/src/proj/src/projections/igh.cpp

Source


#include <errno.h>
#include <math.h>

#include "proj.h"
#include "proj_internal.h"

PROJ_HEAD(igh, "Interrupted Goode Homolosine") "\n\tPCyl, Sph";

/*
This projection is a compilation of 12 separate sub-projections.
Sinusoidal projections are found near the equator and Mollweide
projections are found at higher latitudes. The transition between
the two occurs at 40 degrees latitude and is represented by the
constant `igh_phi_boundary`.

Each sub-projection is assigned an integer label
numbered 1 through 12. Most of this code contains logic to assign
the labels based on latitude (phi) and longitude (lam) regions.

Original Reference:
J. Paul Goode (1925) THE HOMOLOSINE PROJECTION: A NEW DEVICE FOR
    PORTRAYING THE EARTH'S SURFACE ENTIRE, Annals of the Association of
    American Geographers, 15:3, 119-125, DOI: 10.1080/00045602509356949
*/

C_NAMESPACE PJ *pj_sinu(PJ *), *pj_moll(PJ *);

/*
Transition from sinusoidal to Mollweide projection
Latitude (phi): 40deg 44' 11.8"
*/

constexpr double igh_phi_boundary = (40 + 44 / 60. + 11.8 / 3600.) * DEG_TO_RAD;

namespace pj_igh_ns {
struct pj_igh_data {
    struct PJconsts *pj[12];
    double dy0;
};

constexpr double d10 = 10 * DEG_TO_RAD;
constexpr double d20 = 20 * DEG_TO_RAD;
constexpr double d30 = 30 * DEG_TO_RAD;
constexpr double d40 = 40 * DEG_TO_RAD;
constexpr double d50 = 50 * DEG_TO_RAD;
constexpr double d60 = 60 * DEG_TO_RAD;
constexpr double d80 = 80 * DEG_TO_RAD;
constexpr double d90 = 90 * DEG_TO_RAD;
constexpr double d100 = 100 * DEG_TO_RAD;
constexpr double d140 = 140 * DEG_TO_RAD;
constexpr double d160 = 160 * DEG_TO_RAD;
constexpr double d180 = 180 * DEG_TO_RAD;

constexpr double EPSLN =
    1.e-10; /* allow a little 'slack' on zone edge positions */

} // namespace pj_igh_ns

static PJ_XY igh_s_forward(PJ_LP lp, PJ *P) { /* Spheroidal, forward */
    using namespace pj_igh_ns;
    PJ_XY xy;
    struct pj_igh_data *Q = static_cast<struct pj_igh_data *>(P->opaque);
    int z;

    if (lp.phi >= igh_phi_boundary) { /* 1|2 */
        z = (lp.lam <= -d40 ? 1 : 2);
    } else if (lp.phi >= 0) { /* 3|4 */
        z = (lp.lam <= -d40 ? 3 : 4);
    } else if (lp.phi >= -igh_phi_boundary) { /* 5|6|7|8 */
        if (lp.lam <= -d100)
            z = 5; /* 5 */
        else if (lp.lam <= -d20)
            z = 6; /* 6 */
        else if (lp.lam <= d80)
            z = 7; /* 7 */
        else
            z = 8; /* 8 */
    } else {       /* 9|10|11|12 */
        if (lp.lam <= -d100)
            z = 9; /* 9 */
        else if (lp.lam <= -d20)
            z = 10; /* 10 */
        else if (lp.lam <= d80)
            z = 11; /* 11 */
        else
            z = 12; /* 12 */
    }

    lp.lam -= Q->pj[z - 1]->lam0;
    xy = Q->pj[z - 1]->fwd(lp, Q->pj[z - 1]);
    xy.x += Q->pj[z - 1]->x0;
    xy.y += Q->pj[z - 1]->y0;

    return xy;
}

static PJ_LP igh_s_inverse(PJ_XY xy, PJ *P) { /* Spheroidal, inverse */
    using namespace pj_igh_ns;
    PJ_LP lp = {0.0, 0.0};
    struct pj_igh_data *Q = static_cast<struct pj_igh_data *>(P->opaque);
    const double y90 =
        Q->dy0 + sqrt(2.0); /* lt=90 corresponds to y=y0+sqrt(2) */

    int z = 0;
    if (xy.y > y90 + EPSLN || xy.y < -y90 + EPSLN) /* 0 */
        z = 0;
    else if (xy.y >= igh_phi_boundary) /* 1|2 */
        z = (xy.x <= -d40 ? 1 : 2);
    else if (xy.y >= 0) /* 3|4 */
        z = (xy.x <= -d40 ? 3 : 4);
    else if (xy.y >= -igh_phi_boundary) { /* 5|6|7|8 */
        if (xy.x <= -d100)
            z = 5; /* 5 */
        else if (xy.x <= -d20)
            z = 6; /* 6 */
        else if (xy.x <= d80)
            z = 7; /* 7 */
        else
            z = 8; /* 8 */
    } else {       /* 9|10|11|12 */
        if (xy.x <= -d100)
            z = 9; /* 9 */
        else if (xy.x <= -d20)
            z = 10; /* 10 */
        else if (xy.x <= d80)
            z = 11; /* 11 */
        else
            z = 12; /* 12 */
    }

    if (z) {
        bool ok = false;

        xy.x -= Q->pj[z - 1]->x0;
        xy.y -= Q->pj[z - 1]->y0;
        lp = Q->pj[z - 1]->inv(xy, Q->pj[z - 1]);
        lp.lam += Q->pj[z - 1]->lam0;

        switch (z) {
        case 1:
            ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d40 + EPSLN) ||
                 ((lp.lam >= -d40 - EPSLN && lp.lam <= -d10 + EPSLN) &&
                  (lp.phi >= d60 - EPSLN && lp.phi <= d90 + EPSLN));
            break;
        case 2:
            ok = (lp.lam >= -d40 - EPSLN && lp.lam <= d180 + EPSLN) ||
                 ((lp.lam >= -d180 - EPSLN && lp.lam <= -d160 + EPSLN) &&
                  (lp.phi >= d50 - EPSLN && lp.phi <= d90 + EPSLN)) ||
                 ((lp.lam >= -d50 - EPSLN && lp.lam <= -d40 + EPSLN) &&
                  (lp.phi >= d60 - EPSLN && lp.phi <= d90 + EPSLN));
            break;
        case 3:
            ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d40 + EPSLN);
            break;
        case 4:
            ok = (lp.lam >= -d40 - EPSLN && lp.lam <= d180 + EPSLN);
            break;
        case 5:
            ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d100 + EPSLN);
            break;
        case 6:
            ok = (lp.lam >= -d100 - EPSLN && lp.lam <= -d20 + EPSLN);
            break;
        case 7:
            ok = (lp.lam >= -d20 - EPSLN && lp.lam <= d80 + EPSLN);
            break;
        case 8:
            ok = (lp.lam >= d80 - EPSLN && lp.lam <= d180 + EPSLN);
            break;
        case 9:
            ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d100 + EPSLN);
            break;
        case 10:
            ok = (lp.lam >= -d100 - EPSLN && lp.lam <= -d20 + EPSLN);
            break;
        case 11:
            ok = (lp.lam >= -d20 - EPSLN && lp.lam <= d80 + EPSLN);
            break;
        case 12:
            ok = (lp.lam >= d80 - EPSLN && lp.lam <= d180 + EPSLN);
            break;
        }
        z = (!ok ? 0 : z); /* projectable? */
    }

    if (!z)
        lp.lam = HUGE_VAL;
    if (!z)
        lp.phi = HUGE_VAL;

    return lp;
}

static PJ *pj_igh_data_destructor(PJ *P, int errlev) {
    using namespace pj_igh_ns;
    int i;
    if (nullptr == P)
        return nullptr;

    if (nullptr == P->opaque)
        return pj_default_destructor(P, errlev);

    struct pj_igh_data *Q = static_cast<struct pj_igh_data *>(P->opaque);

    for (i = 0; i < 12; ++i) {
        if (Q->pj[i])
            Q->pj[i]->destructor(Q->pj[i], errlev);
    }

    return pj_default_destructor(P, errlev);
}

/*
  Zones:

    -180            -40                       180
      +--------------+-------------------------+    Zones 1,2,9,10,11 & 12:
      |1             |2                        |      Mollweide projection
      |              |                         |
      +--------------+-------------------------+    Zones 3,4,5,6,7 & 8:
      |3             |4                        |      Sinusoidal projection
      |              |                         |
    0 +-------+------+-+-----------+-----------+
      |5      |6       |7          |8          |
      |       |        |           |           |
      +-------+--------+-----------+-----------+
      |9      |10      |11         |12         |
      |       |        |           |           |
      +-------+--------+-----------+-----------+
    -180    -100      -20         80          180
*/

static bool pj_igh_setup_zone(PJ *P, struct pj_igh_ns::pj_igh_data *Q, int n,
                              PJ *(*proj_ptr)(PJ *), double x_0, double y_0,
                              double lon_0) {
    if (!(Q->pj[n - 1] = proj_ptr(nullptr)))
        return false;
    if (!(Q->pj[n - 1] = proj_ptr(Q->pj[n - 1])))
        return false;
    Q->pj[n - 1]->ctx = P->ctx;
    Q->pj[n - 1]->x0 = x_0;
    Q->pj[n - 1]->y0 = y_0;
    Q->pj[n - 1]->lam0 = lon_0;
    return true;
}

PJ *PJ_PROJECTION(igh) {
    using namespace pj_igh_ns;

    PJ_XY xy1, xy3;
    PJ_LP lp = {0, igh_phi_boundary};
    struct pj_igh_data *Q = static_cast<struct pj_igh_data *>(
        calloc(1, sizeof(struct pj_igh_data)));
    if (nullptr == Q)
        return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    P->opaque = Q;

    /* sinusoidal zones */
    if (!pj_igh_setup_zone(P, Q, 3, pj_sinu, -d100, 0, -d100) ||
        !pj_igh_setup_zone(P, Q, 4, pj_sinu, d30, 0, d30) ||
        !pj_igh_setup_zone(P, Q, 5, pj_sinu, -d160, 0, -d160) ||
        !pj_igh_setup_zone(P, Q, 6, pj_sinu, -d60, 0, -d60) ||
        !pj_igh_setup_zone(P, Q, 7, pj_sinu, d20, 0, d20) ||
        !pj_igh_setup_zone(P, Q, 8, pj_sinu, d140, 0, d140)) {
        return pj_igh_data_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    }

    /* mollweide zones */
    if (!pj_igh_setup_zone(P, Q, 1, pj_moll, -d100, 0, -d100)) {
        return pj_igh_data_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    }

    /* y0 ? */
    xy1 = Q->pj[0]->fwd(lp, Q->pj[0]); /* zone 1 */
    xy3 = Q->pj[2]->fwd(lp, Q->pj[2]); /* zone 3 */
    /* y0 + xy1.y = xy3.y for lt = 40d44'11.8" */
    Q->dy0 = xy3.y - xy1.y;

    Q->pj[0]->y0 = Q->dy0;

    /* mollweide zones (cont'd) */
    if (!pj_igh_setup_zone(P, Q, 2, pj_moll, d30, Q->dy0, d30) ||
        !pj_igh_setup_zone(P, Q, 9, pj_moll, -d160, -Q->dy0, -d160) ||
        !pj_igh_setup_zone(P, Q, 10, pj_moll, -d60, -Q->dy0, -d60) ||
        !pj_igh_setup_zone(P, Q, 11, pj_moll, d20, -Q->dy0, d20) ||
        !pj_igh_setup_zone(P, Q, 12, pj_moll, d140, -Q->dy0, d140)) {
        return pj_igh_data_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    }

    P->inv = igh_s_inverse;
    P->fwd = igh_s_forward;
    P->destructor = pj_igh_data_destructor;
    P->es = 0.;

    return P;
}

Coverage Report

Created: 2026-04-01 06:20

Line	Count	Source
1
2
3		#include <errno.h>
4		#include <math.h>
5
6		#include "proj.h"
7		#include "proj_internal.h"
8
9		PROJ_HEAD(igh, "Interrupted Goode Homolosine") "\n\tPCyl, Sph";
10
11		/*
12		This projection is a compilation of 12 separate sub-projections.
13		Sinusoidal projections are found near the equator and Mollweide
14		projections are found at higher latitudes. The transition between
15		the two occurs at 40 degrees latitude and is represented by the
16		constant `igh_phi_boundary`.
17
18		Each sub-projection is assigned an integer label
19		numbered 1 through 12. Most of this code contains logic to assign
20		the labels based on latitude (phi) and longitude (lam) regions.
21
22		Original Reference:
23		J. Paul Goode (1925) THE HOMOLOSINE PROJECTION: A NEW DEVICE FOR
24		PORTRAYING THE EARTH'S SURFACE ENTIRE, Annals of the Association of
25		American Geographers, 15:3, 119-125, DOI: 10.1080/00045602509356949
26		*/
27
28		C_NAMESPACE PJ pj_sinu(PJ ), pj_moll(PJ );
29
30		/*
31		Transition from sinusoidal to Mollweide projection
32		Latitude (phi): 40deg 44' 11.8"
33		*/
34
35		constexpr double igh_phi_boundary = (40 + 44 / 60. + 11.8 / 3600.) * DEG_TO_RAD;
36
37		namespace pj_igh_ns {
38		struct pj_igh_data {
39		struct PJconsts *pj[12];
40		double dy0;
41		};
42
43		constexpr double d10 = 10 * DEG_TO_RAD;
44		constexpr double d20 = 20 * DEG_TO_RAD;
45		constexpr double d30 = 30 * DEG_TO_RAD;
46		constexpr double d40 = 40 * DEG_TO_RAD;
47		constexpr double d50 = 50 * DEG_TO_RAD;
48		constexpr double d60 = 60 * DEG_TO_RAD;
49		constexpr double d80 = 80 * DEG_TO_RAD;
50		constexpr double d90 = 90 * DEG_TO_RAD;
51		constexpr double d100 = 100 * DEG_TO_RAD;
52		constexpr double d140 = 140 * DEG_TO_RAD;
53		constexpr double d160 = 160 * DEG_TO_RAD;
54		constexpr double d180 = 180 * DEG_TO_RAD;
55
56		constexpr double EPSLN =
57		1.e-10; /* allow a little 'slack' on zone edge positions */
58
59		} // namespace pj_igh_ns
60
61	0	static PJ_XY igh_s_forward(PJ_LP lp, PJ P) { / Spheroidal, forward */
62	0	using namespace pj_igh_ns;
63	0	PJ_XY xy;
64	0	struct pj_igh_data Q = static_cast<struct pj_igh_data >(P->opaque);
65	0	int z;
66
67	0	if (lp.phi >= igh_phi_boundary) { /* 1\|2 */
68	0	z = (lp.lam <= -d40 ? 1 : 2);
69	0	} else if (lp.phi >= 0) { /* 3\|4 */
70	0	z = (lp.lam <= -d40 ? 3 : 4);
71	0	} else if (lp.phi >= -igh_phi_boundary) { /* 5\|6\|7\|8 */
72	0	if (lp.lam <= -d100)
73	0	z = 5; /* 5 */
74	0	else if (lp.lam <= -d20)
75	0	z = 6; /* 6 */
76	0	else if (lp.lam <= d80)
77	0	z = 7; /* 7 */
78	0	else
79	0	z = 8; /* 8 */
80	0	} else { /* 9\|10\|11\|12 */
81	0	if (lp.lam <= -d100)
82	0	z = 9; /* 9 */
83	0	else if (lp.lam <= -d20)
84	0	z = 10; /* 10 */
85	0	else if (lp.lam <= d80)
86	0	z = 11; /* 11 */
87	0	else
88	0	z = 12; /* 12 */
89	0	}
90
91	0	lp.lam -= Q->pj[z - 1]->lam0;
92	0	xy = Q->pj[z - 1]->fwd(lp, Q->pj[z - 1]);
93	0	xy.x += Q->pj[z - 1]->x0;
94	0	xy.y += Q->pj[z - 1]->y0;
95
96	0	return xy;
97	0	}
98
99	0	static PJ_LP igh_s_inverse(PJ_XY xy, PJ P) { / Spheroidal, inverse */
100	0	using namespace pj_igh_ns;
101	0	PJ_LP lp = {0.0, 0.0};
102	0	struct pj_igh_data Q = static_cast<struct pj_igh_data >(P->opaque);
103	0	const double y90 =
104	0	Q->dy0 + sqrt(2.0); /* lt=90 corresponds to y=y0+sqrt(2) */
105
106	0	int z = 0;
107	0	if (xy.y > y90 + EPSLN \|\| xy.y < -y90 + EPSLN) /* 0 */
108	0	z = 0;
109	0	else if (xy.y >= igh_phi_boundary) /* 1\|2 */
110	0	z = (xy.x <= -d40 ? 1 : 2);
111	0	else if (xy.y >= 0) /* 3\|4 */
112	0	z = (xy.x <= -d40 ? 3 : 4);
113	0	else if (xy.y >= -igh_phi_boundary) { /* 5\|6\|7\|8 */
114	0	if (xy.x <= -d100)
115	0	z = 5; /* 5 */
116	0	else if (xy.x <= -d20)
117	0	z = 6; /* 6 */
118	0	else if (xy.x <= d80)
119	0	z = 7; /* 7 */
120	0	else
121	0	z = 8; /* 8 */
122	0	} else { /* 9\|10\|11\|12 */
123	0	if (xy.x <= -d100)
124	0	z = 9; /* 9 */
125	0	else if (xy.x <= -d20)
126	0	z = 10; /* 10 */
127	0	else if (xy.x <= d80)
128	0	z = 11; /* 11 */
129	0	else
130	0	z = 12; /* 12 */
131	0	}
132
133	0	if (z) {
134	0	bool ok = false;
135
136	0	xy.x -= Q->pj[z - 1]->x0;
137	0	xy.y -= Q->pj[z - 1]->y0;
138	0	lp = Q->pj[z - 1]->inv(xy, Q->pj[z - 1]);
139	0	lp.lam += Q->pj[z - 1]->lam0;
140
141	0	switch (z) {
142	0	case 1:
143	0	ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d40 + EPSLN) \|\|
144	0	((lp.lam >= -d40 - EPSLN && lp.lam <= -d10 + EPSLN) &&
145	0	(lp.phi >= d60 - EPSLN && lp.phi <= d90 + EPSLN));
146	0	break;
147	0	case 2:
148	0	ok = (lp.lam >= -d40 - EPSLN && lp.lam <= d180 + EPSLN) \|\|
149	0	((lp.lam >= -d180 - EPSLN && lp.lam <= -d160 + EPSLN) &&
150	0	(lp.phi >= d50 - EPSLN && lp.phi <= d90 + EPSLN)) \|\|
151	0	((lp.lam >= -d50 - EPSLN && lp.lam <= -d40 + EPSLN) &&
152	0	(lp.phi >= d60 - EPSLN && lp.phi <= d90 + EPSLN));
153	0	break;
154	0	case 3:
155	0	ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d40 + EPSLN);
156	0	break;
157	0	case 4:
158	0	ok = (lp.lam >= -d40 - EPSLN && lp.lam <= d180 + EPSLN);
159	0	break;
160	0	case 5:
161	0	ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d100 + EPSLN);
162	0	break;
163	0	case 6:
164	0	ok = (lp.lam >= -d100 - EPSLN && lp.lam <= -d20 + EPSLN);
165	0	break;
166	0	case 7:
167	0	ok = (lp.lam >= -d20 - EPSLN && lp.lam <= d80 + EPSLN);
168	0	break;
169	0	case 8:
170	0	ok = (lp.lam >= d80 - EPSLN && lp.lam <= d180 + EPSLN);
171	0	break;
172	0	case 9:
173	0	ok = (lp.lam >= -d180 - EPSLN && lp.lam <= -d100 + EPSLN);
174	0	break;
175	0	case 10:
176	0	ok = (lp.lam >= -d100 - EPSLN && lp.lam <= -d20 + EPSLN);
177	0	break;
178	0	case 11:
179	0	ok = (lp.lam >= -d20 - EPSLN && lp.lam <= d80 + EPSLN);
180	0	break;
181	0	case 12:
182	0	ok = (lp.lam >= d80 - EPSLN && lp.lam <= d180 + EPSLN);
183	0	break;
184	0	}
185	0	z = (!ok ? 0 : z); /* projectable? */
186	0	}
187
188	0	if (!z)
189	0	lp.lam = HUGE_VAL;
190	0	if (!z)
191	0	lp.phi = HUGE_VAL;
192
193	0	return lp;
194	0	}
195
196	12	static PJ pj_igh_data_destructor(PJ P, int errlev) {
197	12	using namespace pj_igh_ns;
198	12	int i;
199	12	if (nullptr == P)
200	0	return nullptr;
201
202	12	if (nullptr == P->opaque)
203	0	return pj_default_destructor(P, errlev);
204
205	12	struct pj_igh_data Q = static_cast<struct pj_igh_data >(P->opaque);
206
207	156	for (i = 0; i < 12; ++i) {
208	144	if (Q->pj[i])
209	144	Q->pj[i]->destructor(Q->pj[i], errlev);
210	144	}
211
212	12	return pj_default_destructor(P, errlev);
213	12	}
214
215		/*
216		Zones:
217
218		-180 -40 180
219		+--------------+-------------------------+ Zones 1,2,9,10,11 & 12:
220		\|1 \|2 \| Mollweide projection
221		\| \| \|
222		+--------------+-------------------------+ Zones 3,4,5,6,7 & 8:
223		\|3 \|4 \| Sinusoidal projection
224		\| \| \|
225		0 +-------+------+-+-----------+-----------+
226		\|5 \|6 \|7 \|8 \|
227		\| \| \| \| \|
228		+-------+--------+-----------+-----------+
229		\|9 \|10 \|11 \|12 \|
230		\| \| \| \| \|
231		+-------+--------+-----------+-----------+
232		-180 -100 -20 80 180
233		*/
234
235		static bool pj_igh_setup_zone(PJ P, struct pj_igh_ns::pj_igh_data Q, int n,
236		PJ (proj_ptr)(PJ *), double x_0, double y_0,
237	144	double lon_0) {
238	144	if (!(Q->pj[n - 1] = proj_ptr(nullptr)))
239	0	return false;
240	144	if (!(Q->pj[n - 1] = proj_ptr(Q->pj[n - 1])))
241	0	return false;
242	144	Q->pj[n - 1]->ctx = P->ctx;
243	144	Q->pj[n - 1]->x0 = x_0;
244	144	Q->pj[n - 1]->y0 = y_0;
245	144	Q->pj[n - 1]->lam0 = lon_0;
246	144	return true;
247	144	}
248
249	12	PJ *PJ_PROJECTION(igh) {
250	12	using namespace pj_igh_ns;
251
252	12	PJ_XY xy1, xy3;
253	12	PJ_LP lp = {0, igh_phi_boundary};
254	12	struct pj_igh_data Q = static_cast<struct pj_igh_data >(
255	12	calloc(1, sizeof(struct pj_igh_data)));
256	12	if (nullptr == Q)
257	0	return pj_default_destructor(P, PROJ_ERR_OTHER /ENOMEM/);
258	12	P->opaque = Q;
259
260		/* sinusoidal zones */
261	12	if (!pj_igh_setup_zone(P, Q, 3, pj_sinu, -d100, 0, -d100) \|\|
262	12	!pj_igh_setup_zone(P, Q, 4, pj_sinu, d30, 0, d30) \|\|
263	12	!pj_igh_setup_zone(P, Q, 5, pj_sinu, -d160, 0, -d160) \|\|
264	12	!pj_igh_setup_zone(P, Q, 6, pj_sinu, -d60, 0, -d60) \|\|
265	12	!pj_igh_setup_zone(P, Q, 7, pj_sinu, d20, 0, d20) \|\|
266	12	!pj_igh_setup_zone(P, Q, 8, pj_sinu, d140, 0, d140)) {
267	0	return pj_igh_data_destructor(P, PROJ_ERR_OTHER /ENOMEM/);
268	0	}
269
270		/* mollweide zones */
271	12	if (!pj_igh_setup_zone(P, Q, 1, pj_moll, -d100, 0, -d100)) {
272	0	return pj_igh_data_destructor(P, PROJ_ERR_OTHER /ENOMEM/);
273	0	}
274
275		/* y0 ? */
276	12	xy1 = Q->pj[0]->fwd(lp, Q->pj[0]); /* zone 1 */
277	12	xy3 = Q->pj[2]->fwd(lp, Q->pj[2]); /* zone 3 */
278		/* y0 + xy1.y = xy3.y for lt = 40d44'11.8" */
279	12	Q->dy0 = xy3.y - xy1.y;
280
281	12	Q->pj[0]->y0 = Q->dy0;
282
283		/* mollweide zones (cont'd) */
284	12	if (!pj_igh_setup_zone(P, Q, 2, pj_moll, d30, Q->dy0, d30) \|\|
285	12	!pj_igh_setup_zone(P, Q, 9, pj_moll, -d160, -Q->dy0, -d160) \|\|
286	12	!pj_igh_setup_zone(P, Q, 10, pj_moll, -d60, -Q->dy0, -d60) \|\|
287	12	!pj_igh_setup_zone(P, Q, 11, pj_moll, d20, -Q->dy0, d20) \|\|
288	12	!pj_igh_setup_zone(P, Q, 12, pj_moll, d140, -Q->dy0, d140)) {
289	0	return pj_igh_data_destructor(P, PROJ_ERR_OTHER /ENOMEM/);
290	0	}
291
292	12	P->inv = igh_s_inverse;
293	12	P->fwd = igh_s_forward;
294	12	P->destructor = pj_igh_data_destructor;
295	12	P->es = 0.;
296
297	12	return P;
298	12	}