26 lines
431 B
C
26 lines
431 B
C
#include <u.h>
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#include <libc.h>
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#include "map.h"
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static int
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Xmollweide(struct place *place, double *x, double *y)
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{
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double z;
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double w;
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z = place->nlat.l;
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if(fabs(z)<89.9*RAD)
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do { /*newton for 2z+sin2z=pi*sin(lat)*/
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w = (2*z+sin(2*z)-PI*place->nlat.s)/(2+2*cos(2*z));
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z -= w;
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} while(fabs(w)>=.00001);
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*y = sin(z);
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*x = - (2/PI)*cos(z)*place->wlon.l;
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return(1);
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}
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proj
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mollweide(void)
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{
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return(Xmollweide);
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}
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