diff options
Diffstat (limited to 'src/projections/sconics.cpp')
| -rw-r--r-- | src/projections/sconics.cpp | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/src/projections/sconics.cpp b/src/projections/sconics.cpp new file mode 100644 index 00000000..1d19a13d --- /dev/null +++ b/src/projections/sconics.cpp @@ -0,0 +1,220 @@ +#define PJ_LIB__ +#include <errno.h> +#include "proj.h" +#include "projects.h" +#include "proj_math.h" + + +namespace { // anonymous namespace +enum Type { + EULER = 0, + MURD1 = 1, + MURD2 = 2, + MURD3 = 3, + PCONIC = 4, + TISSOT = 5, + VITK1 = 6 +}; +} // anonymous namespace + +namespace { // anonymous namespace +struct pj_opaque { + double n; + double rho_c; + double rho_0; + double sig; + double c1, c2; + enum Type type; +}; +} // anonymous namespace + + +#define EPS10 1.e-10 +#define EPS 1e-10 +#define LINE2 "\n\tConic, Sph\n\tlat_1= and lat_2=" + +PROJ_HEAD(euler, "Euler") LINE2; +PROJ_HEAD(murd1, "Murdoch I") LINE2; +PROJ_HEAD(murd2, "Murdoch II") LINE2; +PROJ_HEAD(murd3, "Murdoch III") LINE2; +PROJ_HEAD(pconic, "Perspective Conic") LINE2; +PROJ_HEAD(tissot, "Tissot") LINE2; +PROJ_HEAD(vitk1, "Vitkovsky I") LINE2; + + + +/* get common factors for simple conics */ +static int phi12(PJ *P, double *del) { + double p1, p2; + int err = 0; + + if (!pj_param(P->ctx, P->params, "tlat_1").i || + !pj_param(P->ctx, P->params, "tlat_2").i) { + err = -41; + } else { + p1 = pj_param(P->ctx, P->params, "rlat_1").f; + p2 = pj_param(P->ctx, P->params, "rlat_2").f; + *del = 0.5 * (p2 - p1); + static_cast<struct pj_opaque*>(P->opaque)->sig = 0.5 * (p2 + p1); + err = (fabs(*del) < EPS || fabs(static_cast<struct pj_opaque*>(P->opaque)->sig) < EPS) ? PJD_ERR_ABS_LAT1_EQ_ABS_LAT2 : 0; + } + return err; +} + + +static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */ + XY xy = {0.0, 0.0}; + struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque); + double rho; + + switch (Q->type) { + case MURD2: + rho = Q->rho_c + tan (Q->sig - lp.phi); + break; + case PCONIC: + rho = Q->c2 * (Q->c1 - tan (lp.phi - Q->sig)); + break; + default: + rho = Q->rho_c - lp.phi; + break; + } + + xy.x = rho * sin ( lp.lam *= Q->n ); + xy.y = Q->rho_0 - rho * cos (lp.lam); + return xy; +} + + +static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, (and ellipsoidal?) inverse */ + LP lp = {0.0, 0.0}; + struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque); + double rho; + + rho = hypot (xy.x, xy.y = Q->rho_0 - xy.y); + if (Q->n < 0.) { + rho = - rho; + xy.x = - xy.x; + xy.y = - xy.y; + } + + lp.lam = atan2 (xy.x, xy.y) / Q->n; + + switch (Q->type) { + case PCONIC: + lp.phi = atan (Q->c1 - rho / Q->c2) + Q->sig; + break; + case MURD2: + lp.phi = Q->sig - atan(rho - Q->rho_c); + break; + default: + lp.phi = Q->rho_c - rho; + } + return lp; +} + + +static PJ *setup(PJ *P, enum Type type) { + double del, cs; + int err; + struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque))); + if (nullptr==Q) + return pj_default_destructor (P, ENOMEM); + P->opaque = Q; + Q->type = type; + + err = phi12 (P, &del); + if(err) + return pj_default_destructor (P, err); + + switch (Q->type) { + + case TISSOT: + Q->n = sin (Q->sig); + cs = cos (del); + Q->rho_c = Q->n / cs + cs / Q->n; + Q->rho_0 = sqrt ((Q->rho_c - 2 * sin (P->phi0)) / Q->n); + break; + + case MURD1: + Q->rho_c = sin(del)/(del * tan(Q->sig)) + Q->sig; + Q->rho_0 = Q->rho_c - P->phi0; + Q->n = sin(Q->sig); + break; + + case MURD2: + Q->rho_c = (cs = sqrt (cos (del))) / tan (Q->sig); + Q->rho_0 = Q->rho_c + tan (Q->sig - P->phi0); + Q->n = sin (Q->sig) * cs; + break; + + case MURD3: + Q->rho_c = del / (tan(Q->sig) * tan(del)) + Q->sig; + Q->rho_0 = Q->rho_c - P->phi0; + Q->n = sin (Q->sig) * sin (del) * tan (del) / (del * del); + break; + + case EULER: + Q->n = sin (Q->sig) * sin (del) / del; + del *= 0.5; + Q->rho_c = del / (tan (del) * tan (Q->sig)) + Q->sig; + Q->rho_0 = Q->rho_c - P->phi0; + break; + + case PCONIC: + Q->n = sin (Q->sig); + Q->c2 = cos (del); + Q->c1 = 1./tan (Q->sig); + if (fabs (del = P->phi0 - Q->sig) - EPS10 >= M_HALFPI) + return pj_default_destructor(P, PJD_ERR_LAT_0_HALF_PI_FROM_MEAN); + + Q->rho_0 = Q->c2 * (Q->c1 - tan (del)); + break; + + case VITK1: + Q->n = (cs = tan (del)) * sin (Q->sig) / del; + Q->rho_c = del / (cs * tan (Q->sig)) + Q->sig; + Q->rho_0 = Q->rho_c - P->phi0; + break; + } + + P->inv = s_inverse; + P->fwd = s_forward; + P->es = 0; + return (P); +} + + +PJ *PROJECTION(euler) { + return setup(P, EULER); +} + + +PJ *PROJECTION(tissot) { + return setup(P, TISSOT); +} + + +PJ *PROJECTION(murd1) { + return setup(P, MURD1); +} + + +PJ *PROJECTION(murd2) { + return setup(P, MURD2); +} + + +PJ *PROJECTION(murd3) { + return setup(P, MURD3); +} + + +PJ *PROJECTION(pconic) { + return setup(P, PCONIC); +} + + +PJ *PROJECTION(vitk1) { + return setup(P, VITK1); +} + |