3.1.4 World Coordinates in C

World Coordinates in C

We also support conversion between hh:mm:ss [+-]dd:mm:ss format and floating point degrees for plain, ANSI C based applications.

The following structs, defined in worldCoords.h , represent the world coordinate values:

 
typedef struct {  
    int hours;  
    int min; 
    double sec; 
    double val;		 
WC_HMS; 
typedef struct {  
    WC_HMS ra, dec; 
} WC;

A number of routines are defined to operate on the WC struct, so that you can specify the coordinates of an object as doubles in degrees or in hh:mm:ss [+-]dd:mm:ss format:

World Coordinate C Utility Routines
Routine	Description
`wcInitNull`	initialize null world coordinates
`wcIsNull`	return true if the given coords are null
`wcInitFromStrings`	initialize world coords from char strings containing RA and DEC
`wcInitFromHMS`	initialize from RA, DEC in H:M:S D:M:S format and equinox
`wcInitFromDeg`	initialize from RA, DEC in degrees and equinox
`wcPrint`	print RA and DEC to the given buffers in the given equinox

See worldCoords(3) for more details.