short_way.c

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00001 #include "gis.h"
00002 /* For lat-lon,
00003  *   this routine adjusts the values of the longitudes so that
00004  *   the difference between them is less than 180.
00005  *   It does NOT change their true position.
00006  * For other databases
00007  *   this routine does nothing
00008  */
00009 
00023 int G_shortest_way (double *east1,double *east2)
00024 {
00025     if (G_projection() == PROJECTION_LL)
00026     {
00027         if (*east1 > *east2)
00028             while ((*east1-*east2) > 180)
00029                 *east2 += 360;
00030         else if (*east2 > *east1)
00031             while ((*east2-*east1) > 180)
00032                 *east1 += 360;
00033     }
00034 
00035     return 0;
00036 }

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