34 lines
644 B
C
34 lines
644 B
C
#include <u.h>
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#include <libc.h>
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#include "map.h"
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static double r0, a;
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static int
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Xsimpleconic(struct place *place, double *x, double *y)
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{
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double r = r0 - place->nlat.l;
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double t = a*place->wlon.l;
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*x = -r*sin(t);
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*y = -r*cos(t);
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return 1;
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}
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proj
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simpleconic(double par0, double par1)
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{
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struct coord lat0;
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struct coord lat1;
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deg2rad(par0,&lat0);
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deg2rad(par1,&lat1);
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if(fabs(lat0.l+lat1.l)<.01)
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return rectangular(par0);
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if(fabs(lat0.l-lat1.l)<.01) {
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a = lat0.s/lat0.l;
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r0 = lat0.c/lat0.s + lat0.l;
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} else {
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a = (lat1.c-lat0.c)/(lat0.l-lat1.l);
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r0 = ((lat0.c+lat1.c)/a + lat1.l + lat0.l)/2;
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}
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return Xsimpleconic;
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}
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