ttrapezoidal.c - plan9port - [fork] Plan 9 from user space
  HTML git clone git://src.adamsgaard.dk/plan9port
   DIR Log
   DIR Files
   DIR Refs
   DIR README
   DIR LICENSE
       ---
       ttrapezoidal.c (578B)
       ---
            1 #include <u.h>
            2 #include <libc.h>
            3 #include "map.h"
            4 
            5 static struct coord stdpar0, stdpar1;
            6 static double k;
            7 static double yeq;
            8 
            9 static int
           10 Xtrapezoidal(struct place *place, double *x, double *y)
           11 {
           12         *y = yeq + place->nlat.l;
           13         *x = *y*k*place->wlon.l;
           14         return 1;
           15 }
           16 
           17 proj
           18 trapezoidal(double par0, double par1)
           19 {
           20         if(fabs(fabs(par0)-fabs(par1))<.1)
           21                 return rectangular(par0);
           22         deg2rad(par0,&stdpar0);
           23         deg2rad(par1,&stdpar1);
           24         if(fabs(par1-par0) < .1)
           25                 k = stdpar1.s;
           26         else
           27                 k = (stdpar1.c-stdpar0.c)/(stdpar0.l-stdpar1.l);
           28         yeq = -stdpar1.l - stdpar1.c/k;
           29         return Xtrapezoidal;
           30 }