convert_coord.h

用于2维的射线追踪

#ifndef _CONVERT_COORD_H_
#define _CONVERT_COORD_H_

#ifndef _COORD_3D_H_
#define _COORD_3D_H_
struct point3d_t {
     float lat;          /**< latitude */
     float lon;          /**< longitude */
     float prf;          /**< depth */
};
#endif

#ifndef _COORD_GEO_H_
#define _COORD_GEO_H_
struct coord_geo_t {
       double lat; /**< latitude   */
       double lon; /**< longitude (in rad or degree ?) */
       double prof;/**< depth (in km)*/
};
#endif                                                                                                        
#ifndef _COORD_CART_H_
#define _COORD_CART_H_
struct coord_cart_t {
       double x;   /**< plan xy axe equateur */
       double y;   /**< plan xz axe meridien origine */
       double z;         /**< depth (in kms) */
};
#endif

#if defined _COORD_GEO_H_ && defined _COORD_3D_H_
struct coord_geo_t * point3d2geo( struct point3d_t *p) {
	  struct coord_geo_t *g=malloc(sizeof(struct coord_geo_t));
	  g->lat = p->lat * TO_RAD;
	  g->lon = p->lon * TO_RAD;
	  g->prof = p->prf;
	  return(g);
}
#endif
#if defined _COORD_CART_H_ && defined _COORD_3D_H_
/**
 * coordinates transformation : point3d (georaphic) (angles are in radians)
 * coordinates to cartesian coordinates                           
 */ 
struct coord_cart_t * point3d2cart ( const struct point3d_t *point3d) {
	struct coord_cart_t *coord_cart;
	double r, cos_lat, sin_lat, cos_lon, sin_lon;

	coord_cart =  (struct coord_cart_t *) malloc (sizeof (struct coord_cart_t));
	assert (coord_cart);

	r = RE - point3d->prf;
	cos_lat = cos (point3d->lat * TO_RAD);
	sin_lat = sin (point3d->lat * TO_RAD);
	cos_lon = cos (point3d->lon * TO_RAD);
	sin_lon = sin (point3d->lon * TO_RAD);
	
	coord_cart->x = r * cos_lat * cos_lon;
	coord_cart->y = r * cos_lat * sin_lon;
	coord_cart->z = r * sin_lat;
	
	return (coord_cart);
}
#endif
#endif