WCSLIB version 3.4 (2004/02/11)
-------------------------------

* In aitx2s(), apply the boundary condition 0.5 <= Z^2 <= 1 given after
  Eq. (109) in WCS Paper II to detect outlying pixels.

* Fixed several special-case bugs in celset():

  1) For theta_0 = 90, in substituting the default value for phi_p (LONPOLE),

     a) for the special case when delta_0 = 90, celset() provided the wrong
        value (180 instead of 0),

     b) celset() neglected to add phi_0 (normally 0).

  2) For theta_0 != 90,

     a) for the special case when delta_0 = -90, celset() incorrectly computed
        delta_p (as theta_0 instead of -theta_0),

     b) for the special case when delta_p = +90 (or -90), celset() neglected
        to subtract (or add) phi_0 (normally 0).

  3) For |delta_0| = 90, celset() incorrectly allowed the particular, invalid,
     value of phi_p (LONPOLE) that put the other pole at the fiducial point.

  4) For theta_0 = 0, delta_0 = 0 LATPOLE determines delta_p completely.  For
     LATPOLE > 90 celset() now sets delta_p to 90, and for LATPOLE < -90 it
     sets it to -90.

* Additional refinements in celset():

  1) cel->ref[2] is normalized in the range [-180,180].

  2) Account for rounding error in the computation of delta_p.

* sphx2s() and sphs2x() incorrectly handled the "change in the origin of
  longitude" special case that arises when delta_p = -90, in the even more
  restrictive case where |theta| = 90 also; it applied Eq. (3) instead of
  Eq. (4) of Paper II.

* Added a new test program, tcel2.c, to exercise celset() more thoroughly.
  Renamed the original tcel.c to tcel1.c and modified the Makefile to suit.

WCSLIB version 3.3 (2003/10/21)
-------------------------------

* In celset(), the default value for phi_p (LONPOLE) is

     phi_p = phi_0 + ((delta_0 < theta_0) ?  180.0 : 0.0)

  Previously phi_0 (which is normally zero) was not added.  Reported by
  David Berry (dsb@ast.man.ac.uk).

* wcsprt() and linprt() now check that the structs have been initialized.

* In wcsini(), when the wcsprm flag is -1 also set the linprm flag to -1 to
  force initialization of the memory managed by linset().

* wcsset() now explicitly initializes the celprm and spcprm structs via
  celini() and spcini().

* Fixed syntax errors in the macro definitions of linrev_errmsg and
  linfwd_errmsg.

* In Makefile, added the -ansi option to gcc to force it to behave like a
  strict ANSI C compiler, specifically in setting the __STDC__ preprocessor
  macro.

WCSLIB version 3.2 (2003/09/09)
-------------------------------

* Added the facility of setting the flag member of a wcsprm struct to -1
  before calling wcsini() for the first time in order to initialize memory
  management.  Likewise for linprm and linini().

* Renamed wcscpy() to wcscopy() to avoid a conflict with the Posix "wide
  character string" function of the same name (wchar.h).  In particular, this
  is used by the GNU C++ string class.

* The higher level functions (wcs, cel, spc) no longer return prematurely if
  some of the input coordinate values are invalid.

* All functions now test whether a null pointer for the particular struct
  (wcsprm, celprm, etc.) has been passed to them.

* Function return codes have been rationalized into a consistent set within
  each of the wcs, cel, lin, prj, spc, and spx suites of functions.  Error
  messages to match these error codes are now encoded in a single character
  array, e.g. wcs_errmsg and prj_errmsg, instead of a separate array for each
  function.  Macro definitions for the older character arrays (e.g.
  wcsini_errmsg) have been provided for backward compatibility.

* Declared prj_stat as extern in prj.h.

WCSLIB version 3.1 (2003/04/29)
-------------------------------

* Added "global" and "divergent" prjprm struct informational members to record
  whether the projection is capable of mapping the whole sphere, and whether
  it is divergent in latitude.

* Function cylfix() provided to fix WCS FITS header cards for malformed
  cylindrical projections (c.f. Paper II, Sect. 7.3.4).

* Added support for CUNITi cards to wcsprm (but not currently implemented).

* Added macro implementations of the trigd functions to wcstrig.h, enabled if
  WCSTRIG_MACRO is defined.

* Improved printing of the WCSLIB structs.

* Added macro definitions for the lengths of the WCSLIB structs measured in
  sizeof(int) units (mainly for the FORTRAN wrappers).

WCSLIB version 3.0 (2003/04/01)
-------------------------------
Beta release.

* Fully vectorized function interfaces (C preprocessor macros are available
  to implement the scalar interfaces of the proj.c, sph.c, and lin.c routines
  from WCSLIB 2.x).

* Implementation of Paper II, Sect. 2.5: User-specified (phi0, theta0).

* Implementation of Paper III (excluding "-TAB").

* Memory management is now implemented in the upper-level (wcs.c) routines.

* New extensible design should accomodate Paper IV (and any other) without
  further change to the function interfaces.

WCSLIB version 2.9 (2002/04/03)
-------------------------------

* Fixed a bug with alias translation in wcsset().

* Added a conditional compilation directive to lin.c for Apple's MacOS X.

WCSLIB version 2.8 (2001/11/16)
-------------------------------

* Added support for the SZP projection with szpset(), szpfwd() and szprev(),
  and generalized AZP with support for the tilt parameter, gamma.

* Added phi0 to the prjprm struct, this is set by the projection
  initialization routines along with theta0.

* Fixed a problem in wcsmix() caused by numerical imprecision that could
  cause it not to recognize when convergence was reached; break out of the
  loop early if a discontinuity is detected.

* Clarified the usage of vspan in the prologue to wcsmix().

* Fixed comments relating to LATPOLE in the prologue to cel.c and tcel.c, and
  replaced references to LONGPOLE with LONPOLE.

* Augmented the error reports in twcs2.

* Modified projex() in tproj1 and prjplt() in tproj2 to make use of the
  information stored in the prjprm struct.

WCSLIB version 2.7 (2001/02/19)
-------------------------------

* Added generic driver routines prjset(), prjfwd() and prjrev().  These invoke
  specific projection routines via the pointer-to-function elements, prjfwd
  and prjrev, transferred to the prjprm struct from celprm.

* Added code (3-letter projection code) and theta0 (reference latitude)
  elements to prjprm.

* The projection code for the Sanson-Flamsteed projection is now SFL.  The
  upper-level routines, wcsset(), wcsfwd(), and wcsrev(), recognize GLS as an
  alias for this.

* wcsset() now recognizes 'xyLN/xyLT' axis pairs.

* Two bugs in the translation from NCP to SIN in wcsfwd() and wcsrev() were
  fixed: (1) the projection parameter was computed incorrectly and (2) they
  did not honour prj->flag set to -1 to disable strict bounds checking.

* A bug in wcsmix() was fixed - it was relying on the wcsprm struct to have
  been initialized beforehand.

* The test programs now use the cpgplot interface to PGPLOT, the old tpgc.c
  and tpgf.f wrappers have been removed.

WCSLIB version 2.6 (2000/05/10)
-------------------------------

* Check for invalid (x,y) in zearev().

* In wcsmath.h, guard against prior definition of PI and other preprocessor
  variables.

WCSLIB version 2.5 (1999/12/14)
-------------------------------

* Added copyright notice to header files and prefixed include guard names with
  "WCSLIB_".

* Fixed cube face handling in wcsfwd() and wcsrev(), reported by Doug Mink
  (dmink@cfa.harvard.edu).  Allow more general face layout in the inverse
  quadcube projections.

* Fixed the problem in wcsmix() where it failed to find a valid solution when
  the solution point lay at a native pole of a projection in which the pole is
  represented as a finite interval.  However, wcsmix() will only ever return
  one solution even when two or more valid solutions may exist.

* wcsmix() now accepts viter in the range 5 - 10, the specified value will be
  pushed up or down into this range if necessary.

* The projection routines for AZP, TAN, SIN, ZPN, and COP now return error 2
  if (phi,theta) correspond to the overlapped (far) side of the projection.
  This strict bounds checking can be switched off by setting prj->flag to -1
  (rather than 0) when the projections are initialized.

* The upper level routines, wcsset(), wcsfwd(), wcsrev(), and wcsmix(), now
  recognize the NCP projection and convert it to the equivalent SIN
  projection.  The lower level routines do not recognize NCP.

* Extracted definitions of mathematical constants (PI etc.) from proj.h into
  wcsmath.h in order to avoid conflicts with their definition in math.h in
  some systems (such as Linux).

* Describe the two alternate representations of the quadcube projections
  (i.e. faces laid out or stacked) in the prologue of wcs.c.

WCSLIB version 2.4 (1996/09/23)
-------------------------------

* In sinrev(), cscrev(), qscrev(), and tscrev(), return error 2 if (x,y) do
  not lie within the perimeter of the projection.  In sinrev(), stop the
  computation of phi for the "synthesis" projection being applied to the pure
  "orthographic" case.  Reported by David Berry (dsb@ast.man.ac.uk).

* (Internal change) Renamed variables l <-> m in the quadcube projections to
  accord with standard usage (and revised WCS draft paper).

WCSLIB version 2.3 (1996/06/24)
-------------------------------

* Fixed two bugs in zpnset() reported by David Berry (dsb@ast.man.ac.uk).  The
  first led to an incorrect determination of the degree of the polynomial and
  would mainly have affected the efficiency of zpnrev().  The second affected
  the determination of the boundary of the projection but would only have been
  significant for projections with a point of inflection between 9 and 10
  degrees of the pole.

* Replaced usage of alloca() in lin.c with malloc() and free() for portability
  as suggested by Klaus Banse, ESO (kbanse@eso.org).

* Allow for C implementations that provide their own versions of cosd(),
  sind(), tand(), acosd(), asind(), atand(), and atan2d().  From Klaus Banse,
  ESO (kbanse@eso.org).

* Implemented the CUBEFACE axis for quadcube projections.

* Made all function prototypes const-correct.

* Adapted the header files to C++ usage.

* Added a new test program, twcs1, to verify closure of wcsfwd() and
  wcsrev().  The old twcs test program is now called twcs2.

* Added external arrays of error messages indexed by function return value.
  For example, extern const char *wcsmix_errmsg[] for wcsmix().  Messages for
  the many proj.c functions are in prjfwd_errmsg[], etc.


WCSLIB version 2.2 (1996/01/18)
-------------------------------

* Amended the projection equations for the conics (COP, COD, COE, COO) and
  Bonne's projection (BON) to correctly handle southern hemisphere projections
  with PROJP1 < 0 (reported by Lindsay Davis, NOAO).  Revised tproj1 and
  tproj2 to test such cases.


WCSLIB version 2.1 (1995/11/17)
-------------------------------

The main change of interest to programmers is that of changed argument lists
for wcsfwd() and wcsrev() as described below.

* The WCS linear transformations are now implemented in WCSLIB, complete with
  matrix inverter.  The new files are lin.c, lin.h, and test program tlin.c.

* Given either the celestial longitude or latitude plus an element of the
  pixel coordinate a new routine, wcsmix(), solves for the remaining elements
  by iterating on the unknown celestial coordinate element using wcsfwd().

* The high level driver routines wcsfwd(), wcsrev(), and wcsmix() now apply
  the full WCS algorithm chain (except for pixel regularization table),
  including parsing the CTYPEn header cards and computing non-celestial
  elements of the world coordinate.  This required a change to their argument
  lists which now more closely reflect the sequence of algorithms applied.  A
  new routine, wcsset(), parses the CTYPEn.

* The high level driver routines of WCSLIB 1.0 are available as intermediate
  level drivers celset(), celfwd(), and celrev(), but note that their argument
  lists have been extended to return native coordinates.  The related struct
  is now called celprm instead of wcsprm.

* The reference point for conic projections is now at the midpoint of the
  standard parallels.  The FITS header cards PROJP1 and PROJP2 now give the
  half-sum (midpoint) and half-difference of the latitudes of the standard
  parallels; previously they gave the latitudes of the standard parallels
  themselves.  The change is reflected in this release of WCSLIB.

* A bug in celset() (formerly wcsset()) that misapplied WCS draft equations
  7 has been fixed (thanks to Rick Ebert IPAC/JPL and Lindsey Davis, NOAO for
  reporting this).  This affected the computation of Euler angles for the
  celestial coordinate transformation for those projections that have their
  reference point away from the native pole.  In investigating this a
  deficiency with the formalism was discovered that led to the introduction
  of a LATPOLE FITS header card which may be used to disambiguate where
  CRVAL1, CRVAL2, and LONGPOLE do not uniquely determine the latitude of the
  native pole.  The celprm struct (formerly wcsprm) has been extended to
  accomodate LATPOLE.

* Default values of LONGPOLE and LATPOLE are now supported and their use is
  recommended where appropriate.

* Numerical precision was being lost near the native poles in the SIN, AIR,
  and QSC projections and this has been recovered (reported by Lindsey Davis,
  NOAO).  Floating underflows in CSC are now avoided.

* Numerical precision was also lost in certain circumstances in the spherical
  coordinate transformation routines and this has been fixed.

* The test programs have been enhanced in various ways and the library has
  been validated on an SGI machine using both 32-bit and 64-bit compilers.

WCSLIB version 1.0 (1995/01/31)
-------------------------------

Initial release.

------------------------------------------------------------------------------
$Id: CHANGES,v 3.4 2004/02/11 00:11:52 mcalabre Exp $
