tsimpleconic.c - plan9port - [fork] Plan 9 from user space
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       ---
       tsimpleconic.c (644B)
       ---
            1 #include <u.h>
            2 #include <libc.h>
            3 #include "map.h"
            4 
            5 static double r0, a;
            6 
            7 static int
            8 Xsimpleconic(struct place *place, double *x, double *y)
            9 {
           10         double r = r0 - place->nlat.l;
           11         double t = a*place->wlon.l;
           12         *x = -r*sin(t);
           13         *y = -r*cos(t);
           14         return 1;
           15 }
           16 
           17 proj
           18 simpleconic(double par0, double par1)
           19 {
           20         struct coord lat0;
           21         struct coord lat1;
           22         deg2rad(par0,&lat0);
           23         deg2rad(par1,&lat1);
           24         if(fabs(lat0.l+lat1.l)<.01)
           25                 return rectangular(par0);
           26         if(fabs(lat0.l-lat1.l)<.01) {
           27                 a = lat0.s/lat0.l;
           28                 r0 = lat0.c/lat0.s + lat0.l;
           29         } else {
           30                 a = (lat1.c-lat0.c)/(lat0.l-lat1.l);
           31                 r0 = ((lat0.c+lat1.c)/a + lat1.l + lat0.l)/2;
           32         }
           33         return Xsimpleconic;
           34 }