typedef struct {
int sweep_num; /* Integer sweep number. */
float elev; /* Elevation angle (mean) for the sweep. */
float beam_width; /* This is in the ray header too. */
float vert_half_bw; /* Vertical beam width divided by 2 */
float horz_half_bw; /* Horizontal beam width divided by 2 */
int nrays;
float (*f)(Range x); /* Data conversion function. f(x). */
Range (*invf)(float x); /* Data conversion function. invf(x). */
} Sweep_header;