Subject: WCS code from the IDL Astronomy Library

From: dwells at nrao.edu (Don Wells)
Date: Thu, 13 Oct 1994 22:06:18 GMT

I am pleased to announce the availability of URL

    ftp://fits.cv.nrao.edu/fits/src/wcs/idl_wcs_code.tar.gz

                 29445 Oct  4 16:36 idl_wcs_code.tar.gz

The tar file contains:

gunzip -c idl_wcs_code.tar.gz | tar tvf - 
rw-r--r--106/16   4993 Oct  4 16:35 1994 README
rw-r--r--106/16  51361 Oct  4 16:31 1994 wcs_demo.pro
rw-r--r--106/16  34591 Oct  4 16:31 1994 wcssph2xy.pro
rw-r--r--106/16  35629 Oct  4 16:31 1994 wcsxy2sph.pro

The three *.pro files in this tar file have been extracted from the
GSFC IDL Astronomy Library (see ftp://idlastro.gsfc.nasa.gov/README)
with permission from Wayne Landsman <landsman at uit.gsfc.nasa.gov>.  The
algorithms implemented in this package are believed to be in
substantial conformance with the Greisen & Calabretta draft WCS
proposal which is available at

        ftp://fits.cv.nrao.edu/fits/documents/wcs/wcs.all.ps.Z

The three IDL files are quite readable, and can probably be
transliterated into other languages without too much difficulty. They
are the first implementation of the Greisen & Calabretta paper. The
projections implemented by this package are:

;  FITS  Number  Name                       Comments
;  code   code
;  ----  ------  -----------------------    -----------------------------------
;   DEF     0    Default = Cartesian
;   AZP     1    Zenithal perspective       projp1 required
;   TAN     2    Gnomic                     AZP w/ projp1 = 0
;   SIN     3    Orthographic               AZP w/ projp1 = Infinity (>10^14)
;   STG     4    Stereographic              AZP w/ projp1 = 1
;   ARC     5    Zenithal Equidistant
;   ZPN     6    Zenithal polynomial        prop1-projp9 required, useless
;   ZEA     7    Zenithal equal area
;   AIR     8    Airy                       projp1 required
;   CYP     9    Cylindrical perspective    projp1 and projp2 required
;   CAR    10    Cartesian
;   MER    11    Mercator
;   CEA    12    Cylindrical equal area     projp1 required
;   COP    13    Conical perspective        projp1 and projp2 required
;   COD    14    Conical equidistant        projp1 and projp2 required
;   COE    15    Conical equal area         projp1 and projp2 required
;   COO    16    Conical orthomorphic       projp1 and projp2 required
;   BON    17    Bonne's equal area         projp1 required
;   PCO    18    Polyconic
;   GLS    19    Sinusoidal
;   PAR    20    Parabolic
;   AIT    21    Hammer-Aitoff
;   MOL    22    Mollweide
;   CSC    23    Cobe Quadrilateralized     convergence of inverse is poor
;                Spherical Cube
;   QSC    24    Quadrilateralized 
;                Spherical Cube
;   TSC    25    Tangential Spherical Cube

Test program wcs_demo says:

; COPYRIGHT NOTICE:

;       Copyright 1991, The Regents of the University of California. This
;       software was produced under U.S. Government contract (W-7405-ENG-36)
;       by Los Alamos National Laboratory, which is operated by the
;       University of California for the U.S. Department of Energy.
;       The U.S. Government is licensed to use, reproduce, and distribute
;       this software. Neither the Government nor the University makes
;       any warranty, express or implied, or assumes any liability or
;       responsibility for the use of this software.
;
; AUTHOR:
;
;       Rick Balsano
        ^^^^^^^^^^^^
        work done while he was at Los Alamos National Laboratory,
	circa 1991-1993.

The calling sequences are:

; NAME:
;       WCSSPH2XY 
;
; PURPOSE:
;       To convert spherical (longitude and latitude -- sky) coordinates to x 
;       and y (map) angular coordinates.  This procedure is the inverse of 
;       WCSXY2SPH.    See WCS_DEMO for example of use.
;
; CALLING SEQUENCE:
;       wcssph2xy, longitude, latitude, x, y, [ map_type , CTYPE = ,
;               FACE =,PROJP1 = , PROJP2= , CRVAL = , CRXY = , LONGPOLE = ,
;               NORTH_OFFSET =, SOUTH_OFFSET =, BADINDEX =]
;

    -=-=-=-=-=-

; NAME:
;       WCSXY2SPH  
;
; PURPOSE:
;       To convert x and y (map) coordinates to spherical (longitude and 
;       latitude or sky) coordinates.    This procedure is the inverse of
;       WCSSPH2XY.
;
; CALLING SEQUENCE:
;
;   wcsxy2sph, x, y, longitude, latitude, [map_type], [ CTYPE = ,$
;             FACE = ,PROJP1 = , PROJP2 = ,CRVAL =, CRXY =, LONGPOLE= ]

--
  Donald C. Wells         Associate Scientist         dwells at nrao.edu
                    http://fits.cv.nrao.edu/~dwells
  National Radio Astronomy Observatory                +1-804-296-0277
  520 Edgemont Road,   Charlottesville, Virginia       22903-2475 USA