WCSLIB  5.16
Overview of WCSLIB

WCSLIB is documented in the prologues of its header files which provide a detailed description of the purpose of each function and its interface (this material is, of course, used to generate the doxygen manual). Here we explain how the library as a whole is structured. We will normally refer to WCSLIB 'routines', meaning C functions or Fortran 'subroutines', though the latter are actually wrappers implemented in C.

WCSLIB is layered software, each layer depends only on those beneath; understanding WCSLIB first means understanding its stratigraphy. There are essentially three levels, though some intermediate levels exist within these:

Complementary to the C library, a set of wrappers are provided that allow all WCSLIB C functions to be called by Fortran programs, see below.

Plotting of coordinate graticules is one of the more important requirements of a world coordinate system. WCSLIB provides a PGPLOT-based subroutine, PGSBOX (Fortran), which handles general curvilinear coordinates via a user-supplied function - PGWCSL provides the interface to WCSLIB. A C wrapper, cpgsbox(), is also provided, see below.

Several utility programs are distributed with WCSLIB: