		lp.lam = d*(FC1 -
			ds*FC3*( 1. + 2.*t + n -
			ds*FC5*(5. + t*(28. + 24.*t + 8.*n) + 6.*n
		   - ds * FC7 * (61. + t * (662. + t * (1320. + 720. * t)) )
		))) / cosphi;
	}
	return (lp);
}
INVERSE(s_inverse); /* sphere */
	double h, g;

	h = exp(xy.x / aks0);
	g = .5 * (h - 1. / h);
	h = cos(P->phi0 + xy.y / aks0);
	lp.phi = asin(sqrt((1. - h * h) / (1. + g * g)));
	if (xy.y < 0.) lp.phi = -lp.phi;
	lp.lam = (g || h) ? atan2(g, h) : 0.;
	return (lp);
}
FREEUP;
	if (P) {
		if (P->en)
			pj_dalloc(P->en);
		pj_dalloc(P);
	}
}
	static PJ *
setup(PJ *P) { /* general initialization */
	if (P->es) {
		if (!(P->en = pj_enfn(P->es)))
			E_ERROR_0;
		P->ml0 = pj_mlfn(P->phi0, sin(P->phi0), cos(P->phi0), P->en);
		P->esp = P->es / (1. - P->es);
		P->inv = e_inverse;
		P->fwd = e_forward;
	} else {
		aks0 = P->k0;
		aks5 = .5 * aks0;
		P->inv = s_inverse;
		P->fwd = s_forward;
	}
	return P;
}
ENTRY1(tmerc, en)
ENDENTRY(setup(P))
ENTRY1(utm, en)
	int zone;

	if (!P->es) E_ERROR(-34);
	P->y0 = pj_param(P->params, "bsouth").i ? 10000000. : 0.;
	P->x0 = 500000.;
	if (pj_param(P->params, "tzone").i) /* zone input ? */
		if ((zone = pj_param(P->params, "izone").i) > 0 && zone <= 60)
			--zone;
		else
			E_ERROR(-35)
	else /* nearest central meridian input */
		if ((zone = floor((adjlon(P->lam0) + PI) * 30. / PI)) < 0)
			zone = 0;
		else if (zone >= 60)
			zone = 59;
	P->lam0 = (zone + .5) * PI / 30. - PI;
	P->k0 = 0.9996;
	P->phi0 = 0.;
ENDENTRY(setup(P))