1 #include <u.h> 2 #include <libc.h> 3 #include "map.h" 4 5 static struct coord stdp0, stdp1; 6 static double k; 7 8 static int Xlambert(struct place * place,double * x,double * y)9Xlambert(struct place *place, double *x, double *y) 10 { 11 double r; 12 if(place->nlat.l < -80.*RAD) 13 return(-1); 14 if(place->nlat.l > 89.*RAD) 15 r = 0; /* slovenly */ 16 else 17 r = stdp0.c*exp(0.5*k*log( 18 (1+stdp0.s)*(1-place->nlat.s)/((1-stdp0.s)*(1+place->nlat.s)))); 19 if(stdp1.l<0.) 20 r = -r; 21 *x = - r*sin(k * place->wlon.l); 22 *y = - r*cos(k * place->wlon.l); 23 return(1); 24 } 25 26 proj lambert(double par0,double par1)27lambert(double par0, double par1) 28 { 29 double temp; 30 if(fabs(par0)>fabs(par1)){ 31 temp = par0; 32 par0 = par1; 33 par1 = temp; 34 } 35 deg2rad(par0, &stdp0); 36 deg2rad(par1, &stdp1); 37 if(fabs(par1+par0)<.1) 38 return(mercator()); 39 if(fabs(par1-par0)<.1) 40 return(perspective(-1.)); 41 if(fabs(par0)>89.5||fabs(par1)>89.5) 42 return(0); 43 k = 2*log(stdp1.c/stdp0.c)/log( 44 (1+stdp0.s)*(1-stdp1.s)/((1-stdp0.s)*(1+stdp1.s))); 45 return(Xlambert); 46 } 47