    typedef struct {
      int   month;            /* (1-12). */
      int   day;              /* (1-31).   */
      int   year;             /* (eg. 1993). */
      int   hour;             /* (0-23). */
      int   minute;           /* (0-59).*/
      float sec;              /* second + fraction of second. */
      float dx, dy;           /* Size of cell in km. */
      int   nx, ny;           /* Number of cells. */
      int   radar_x, radar_y; /* Location of center of radar. */
      float height;           /* Height of this Carpi. */
      float lat, lon;         /* Lat/lon of lower left corner of Carpi. */
      char  radar_type[50];   /* Radar types. */
      int   field_type;       /* Same as for Radar. */
      int   interp_method;    /* ??? string describing interpolation method. */
      float (*f)(Carpi_value x);    /* Data conversion function. f(x). */
      Carpi_value (*invf)(float x); /* Data conversion function. invf(x). */
      Carpi_value **data;     /* data[ny][nx] */
    } Carpi;