proj/src/PJ_hammer.c

   1 #define PROJ_PARMS__ \
   2         double w; \
   3         double m, rm;
   4 #define PJ_LIB__
   5 # include       <projects.h>
   6 PROJ_HEAD(hammer, "Hammer & Eckert-Greifendorff")
   7         "\n\tMisc Sph, no inv.\n\tW= M=";
   8 FORWARD(s_forward); /* spheroid */
   9         double cosphi, d;
  10
  11         d = sqrt(2./(1. + (cosphi = cos(lp.phi)) * cos(lp.lam *= P->w)));
  12         xy.x = P->m * d * cosphi * sin(lp.lam);
  13         xy.y = P->rm * d * sin(lp.phi);
  14         return (xy);
  15 }
  16 FREEUP; if (P) pj_dalloc(P); }
  17 ENTRY0(hammer)
  18         if (pj_param(P->ctx, P->params, "tW").i) {
  19                 if ((P->w = fabs(pj_param(P->ctx, P->params, "dW").f)) <= 0.) E_ERROR(-27);
  20         } else
  21                 P->w = .5;
  22         if (pj_param(P->ctx, P->params, "tM").i) {
  23                 if ((P->m = fabs(pj_param(P->ctx, P->params, "dM").f)) <= 0.) E_ERROR(-27);
  24         } else
  25                 P->m = 1.;
  26         P->rm = 1. / P->m;
  27         P->m /= P->w;
  28         P->es = 0.; P->fwd = s_forward;
  29 ENDENTRY(P)