PROJ *
proj_init(int argc, char **argv) {
const char *s, *name;
PROJ *(*proj)(PROJ *);
paralist *curr = 0, *start = 0;
int i;
PROJ *PIN = 0;
errno = proj_errno = 0;
/* put arguments into internal linked list */
if (argc <= 0) { proj_errno = -1; goto bum_call; }
for (i = 0; i < argc; ++i)
if (i)
curr = curr->next = proj_mkparam(argv[i]);
else
start = curr = proj_mkparam(argv[i]);
if (proj_errno) goto bum_call;
/* find projection selection */
if (!(name = proj_param(start, "sproj").s))
{ proj_errno = -4; goto bum_call; }
for (i = 0; (s = proj_list[i].id) && strcmp(name, s) ; ++i) ;
if (!s) { proj_errno = -5; goto bum_call; }
proj = proj_list[i].proj;
/* allocate projection structure */
if (!(PIN = (*proj)(0))) goto bum_call;
PIN->params = start;
/* set ellipsoid/sphere parameters */
if (proj_ell_set(start, &PIN->a, &PIN->es)) goto bum_call;
PIN->e = sqrt(PIN->es);
PIN->ra = 1. / PIN->a;
PIN->one_es = 1. - PIN->es;
if (PIN->one_es == 0.) { proj_errno = -6; goto bum_call; }
PIN->rone_es = 1./PIN->one_es;
/* set PIN->geoc coordinate system */
PIN->geoc = (PIN->es && proj_param(start, "bgeoc").i);
/* over-ranging flag */
PIN->over = proj_param(start, "bover").i;
/* central meridian */
PIN->lam0=proj_param(start, "rlon_0").f;
/* central latitude */
PIN->phi0 = proj_param(start, "rlat_0").f;
/* false easting and northing */
PIN->x0 = proj_param(start, "dx_0").f;
PIN->y0 = proj_param(start, "dy_0").f;
/* general scaling factor */
if (proj_param(start, "tk_0").i)
PIN->k0 = proj_param(start, "dk_0").f;
else if (proj_param(start, "tk").i)
PIN->k0 = proj_param(start, "dk").f;
else
PIN->k0 = 1.;
if (PIN->k0 <= 0.) {
proj_errno = -31;
goto bum_call;
}
/* set units */
s = 0;
if ((name = proj_param(start, "sunits").s)) {
for (i = 0; (s = proj_units[i].id) && strcmp(name, s) ; ++i) ;
if (!s) { proj_errno = -7; goto bum_call; }
s = proj_units[i].to_meter;
}
if (s || (s = proj_param(start, "sto_meter").s)) {
PIN->to_meter = strtod(s, (char **)&s);
if (*s == '/') /* ratio number */
PIN->to_meter /= strtod(++s, 0);
PIN->fr_meter = 1. / PIN->to_meter;
} else
PIN->to_meter = PIN->fr_meter = 1.;
/* projection specific initialization */
if (!(PIN = (*proj)(PIN)) || errno || proj_errno) {
bum_call: /* cleanup error return */
if (!proj_errno)
proj_errno = errno;
if (PIN)
proj_free(PIN);
else
for ( ; start; start = curr) {
curr = start->next;
free(start);
}
PIN = 0;
}
return PIN;
}
/*
** set ellipsoid parameters
*/
#include <lib_proj.h>
#include <string.h>
#define SIXTH .1666666666666666667 /* 1/6 */
#define RA4 .04722222222222222222 /* 17/360 */
#define RA6 .02215608465608465608 /* 67/3024 */
#define RV4 .06944444444444444444 /* 5/72 */
#define RV6 .04243827160493827160 /* 55/1296 */
int /* initialize geographic shape parameters */
proj_ell_set(paralist *pl, double *a, double *es) {
int i;
double b = 0., e;
const char *name;
paralist *start = 0, *curr;
/* check for varying forms of ellipsoid input */
*a = *es = 0.;
/* R takes precedence */
if (proj_param(pl, "tR").i)
*a = proj_param(pl, "dR").f;
else { /* probable elliptical figure */
/* check if ellps present and temporarily append its values to pl */
if ((name = proj_param(pl, "sellps").s)) {
char *s;
for (start = pl; start && start->next ; start = start->next) ;
curr = start;
for (i = 0; (s = proj_ellps[i].id) && strcmp(name, s) ; ++i) ;
if (!s) {
proj_errno = -9;
return 1;
}
curr = curr->next = proj_mkparam(proj_ellps[i].major);
curr = curr->next = proj_mkparam(proj_ellps[i].ell);
}
/* set major axis to unity if not spec'd */
*a = (proj_param(pl, "ta").i) ? proj_param(pl, "da").f : 1.;
if (proj_param(pl, "tes").i) /* eccentricity squared */
*es = proj_param(pl, "des").f;
else if (proj_param(pl, "te").i) { /* eccentricity */
e = proj_param(pl, "de").f;
*es = e * e;
} else if (proj_param(pl, "trf").i) { /* recip flattening */
*es = proj_param(pl, "drf").f;
if (!*es) {
proj_errno = -10;
goto bomb;
}
*es = 1./ *es;
*es = *es * (2. - *es);
} else if (proj_param(pl, "tf").i) { /* flattening */
*es = proj_param(pl, "df").f;
*es = *es * (2. - *es);
} else if (proj_param(pl, "tb").i) { /* minor axis */
b = proj_param(pl, "db").f;
*es = 1. - (b * b) / (*a * *a);
} /* else *es == 0. and sphere of radius *a */
if (!b)
b = *a * sqrt(1. - *es);
/* following options turn ellipsoid into equivalent sphere */
if (proj_param(pl, "bR_A").i) { /* sphere--area of ellipsoid */
*a *= 1. - *es * (SIXTH + *es * (RA4 + *es * RA6));
*es = 0.;
} else if (proj_param(pl, "bR_V").i) { /* sphere--vol. of ellipsoid */
*a *= 1. - *es * (SIXTH + *es * (RV4 + *es * RV6));
*es = 0.;
} else if (proj_param(pl, "bR_a").i) { /* sphere--arithmetic mean */
*a = .5 * (*a + b);
*es = 0.;
} else if (proj_param(pl, "bR_g").i) { /* sphere--geometric mean */
*a = sqrt(*a * b);
*es = 0.;
} else if (proj_param(pl, "bR_h").i) { /* sphere--harmonic mean */
*a = 2. * *a * b / (*a + b);
*es = 0.;
} else if ((i = proj_param(pl, "tR_lat_a").i) || /* sphere--arith. */
proj_param(pl, "tR_lat_g").i) { /* or geom. mean at latitude */
double tmp;
tmp = sin(proj_param(pl, i ? "rR_lat_a" : "rR_lat_g").f);
if (fabs(tmp) > HALFPI) {
proj_errno = -11;
goto bomb;
}
tmp = 1. - *es * tmp * tmp;
*a *= i ? .5 * (1. - *es + tmp) / ( tmp * sqrt(tmp)) :
sqrt(1. - *es) / tmp;
*es = 0.;
}
bomb:
if (start) { /* clean up temporary extension of list */
free(start->next->next);
free(start->next);
start->next = 0;
}
if (proj_errno)
return 1;
}
/* some remaining checks */
if (*es < 0.)
{
proj_errno = -12;
return 1;
}
if (*a <= 0.)
{
proj_errno = -13;
return 1;
}
return 0;
}
