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#include <u.h>
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#include <libc.h>
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#include "map.h"
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static struct coord stdp0, stdp1;
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static double k;
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static int
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Xlambert(struct place *place, double *x, double *y)
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{
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	double r;
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	if(place->nlat.l < -80.*RAD)
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		return(-1);
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	if(place->nlat.l > 89.*RAD)
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		r = 0;	/* slovenly */
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	else
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		r = stdp0.c*exp(0.5*k*log(
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		   (1+stdp0.s)*(1-place->nlat.s)/((1-stdp0.s)*(1+place->nlat.s))));
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	if(stdp1.l<0.)
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		r = -r;
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	*x = - r*sin(k * place->wlon.l);
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	*y = - r*cos(k * place->wlon.l);
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	return(1);
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}
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proj
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lambert(double par0, double par1)
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{
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	double temp;
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	if(fabs(par0)>fabs(par1)){
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		temp = par0;
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		par0 = par1;
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		par1 = temp;
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	}
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	deg2rad(par0, &stdp0);
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	deg2rad(par1, &stdp1);
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	if(fabs(par1+par0)<.1)
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		return(mercator());
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	if(fabs(par1-par0)<.1)
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		return(perspective(-1.));
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	if(fabs(par0)>89.5||fabs(par1)>89.5)
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		return(0);
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	k = 2*log(stdp1.c/stdp0.c)/log(
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		(1+stdp0.s)*(1-stdp1.s)/((1-stdp0.s)*(1+stdp1.s)));
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	return(Xlambert);
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}