NASA Ocean Color

ocssw V2022

 #ifndef ISIN_H
 #define ISIN_H
  
 /******************************************************************************
 NAME                                ISIN.H
  
 PURPOSE:    Integerized Sinusoidal Library Header - constants, data 
             structures and prototypes for integerized sinusoidal library 
             functions.
  
 ******************************************************************************/
  
 /* Status returned */
 #define ISIN_SUCCESS 0          /* Successful return */
 #define ISIN_ERROR -1           /* Error return */
 #define ISIN_ERANGE -2          /* Input variable out of range */
  
 /* ISIN related defines */
 #define TWOPI_INV  (1.0 / (2.0 * PI))
 #define NROW_MAX  (360 * 3600)  /* Maximum number of rows (zones) */
 #define NZONE_MAX (360 * 3600)  /* Maximum number of longitudinal zones */
 #define EPS_SPHERE (1.0e-10)    /* Minimum sphere radius */
 #define EPS_CNVT 0.01           /* Doubles must be within this of an integer 
                                    to be valid */
 #define ISIN_KEY 212589603      /* Key to verify correct data structure */
  
 /* 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 */
     const char *str;                  /* Error message */
 }
 error_t;
  
 /* Initialize integerized sinusoidal forward transformations */
 long isinusforinit
 ( 
     double sphere, 
     double lon_cen_mer, 
     double false_east,
     double false_north, 
     double dzone, 
     double djustify 
 );
  
 Isin_t *Isin_for_init
 (
     double sphere,
     double lon_cen_mer,
     double false_east, 
     double false_north,
     long nrow, 
     int ijustify 
 );
  
 /* Initialize integerized sinusoidal inverse transformations */
 long isinusinvinit
 ( 
     double sphere, 
     double lon_cen_mer, 
     double false_east,
     double false_north, 
     double dzone, 
     double djustify 
 );
  
 Isin_t *Isin_inv_init
 ( 
     double sphere,
     double lon_cen_mer,
     double false_east, 
     double false_north,
     long nrow, 
     int ijustify 
 );
  
 /* Forward mapping; converts geographic coordinates ('lon', 'lat')
  * to map projection coordinates ('x', 'y') */
 long isinusfor
 (
     double lon, 
     double lat, 
     double *x, 
     double *y 
 );
  
 int Isin_fwd
 (
     const Isin_t * this, 
     double lon, 
     double lat, 
     double *x, 
     double *y 
 );
  
 /* Inverse mapping; converts map projection coordinates ('x', 'y') to
  * geographic coordinates ('lon', 'lat') */
 long 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 * this 
 );
  
 int Isin_inv_free
 ( 
     Isin_t * this 
 );
  
 #endif