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#define PROJ_PARMS__ \
struct PJconsts* pj[12]; \
double dy0;
#define PJ_LIB__
#include <projects.h>
PROJ_HEAD(igh, "Interrupted Goode Homolosine") "\n\tPCyl, Sph.";
C_NAMESPACE PJ
*pj_sinu(PJ *), *pj_moll(PJ *);
static const double d4044118 = (40 + 44/60. + 11.8/3600.) * DEG_TO_RAD; // 40d 44' 11.8" [degrees]
static const double d10 = 10 * DEG_TO_RAD;
static const double d20 = 20 * DEG_TO_RAD;
static const double d30 = 30 * DEG_TO_RAD;
static const double d40 = 40 * DEG_TO_RAD;
static const double d50 = 50 * DEG_TO_RAD;
static const double d60 = 60 * DEG_TO_RAD;
static const double d80 = 80 * DEG_TO_RAD;
static const double d90 = 90 * DEG_TO_RAD;
static const double d100 = 100 * DEG_TO_RAD;
static const double d140 = 140 * DEG_TO_RAD;
static const double d160 = 160 * DEG_TO_RAD;
static const double d180 = 180 * DEG_TO_RAD;
static const double EPSLN = 1.e-10; // allow a little 'slack' on zone edge positions
FORWARD(s_forward); /* spheroid */
int z;
if (lp.phi >= d4044118) { // 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 >= -d4044118) { // 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 -= P->pj[z-1]->lam0;
xy = P->pj[z-1]->fwd(lp, P->pj[z-1]);
xy.x += P->pj[z-1]->x0;
xy.y += P->pj[z-1]->y0;
return (xy);
}
INVERSE(s_inverse); /* spheroid */
const double y90 = P->dy0 + sqrt(2); // 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 >= d4044118) // 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 >= -d4044118) { // 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)
{
int ok = 0;
xy.x -= P->pj[z-1]->x0;
xy.y -= P->pj[z-1]->y0;
lp = P->pj[z-1]->inv(xy, P->pj[z-1]);
lp.lam += P->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) pj_errno = -15; // invalid x or y
if (!z) lp.lam = HUGE_VAL;
if (!z) lp.phi = HUGE_VAL;
return (lp);
}
FREEUP;
if (P) {
int i;
for (i = 0; i < 12; ++i)
{
if (P->pj[i])
(*(P->pj[i]->pfree))(P->pj[i]);
}
pj_dalloc(P);
}
}
ENTRY0(igh)
/*
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
*/
#define SETUP(n, proj, x_0, y_0, lon_0) \
if (!(P->pj[n-1] = pj_##proj(0))) E_ERROR_0; \
if (!(P->pj[n-1] = pj_##proj(P->pj[n-1]))) E_ERROR_0; \
P->pj[n-1]->x0 = x_0; \
P->pj[n-1]->y0 = y_0; \
P->pj[n-1]->lam0 = lon_0;
LP lp = { 0, d4044118 };
XY xy1;
XY xy3;
// sinusoidal zones
SETUP(3, sinu, -d100, 0, -d100);
SETUP(4, sinu, d30, 0, d30);
SETUP(5, sinu, -d160, 0, -d160);
SETUP(6, sinu, -d60, 0, -d60);
SETUP(7, sinu, d20, 0, d20);
SETUP(8, sinu, d140, 0, d140);
// mollweide zones
SETUP(1, moll, -d100, 0, -d100);
// y0 ?
xy1 = P->pj[0]->fwd(lp, P->pj[0]); // zone 1
xy3 = P->pj[2]->fwd(lp, P->pj[2]); // zone 3
// y0 + xy1.y = xy3.y for lt = 40d44'11.8"
P->dy0 = xy3.y - xy1.y;
P->pj[0]->y0 = P->dy0;
// mollweide zones (cont'd)
SETUP( 2, moll, d30, P->dy0, d30);
SETUP( 9, moll, -d160, -P->dy0, -d160);
SETUP(10, moll, -d60, -P->dy0, -d60);
SETUP(11, moll, d20, -P->dy0, d20);
SETUP(12, moll, d140, -P->dy0, d140);
P->inv = s_inverse;
P->fwd = s_forward;
P->es = 0.;
ENDENTRY(P)
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