WCSLIB version 3.x (2003/04/01)
-------------------------------

* FORTRAN is now supported via a set of wrappers on the C library.
  Refer to the README file.


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

* Fixed CUBEFACE handling in WCSSET.

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.

* Changed the call sequence to PRJSET to return PHI0 along with THETA0.

* Fixed a problem in WCSMIX caused by numerical imprecision which 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 and TCEL, and
  replaced references to LONGPOLE with LONPOLE.

* Augmented the error reports in TWCS2.

* Modified PROJEX in TPROJ1 and PRJPLT in TPROJ2 to use the generic driver
  routines PRJSET, PRJFWD and PRJREV.  PRJPLT also now uses the projection
  type encoded in PRJ(11).

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

* Added generic driver routines PRJSET, PRJFWD and PRJREV.  These are keyed to
  specific projection routines via the value of PRJ(11) which now differs for
  each projection.

* 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.

* A bug in the translation from NCP to SIN in WCSFWD and WCSREV was fixed;
  they did not honour PRJ(11) set to -1 to disable strict bounds checking.

* A bug in WCSMIX was fixed - it was relying on the WCS array to have
  been initialized beforehand.

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

* Check for invalid (X,Y) in ZEAREV.

* Declare COSD and SIND in WCSFWD and WCSREV, reported by Clive Page
  (cgp@star.le.ac.uk).

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

* 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(11) 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.

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

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).

* (Internal change) Stopped PRJ(11) doing double service in any projection.
  It is now set and tested for a specific magic value rather than simply being
  non-zero.

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

* Implemented the CUBEFACE axis for quadcube projections.

* Added a new test program, TWCS1, to verify closure of WCSFWD and WCSREV.
  The old TWCS test program is now called TWCS2.

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.

* Increased the dimension of the WCS array from WCS(0:2) to WCS(0:3) to allow
  for future handling of the CUBEFACE keyword - WCS(3) will store an index to
  the CUBEFACE axis.  This affects the call sequences of WCSSET, WCSFWD,
  WCSREV, and WCSMIX.


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

The main change of interest to programmers is that of changed call sequences
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.f and test program tlin.f.

* 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 call sequences 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 call sequences
  have been extended to return native coordinates.  The related parameter
  array is now called CEL instead of WCS.

* 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) which 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 which have their
  reference point away from the native pole.  In investigating this a
  deficiency with the formalism was discovered which 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 CEL parameter array (formerly WCS) has been extended to
  accomodate LATPOLE as CEL(4), and the flag variable is now CEL(5) (formerly
  WCS(4)).

* 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 3.1 2003/04/28 04:31:08 mcalabre Exp $
