simpleconic.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 }