isin.h

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/******************************************************************************
NAME                                ISIN.H

PURPOSE:    Integerized Sinusoidal Library Header - constants, data 
            structures and prototypes for integerized sinusoidal library 
            functions.

PROGRAMMER                DATE          REASON
----------                ----          ------
Robert Wolfe (STX)        1-2-97        Initial version.
Raj Gejjagaraguppe (ARC)  1-15-97       Modified the code to work with
                                        GCTP software.
 
D*****************************************************************************/


#ifdef __cplusplus
extern "C" {
#endif

/* Status returned */

#define ISIN_SUCCESS 0    /* Successful return */
#define ISIN_ERROR -1     /* Error return */
#define ISIN_ERANGE -2    /* Input variable out of range */

/* Data Structures */

/* Row Type; Information for Eash Row (longitudinal band) in Projection */

typedef struct {
  long ncol;              /* Number of columns */
  long icol_cen;          /* Column number to left of center of grid */
  double ncol_inv;        /* Number of columns inverse */
} Isin_row_t;

/* Handle Type; Values assigned in 'Isin_init' */

typedef struct {
  double false_east;      /* Northing at projection origin */
  double false_north;     /* Easting at projection origin */
  double sphere;      /* Sphere radius (user's units) */
  double sphere_inv;      /* Sphere radius inverse (user's units) */
  double ang_size_inv;    /* Grid angular resolution inverse (1/rad)*/
  long nrow;          /* Number of rows (longitudinal zones) */
  long nrow_half;     /* Half of number of rows (longitudinal zones)*/
  double ref_lon;     /* Zero reference longitude (rad) */
  double lon_cen_mer;     /* Longitude of central meridian (rad) */
  int ijustify;       /* Justify flag (see Isin_init) */
  double col_dist;    /* Distance for one column in projection 
               * (user's units) */
  double col_dist_inv;    /* Distance for one column in projection inverse
               * (user's units) */
  Isin_row_t *row;    /* Row data structure */
  long key;       /* Data structure key */
} Isin_t;


/* Error Structure */
 
typedef struct {
  int num;             /* Error number */
  char *str;           /* Error message */
} error_t;
 

/* Prototypes */
 
/* Initialize integerized sinusoidal forward transformations */
 
int isinusforinit(double , double, double, double, double, double); 
 
Isin_t *Isin_for_init(double , double, double, double, long, int); 

/* Initialize integerized sinusoidal inverse transformations */

int isinusinvinit(double , double, double, double, double, double);

Isin_t *Isin_inv_init(double , double, double, double, long, int);

/* Forward mapping; converts geographic coordinates ('lon', 'lat')
 * to map projection coordinates ('x', 'y') */

int isinusfor(double, double, double *, double *);
 
int Isin_fwd(const Isin_t *, double, double, double *, double *); 

/* Inverse mapping; converts map projection coordinates ('x', 'y') to
 * geographic coordinates ('lon', 'lat') */

int isinusinv(double, double, double *, double *);
 
int Isin_inv(const Isin_t *, double, double, double *, double *); 

/* Deallocate the 'isin' data structure and array memory */

int Isin_for_free(Isin_t *);

int Isin_inv_free(Isin_t *);

/* Private function to handle errors */

static int Isin_error(const error_t *, const char *);


#ifdef __cplusplus
}
#endif