diff options
Diffstat (limited to 'src/PJ_eck4.c')
| -rw-r--r-- | src/PJ_eck4.c | 234 |
1 files changed, 117 insertions, 117 deletions
diff --git a/src/PJ_eck4.c b/src/PJ_eck4.c index 8a56f019..66eaa9d0 100644 --- a/src/PJ_eck4.c +++ b/src/PJ_eck4.c @@ -1,117 +1,117 @@ -#define PJ_LIB__
-#include <projects.h>
-
-PROJ_HEAD(eck4, "Eckert IV") "\n\tPCyl, Sph.";
-
-#define C_x .42223820031577120149
-#define C_y 1.32650042817700232218
-#define RC_y .75386330736002178205
-#define C_p 3.57079632679489661922
-#define RC_p .28004957675577868795
-#define EPS 1e-7
-#define NITER 6
-
-
-static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */
- XY xy = {0.0,0.0};
- double p, V, s, c;
- int i;
- (void) P;
-
- p = C_p * sin(lp.phi);
- V = lp.phi * lp.phi;
- lp.phi *= 0.895168 + V * ( 0.0218849 + V * 0.00826809 );
- for (i = NITER; i ; --i) {
- c = cos(lp.phi);
- s = sin(lp.phi);
- lp.phi -= V = (lp.phi + s * (c + 2.) - p) /
- (1. + c * (c + 2.) - s * s);
- if (fabs(V) < EPS)
- break;
- }
- if (!i) {
- xy.x = C_x * lp.lam;
- xy.y = lp.phi < 0. ? -C_y : C_y;
- } else {
- xy.x = C_x * lp.lam * (1. + cos(lp.phi));
- xy.y = C_y * sin(lp.phi);
- }
- return xy;
-}
-
-
-static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */
- LP lp = {0.0,0.0};
- double c;
-
- lp.phi = aasin(P->ctx,xy.y / C_y);
- lp.lam = xy.x / (C_x * (1. + (c = cos(lp.phi))));
- lp.phi = aasin(P->ctx,(lp.phi + sin(lp.phi) * (c + 2.)) / C_p);
- return lp;
-}
-
-
-static void *freeup_new (PJ *P) { /* Destructor */
- if (0==P)
- return 0;
- return pj_dealloc(P);
-}
-
-static void freeup (PJ *P) {
- freeup_new (P);
- return;
-}
-
-
-PJ *PROJECTION(eck4) {
- P->es = 0.0;
- P->inv = s_inverse;
- P->fwd = s_forward;
-
- return P;
-}
-
-
-#ifdef PJ_OMIT_SELFTEST
-int pj_eck4_selftest (void) {return 0;}
-#else
-
-int pj_eck4_selftest (void) {
- double tolerance_lp = 1e-10;
- double tolerance_xy = 1e-7;
-
- char s_args[] = {"+proj=eck4 +a=6400000 +lat_1=0.5 +lat_2=2"};
-
- LP fwd_in[] = {
- { 2, 1},
- { 2,-1},
- {-2, 1},
- {-2,-1}
- };
-
- XY s_fwd_expect[] = {
- { 188646.38935641639, 132268.54017406539},
- { 188646.38935641639, -132268.54017406539},
- {-188646.38935641639, 132268.54017406539},
- {-188646.38935641639, -132268.54017406539},
- };
-
- XY inv_in[] = {
- { 200, 100},
- { 200,-100},
- {-200, 100},
- {-200,-100}
- };
-
- LP s_inv_expect[] = {
- { 0.0021202405520236059, 0.00075601458836610643},
- { 0.0021202405520236059, -0.00075601458836610643},
- {-0.0021202405520236059, 0.00075601458836610643},
- {-0.0021202405520236059, -0.00075601458836610643},
- };
-
- return pj_generic_selftest (0, s_args, tolerance_xy, tolerance_lp, 4, 4, fwd_in, 0, s_fwd_expect, inv_in, 0, s_inv_expect);
-}
-
-
-#endif
+#define PJ_LIB__ +#include <projects.h> + +PROJ_HEAD(eck4, "Eckert IV") "\n\tPCyl, Sph."; + +#define C_x .42223820031577120149 +#define C_y 1.32650042817700232218 +#define RC_y .75386330736002178205 +#define C_p 3.57079632679489661922 +#define RC_p .28004957675577868795 +#define EPS 1e-7 +#define NITER 6 + + +static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */ + XY xy = {0.0,0.0}; + double p, V, s, c; + int i; + (void) P; + + p = C_p * sin(lp.phi); + V = lp.phi * lp.phi; + lp.phi *= 0.895168 + V * ( 0.0218849 + V * 0.00826809 ); + for (i = NITER; i ; --i) { + c = cos(lp.phi); + s = sin(lp.phi); + lp.phi -= V = (lp.phi + s * (c + 2.) - p) / + (1. + c * (c + 2.) - s * s); + if (fabs(V) < EPS) + break; + } + if (!i) { + xy.x = C_x * lp.lam; + xy.y = lp.phi < 0. ? -C_y : C_y; + } else { + xy.x = C_x * lp.lam * (1. + cos(lp.phi)); + xy.y = C_y * sin(lp.phi); + } + return xy; +} + + +static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */ + LP lp = {0.0,0.0}; + double c; + + lp.phi = aasin(P->ctx,xy.y / C_y); + lp.lam = xy.x / (C_x * (1. + (c = cos(lp.phi)))); + lp.phi = aasin(P->ctx,(lp.phi + sin(lp.phi) * (c + 2.)) / C_p); + return lp; +} + + +static void *freeup_new (PJ *P) { /* Destructor */ + if (0==P) + return 0; + return pj_dealloc(P); +} + +static void freeup (PJ *P) { + freeup_new (P); + return; +} + + +PJ *PROJECTION(eck4) { + P->es = 0.0; + P->inv = s_inverse; + P->fwd = s_forward; + + return P; +} + + +#ifdef PJ_OMIT_SELFTEST +int pj_eck4_selftest (void) {return 0;} +#else + +int pj_eck4_selftest (void) { + double tolerance_lp = 1e-10; + double tolerance_xy = 1e-7; + + char s_args[] = {"+proj=eck4 +a=6400000 +lat_1=0.5 +lat_2=2"}; + + LP fwd_in[] = { + { 2, 1}, + { 2,-1}, + {-2, 1}, + {-2,-1} + }; + + XY s_fwd_expect[] = { + { 188646.38935641639, 132268.54017406539}, + { 188646.38935641639, -132268.54017406539}, + {-188646.38935641639, 132268.54017406539}, + {-188646.38935641639, -132268.54017406539}, + }; + + XY inv_in[] = { + { 200, 100}, + { 200,-100}, + {-200, 100}, + {-200,-100} + }; + + LP s_inv_expect[] = { + { 0.0021202405520236059, 0.00075601458836610643}, + { 0.0021202405520236059, -0.00075601458836610643}, + {-0.0021202405520236059, 0.00075601458836610643}, + {-0.0021202405520236059, -0.00075601458836610643}, + }; + + return pj_generic_selftest (0, s_args, tolerance_xy, tolerance_lp, 4, 4, fwd_in, 0, s_fwd_expect, inv_in, 0, s_inv_expect); +} + + +#endif |