WCSLIB 8.0
wcs.h
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1/*============================================================================
2 WCSLIB 8.0 - an implementation of the FITS WCS standard.
3 Copyright (C) 1995-2023, Mark Calabretta
4
5 This file is part of WCSLIB.
6
7 WCSLIB is free software: you can redistribute it and/or modify it under the
8 terms of the GNU Lesser General Public License as published by the Free
9 Software Foundation, either version 3 of the License, or (at your option)
10 any later version.
11
12 WCSLIB is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
15 more details.
16
17 You should have received a copy of the GNU Lesser General Public License
18 along with WCSLIB. If not, see http://www.gnu.org/licenses.
19
20 Author: Mark Calabretta, Australia Telescope National Facility, CSIRO.
21 http://www.atnf.csiro.au/people/Mark.Calabretta
22 $Id: wcs.h,v 8.0 2023/06/15 04:18:49 mcalabre Exp $
23*=============================================================================
24*
25* WCSLIB 8.0 - C routines that implement the FITS World Coordinate System
26* (WCS) standard. Refer to the README file provided with WCSLIB for an
27* overview of the library.
28*
29*
30* Summary of the wcs routines
31* ---------------------------
32* Routines in this suite implement the FITS World Coordinate System (WCS)
33* standard which defines methods to be used for computing world coordinates
34* from image pixel coordinates, and vice versa. The standard, and proposed
35* extensions for handling distortions, are described in
36*
37= "Representations of world coordinates in FITS",
38= Greisen, E.W., & Calabretta, M.R. 2002, A&A, 395, 1061 (WCS Paper I)
39=
40= "Representations of celestial coordinates in FITS",
41= Calabretta, M.R., & Greisen, E.W. 2002, A&A, 395, 1077 (WCS Paper II)
42=
43= "Representations of spectral coordinates in FITS",
44= Greisen, E.W., Calabretta, M.R., Valdes, F.G., & Allen, S.L.
45= 2006, A&A, 446, 747 (WCS Paper III)
46=
47= "Representations of distortions in FITS world coordinate systems",
48= Calabretta, M.R. et al. (WCS Paper IV, draft dated 2004/04/22),
49= available from http://www.atnf.csiro.au/people/Mark.Calabretta
50=
51= "Mapping on the HEALPix grid",
52= Calabretta, M.R., & Roukema, B.F. 2007, MNRAS, 381, 865 (WCS Paper V)
53=
54= "Representing the 'Butterfly' Projection in FITS -- Projection Code XPH",
55= Calabretta, M.R., & Lowe, S.R. 2013, PASA, 30, e050 (WCS Paper VI)
56=
57= "Representations of time coordinates in FITS -
58= Time and relative dimension in space",
59= Rots, A.H., Bunclark, P.S., Calabretta, M.R., Allen, S.L.,
60= Manchester, R.N., & Thompson, W.T. 2015, A&A, 574, A36 (WCS Paper VII)
61*
62* These routines are based on the wcsprm struct which contains all information
63* needed for the computations. The struct contains some members that must be
64* set by the user, and others that are maintained by these routines, somewhat
65* like a C++ class but with no encapsulation.
66*
67* wcsnpv(), wcsnps(), wcsini(), wcsinit(), wcssub(), wcsfree(), and wcstrim(),
68* are provided to manage the wcsprm struct, wcssize() computes its total size
69* including allocated memory, and wcsprt() prints its contents. Refer to the
70* description of the wcsprm struct for an explanation of the anticipated usage
71* of these routines. wcscopy(), which does a deep copy of one wcsprm struct
72* to another, is defined as a preprocessor macro function that invokes
73* wcssub().
74*
75* wcsperr() prints the error message(s) (if any) stored in a wcsprm struct,
76* and the linprm, celprm, prjprm, spcprm, and tabprm structs that it contains.
77*
78* A setup routine, wcsset(), computes intermediate values in the wcsprm struct
79* from parameters in it that were supplied by the user. The struct always
80* needs to be set up by wcsset() but this need not be called explicitly -
81* refer to the explanation of wcsprm::flag.
82*
83* wcsp2s() and wcss2p() implement the WCS world coordinate transformations.
84* In fact, they are high level driver routines for the WCS linear,
85* logarithmic, celestial, spectral and tabular transformation routines
86* described in lin.h, log.h, cel.h, spc.h and tab.h.
87*
88* Given either the celestial longitude or latitude plus an element of the
89* pixel coordinate a hybrid routine, wcsmix(), iteratively solves for the
90* unknown elements.
91*
92* wcsccs() changes the celestial coordinate system of a wcsprm struct, for
93* example, from equatorial to galactic, and wcssptr() translates the spectral
94* axis. For example, a 'FREQ' axis may be translated into 'ZOPT-F2W' and vice
95* versa.
96*
97* wcslib_version() returns the WCSLIB version number.
98*
99* Quadcube projections:
100* ---------------------
101* The quadcube projections (TSC, CSC, QSC) may be represented in FITS in
102* either of two ways:
103*
104* a: The six faces may be laid out in one plane and numbered as follows:
105*
106= 0
107=
108= 4 3 2 1 4 3 2
109=
110= 5
111*
112* Faces 2, 3 and 4 may appear on one side or the other (or both). The
113* world-to-pixel routines map faces 2, 3 and 4 to the left but the
114* pixel-to-world routines accept them on either side.
115*
116* b: The "COBE" convention in which the six faces are stored in a
117* three-dimensional structure using a CUBEFACE axis indexed from
118* 0 to 5 as above.
119*
120* These routines support both methods; wcsset() determines which is being
121* used by the presence or absence of a CUBEFACE axis in ctype[]. wcsp2s()
122* and wcss2p() translate the CUBEFACE axis representation to the single
123* plane representation understood by the lower-level WCSLIB projection
124* routines.
125*
126*
127* wcsnpv() - Memory allocation for PVi_ma
128* ---------------------------------------
129* wcsnpv() sets or gets the value of NPVMAX (default 64). This global
130* variable controls the number of pvcard structs, for holding PVi_ma
131* keyvalues, that wcsini() should allocate space for. It is also used by
132* wcsinit() as the default value of npvmax.
133*
134* PLEASE NOTE: This function is not thread-safe.
135*
136* Given:
137* n int Value of NPVMAX; ignored if < 0. Use a value less
138* than zero to get the current value.
139*
140* Function return value:
141* int Current value of NPVMAX.
142*
143*
144* wcsnps() - Memory allocation for PSi_ma
145* ---------------------------------------
146* wcsnps() sets or gets the value of NPSMAX (default 8). This global variable
147* controls the number of pscard structs, for holding PSi_ma keyvalues, that
148* wcsini() should allocate space for. It is also used by wcsinit() as the
149* default value of npsmax.
150*
151* PLEASE NOTE: This function is not thread-safe.
152*
153* Given:
154* n int Value of NPSMAX; ignored if < 0. Use a value less
155* than zero to get the current value.
156*
157* Function return value:
158* int Current value of NPSMAX.
159*
160*
161* wcsini() - Default constructor for the wcsprm struct
162* ----------------------------------------------------
163* wcsini() is a thin wrapper on wcsinit(). It invokes it with npvmax,
164* npsmax, and ndpmax set to -1 which causes it to use the values of the
165* global variables NDPMAX, NPSMAX, and NDPMAX. It is thereby potentially
166* thread-unsafe if these variables are altered dynamically via wcsnpv(),
167* wcsnps(), and disndp(). Use wcsinit() for a thread-safe alternative in
168* this case.
169*
170*
171* wcsinit() - Default constructor for the wcsprm struct
172* -----------------------------------------------------
173* wcsinit() optionally allocates memory for arrays in a wcsprm struct and sets
174* all members of the struct to default values.
175*
176* PLEASE NOTE: every wcsprm struct should be initialized by wcsinit(),
177* possibly repeatedly. On the first invokation, and only the first
178* invokation, wcsprm::flag must be set to -1 to initialize memory management,
179* regardless of whether wcsinit() will actually be used to allocate memory.
180*
181* Given:
182* alloc int If true, allocate memory unconditionally for the
183* crpix, etc. arrays. Please note that memory is never
184* allocated by wcsinit() for the auxprm, tabprm, nor
185* wtbarr structs.
186*
187* If false, it is assumed that pointers to these arrays
188* have been set by the user except if they are null
189* pointers in which case memory will be allocated for
190* them regardless. (In other words, setting alloc true
191* saves having to initalize these pointers to zero.)
192*
193* naxis int The number of world coordinate axes. This is used to
194* determine the length of the various wcsprm vectors and
195* matrices and therefore the amount of memory to
196* allocate for them.
197*
198* Given and returned:
199* wcs struct wcsprm*
200* Coordinate transformation parameters.
201*
202* Note that, in order to initialize memory management,
203* wcsprm::flag should be set to -1 when wcs is
204* initialized for the first time (memory leaks may
205* result if it had already been initialized).
206*
207* Given:
208* npvmax int The number of PVi_ma keywords to allocate space for.
209* If set to -1, the value of the global variable NPVMAX
210* will be used. This is potentially thread-unsafe if
211* wcsnpv() is being used dynamically to alter its value.
212*
213* npsmax int The number of PSi_ma keywords to allocate space for.
214* If set to -1, the value of the global variable NPSMAX
215* will be used. This is potentially thread-unsafe if
216* wcsnps() is being used dynamically to alter its value.
217*
218* ndpmax int The number of DPja or DQia keywords to allocate space
219* for. If set to -1, the value of the global variable
220* NDPMAX will be used. This is potentially
221* thread-unsafe if disndp() is being used dynamically to
222* alter its value.
223*
224* Function return value:
225* int Status return value:
226* 0: Success.
227* 1: Null wcsprm pointer passed.
228* 2: Memory allocation failed.
229*
230* For returns > 1, a detailed error message is set in
231* wcsprm::err if enabled, see wcserr_enable().
232*
233*
234* wcsauxi() - Default constructor for the auxprm struct
235* -----------------------------------------------------
236* wcsauxi() optionally allocates memory for an auxprm struct, attaches it to
237* wcsprm, and sets all members of the struct to default values.
238*
239* Given:
240* alloc int If true, allocate memory unconditionally for the
241* auxprm struct.
242*
243* If false, it is assumed that wcsprm::aux has already
244* been set to point to an auxprm struct, in which case
245* the user is responsible for managing that memory.
246* However, if wcsprm::aux is a null pointer, memory will
247* be allocated regardless. (In other words, setting
248* alloc true saves having to initalize the pointer to
249* zero.)
250*
251* Given and returned:
252* wcs struct wcsprm*
253* Coordinate transformation parameters.
254*
255* Function return value:
256* int Status return value:
257* 0: Success.
258* 1: Null wcsprm pointer passed.
259* 2: Memory allocation failed.
260*
261*
262* wcssub() - Subimage extraction routine for the wcsprm struct
263* ------------------------------------------------------------
264* wcssub() extracts the coordinate description for a subimage from a wcsprm
265* struct. It does a deep copy, using wcsinit() to allocate memory for its
266* arrays if required. Only the "information to be provided" part of the
267* struct is extracted. Consequently, wcsset() need not have been, and won't
268* be invoked on the struct from which the subimage is extracted. A call to
269* wcsset() is required to set up the subimage struct.
270*
271* The world coordinate system of the subimage must be separable in the sense
272* that the world coordinates at any point in the subimage must depend only on
273* the pixel coordinates of the axes extracted. In practice, this means that
274* the linear transformation matrix of the original image must not contain
275* non-zero off-diagonal terms that associate any of the subimage axes with any
276* of the non-subimage axes. Likewise, if any distortions are associated with
277* the subimage axes, they must not depend on any of the axes that are not
278* being extracted.
279*
280* Note that while the required elements of the tabprm array are extracted, the
281* wtbarr array is not. (Thus it is not appropriate to call wcssub() after
282* wcstab() but before filling the tabprm structs - refer to wcshdr.h.)
283*
284* wcssub() can also add axes to a wcsprm struct. The new axes will be created
285* using the defaults set by wcsinit() which produce a simple, unnamed, linear
286* axis with world coordinate equal to the pixel coordinate. These default
287* values can be changed afterwards, before invoking wcsset().
288*
289* Given:
290* alloc int If true, allocate memory for the crpix, etc. arrays in
291* the destination. Otherwise, it is assumed that
292* pointers to these arrays have been set by the user
293* except if they are null pointers in which case memory
294* will be allocated for them regardless.
295*
296* wcssrc const struct wcsprm*
297* Struct to extract from.
298*
299* Given and returned:
300* nsub int*
301* axes int[] Vector of length *nsub containing the image axis
302* numbers (1-relative) to extract. Order is
303* significant; axes[0] is the axis number of the input
304* image that corresponds to the first axis in the
305* subimage, etc.
306*
307* Use an axis number of 0 to create a new axis using
308* the defaults set by wcsinit(). They can be changed
309* later.
310*
311* nsub (the pointer) may be set to zero, and so also may
312* *nsub, which is interpreted to mean all axes in the
313* input image; the number of axes will be returned if
314* nsub != 0x0. axes itself (the pointer) may be set to
315* zero to indicate the first *nsub axes in their
316* original order.
317*
318* Set both nsub (or *nsub) and axes to zero to do a deep
319* copy of one wcsprm struct to another.
320*
321* Subimage extraction by coordinate axis type may be
322* done by setting the elements of axes[] to the
323* following special preprocessor macro values:
324*
325* WCSSUB_LONGITUDE: Celestial longitude.
326* WCSSUB_LATITUDE: Celestial latitude.
327* WCSSUB_CUBEFACE: Quadcube CUBEFACE axis.
328* WCSSUB_SPECTRAL: Spectral axis.
329* WCSSUB_STOKES: Stokes axis.
330* WCSSUB_TIME: Time axis.
331*
332* Refer to the notes (below) for further usage examples.
333*
334* On return, *nsub will be set to the number of axes in
335* the subimage; this may be zero if there were no axes
336* of the required type(s) (in which case no memory will
337* be allocated). axes[] will contain the axis numbers
338* that were extracted, or 0 for newly created axes. The
339* vector length must be sufficient to contain all axis
340* numbers. No checks are performed to verify that the
341* coordinate axes are consistent, this is done by
342* wcsset().
343*
344* wcsdst struct wcsprm*
345* Struct describing the subimage. wcsprm::flag should
346* be set to -1 if wcsdst was not previously initialized
347* (memory leaks may result if it was previously
348* initialized).
349*
350* Function return value:
351* int Status return value:
352* 0: Success.
353* 1: Null wcsprm pointer passed.
354* 2: Memory allocation failed.
355* 12: Invalid subimage specification.
356* 13: Non-separable subimage coordinate system.
357*
358* For returns > 1, a detailed error message is set in
359* wcsprm::err if enabled, see wcserr_enable().
360*
361* Notes:
362* 1: Combinations of subimage axes of particular types may be extracted in
363* the same order as they occur in the input image by combining
364* preprocessor codes, for example
365*
366= *nsub = 1;
367= axes[0] = WCSSUB_LONGITUDE | WCSSUB_LATITUDE | WCSSUB_SPECTRAL;
368*
369* would extract the longitude, latitude, and spectral axes in the same
370* order as the input image. If one of each were present, *nsub = 3 would
371* be returned.
372*
373* For convenience, WCSSUB_CELESTIAL is defined as the combination
374* WCSSUB_LONGITUDE | WCSSUB_LATITUDE | WCSSUB_CUBEFACE.
375*
376* The codes may also be negated to extract all but the types specified,
377* for example
378*
379= *nsub = 4;
380= axes[0] = WCSSUB_LONGITUDE;
381= axes[1] = WCSSUB_LATITUDE;
382= axes[2] = WCSSUB_CUBEFACE;
383= axes[3] = -(WCSSUB_SPECTRAL | WCSSUB_STOKES);
384*
385* The last of these specifies all axis types other than spectral or
386* Stokes. Extraction is done in the order specified by axes[] a
387* longitude axis (if present) would be extracted first (via axes[0]) and
388* not subsequently (via axes[3]). Likewise for the latitude and cubeface
389* axes in this example.
390*
391* From the foregoing, it is apparent that the value of *nsub returned may
392* be less than or greater than that given. However, it will never exceed
393* the number of axes in the input image (plus the number of newly-created
394* axes if any were specified on input).
395*
396*
397* wcscompare() - Compare two wcsprm structs for equality
398* ------------------------------------------------------
399* wcscompare() compares two wcsprm structs for equality.
400*
401* Given:
402* cmp int A bit field controlling the strictness of the
403* comparison. When 0, all fields must be identical.
404*
405* The following constants may be or'ed together to
406* relax the comparison:
407* WCSCOMPARE_ANCILLARY: Ignore ancillary keywords
408* that don't change the WCS transformation, such
409* as DATE-OBS or EQUINOX.
410* WCSCOMPARE_TILING: Ignore integral differences in
411* CRPIXja. This is the 'tiling' condition, where
412* two WCSes cover different regions of the same
413* map projection and align on the same map grid.
414* WCSCOMPARE_CRPIX: Ignore any differences at all in
415* CRPIXja. The two WCSes cover different regions
416* of the same map projection but may not align on
417* the same map grid. Overrides WCSCOMPARE_TILING.
418*
419* tol double Tolerance for comparison of floating-point values.
420* For example, for tol == 1e-6, all floating-point
421* values in the structs must be equal to the first 6
422* decimal places. A value of 0 implies exact equality.
423*
424* wcs1 const struct wcsprm*
425* The first wcsprm struct to compare.
426*
427* wcs2 const struct wcsprm*
428* The second wcsprm struct to compare.
429*
430* Returned:
431* equal int* Non-zero when the given structs are equal.
432*
433* Function return value:
434* int Status return value:
435* 0: Success.
436* 1: Null pointer passed.
437*
438*
439* wcscopy() macro - Copy routine for the wcsprm struct
440* ----------------------------------------------------
441* wcscopy() does a deep copy of one wcsprm struct to another. As of
442* WCSLIB 3.6, it is implemented as a preprocessor macro that invokes
443* wcssub() with the nsub and axes pointers both set to zero.
444*
445*
446* wcsfree() - Destructor for the wcsprm struct
447* --------------------------------------------
448* wcsfree() frees memory allocated for the wcsprm arrays by wcsinit() and/or
449* wcsset(). wcsinit() records the memory it allocates and wcsfree() will only
450* attempt to free this.
451*
452* PLEASE NOTE: wcsfree() must not be invoked on a wcsprm struct that was not
453* initialized by wcsinit().
454*
455* Given and returned:
456* wcs struct wcsprm*
457* Coordinate transformation parameters.
458*
459* Function return value:
460* int Status return value:
461* 0: Success.
462* 1: Null wcsprm pointer passed.
463*
464*
465* wcstrim() - Free unused arrays in the wcsprm struct
466* ---------------------------------------------------
467* wcstrim() frees memory allocated by wcsinit() for arrays in the wcsprm
468* struct that remains unused after it has been set up by wcsset().
469*
470* The free'd array members are associated with FITS WCS keyrecords that are
471* rarely used and usually just bloat the struct: wcsprm::crota, wcsprm::colax,
472* wcsprm::cname, wcsprm::crder, wcsprm::csyer, wcsprm::czphs, and
473* wcsprm::cperi. If unused, wcsprm::pv, wcsprm::ps, and wcsprm::cd are also
474* freed.
475*
476* Once these arrays have been freed, a test such as
477=
478= if (!undefined(wcs->cname[i])) {...}
479=
480* must be protected as follows
481=
482= if (wcs->cname && !undefined(wcs->cname[i])) {...}
483=
484* In addition, if wcsprm::npv is non-zero but less than wcsprm::npvmax, then
485* the unused space in wcsprm::pv will be recovered (using realloc()).
486* Likewise for wcsprm::ps.
487*
488* Given and returned:
489* wcs struct wcsprm*
490* Coordinate transformation parameters.
491*
492* Function return value:
493* int Status return value:
494* 0: Success.
495* 1: Null wcsprm pointer passed.
496* 14: wcsprm struct is unset.
497*
498*
499* wcssize() - Compute the size of a wcsprm struct
500* -----------------------------------------------
501* wcssize() computes the full size of a wcsprm struct, including allocated
502* memory.
503*
504* Given:
505* wcs const struct wcsprm*
506* Coordinate transformation parameters.
507*
508* If NULL, the base size of the struct and the allocated
509* size are both set to zero.
510*
511* Returned:
512* sizes int[2] The first element is the base size of the struct as
513* returned by sizeof(struct wcsprm). The second element
514* is the total allocated size, in bytes, assuming that
515* the allocation was done by wcsini(). This figure
516* includes memory allocated for members of constituent
517* structs, such as wcsprm::lin.
518*
519* It is not an error for the struct not to have been set
520* up via wcsset(), which normally results in additional
521* memory allocation.
522*
523* Function return value:
524* int Status return value:
525* 0: Success.
526*
527*
528* auxsize() - Compute the size of a auxprm struct
529* -----------------------------------------------
530* auxsize() computes the full size of an auxprm struct, including allocated
531* memory.
532*
533* Given:
534* aux const struct auxprm*
535* Auxiliary coordinate information.
536*
537* If NULL, the base size of the struct and the allocated
538* size are both set to zero.
539*
540* Returned:
541* sizes int[2] The first element is the base size of the struct as
542* returned by sizeof(struct auxprm). The second element
543* is the total allocated size, in bytes, currently zero.
544*
545* Function return value:
546* int Status return value:
547* 0: Success.
548*
549*
550* wcsprt() - Print routine for the wcsprm struct
551* ----------------------------------------------
552* wcsprt() prints the contents of a wcsprm struct using wcsprintf(). Mainly
553* intended for diagnostic purposes.
554*
555* Given:
556* wcs const struct wcsprm*
557* Coordinate transformation parameters.
558*
559* Function return value:
560* int Status return value:
561* 0: Success.
562* 1: Null wcsprm pointer passed.
563*
564*
565* wcsperr() - Print error messages from a wcsprm struct
566* -----------------------------------------------------
567* wcsperr() prints the error message(s), if any, stored in a wcsprm struct,
568* and the linprm, celprm, prjprm, spcprm, and tabprm structs that it contains.
569* If there are no errors then nothing is printed. It uses wcserr_prt(), q.v.
570*
571* Given:
572* wcs const struct wcsprm*
573* Coordinate transformation parameters.
574*
575* prefix const char *
576* If non-NULL, each output line will be prefixed with
577* this string.
578*
579* Function return value:
580* int Status return value:
581* 0: Success.
582* 1: Null wcsprm pointer passed.
583*
584*
585* wcsbchk() - Enable/disable bounds checking
586* ------------------------------------------
587* wcsbchk() is used to control bounds checking in the projection routines.
588* Note that wcsset() always enables bounds checking. wcsbchk() will invoke
589* wcsset() on the wcsprm struct beforehand if necessary.
590*
591* Given and returned:
592* wcs struct wcsprm*
593* Coordinate transformation parameters.
594*
595* Given:
596* bounds int If bounds&1 then enable strict bounds checking for the
597* spherical-to-Cartesian (s2x) transformation for the
598* AZP, SZP, TAN, SIN, ZPN, and COP projections.
599*
600* If bounds&2 then enable strict bounds checking for the
601* Cartesian-to-spherical (x2s) transformation for the
602* HPX and XPH projections.
603*
604* If bounds&4 then enable bounds checking on the native
605* coordinates returned by the Cartesian-to-spherical
606* (x2s) transformations using prjchk().
607*
608* Zero it to disable all checking.
609*
610* Function return value:
611* int Status return value:
612* 0: Success.
613* 1: Null wcsprm pointer passed.
614*
615*
616* wcsset() - Setup routine for the wcsprm struct
617* ----------------------------------------------
618* wcsset() sets up a wcsprm struct according to information supplied within
619* it (refer to the description of the wcsprm struct).
620*
621* wcsset() recognizes the NCP projection and converts it to the equivalent SIN
622* projection and likewise translates GLS into SFL. It also translates the
623* AIPS spectral types ('FREQ-LSR', 'FELO-HEL', etc.), possibly changing the
624* input header keywords wcsprm::ctype and/or wcsprm::specsys if necessary.
625*
626* Note that this routine need not be called directly; it will be invoked by
627* wcsp2s() and wcss2p() if the wcsprm::flag is anything other than a
628* predefined magic value.
629*
630* Given and returned:
631* wcs struct wcsprm*
632* Coordinate transformation parameters.
633*
634* Function return value:
635* int Status return value:
636* 0: Success.
637* 1: Null wcsprm pointer passed.
638* 2: Memory allocation failed.
639* 3: Linear transformation matrix is singular.
640* 4: Inconsistent or unrecognized coordinate axis
641* types.
642* 5: Invalid parameter value.
643* 6: Invalid coordinate transformation parameters.
644* 7: Ill-conditioned coordinate transformation
645* parameters.
646*
647* For returns > 1, a detailed error message is set in
648* wcsprm::err if enabled, see wcserr_enable().
649*
650* Notes:
651* 1: wcsset() always enables strict bounds checking in the projection
652* routines (via a call to prjini()). Use wcsbchk() to modify
653* bounds-checking after wcsset() is invoked.
654*
655*
656* wcsp2s() - Pixel-to-world transformation
657* ----------------------------------------
658* wcsp2s() transforms pixel coordinates to world coordinates.
659*
660* Given and returned:
661* wcs struct wcsprm*
662* Coordinate transformation parameters.
663*
664* Given:
665* ncoord,
666* nelem int The number of coordinates, each of vector length
667* nelem but containing wcs.naxis coordinate elements.
668* Thus nelem must equal or exceed the value of the
669* NAXIS keyword unless ncoord == 1, in which case nelem
670* is not used.
671*
672* pixcrd const double[ncoord][nelem]
673* Array of pixel coordinates.
674*
675* Returned:
676* imgcrd double[ncoord][nelem]
677* Array of intermediate world coordinates. For
678* celestial axes, imgcrd[][wcs.lng] and
679* imgcrd[][wcs.lat] are the projected x-, and
680* y-coordinates in pseudo "degrees". For spectral
681* axes, imgcrd[][wcs.spec] is the intermediate spectral
682* coordinate, in SI units. For time axes,
683* imgcrd[][wcs.time] is the intermediate time
684* coordinate.
685*
686* phi,theta double[ncoord]
687* Longitude and latitude in the native coordinate system
688* of the projection [deg].
689*
690* world double[ncoord][nelem]
691* Array of world coordinates. For celestial axes,
692* world[][wcs.lng] and world[][wcs.lat] are the
693* celestial longitude and latitude [deg]. For spectral
694* axes, world[][wcs.spec] is the spectral coordinate, in
695* SI units. For time axes, world[][wcs.time] is the
696* time coordinate.
697*
698* stat int[ncoord]
699* Status return value for each coordinate:
700* 0: Success.
701* 1+: A bit mask indicating invalid pixel coordinate
702* element(s).
703*
704* Function return value:
705* int Status return value:
706* 0: Success.
707* 1: Null wcsprm pointer passed.
708* 2: Memory allocation failed.
709* 3: Linear transformation matrix is singular.
710* 4: Inconsistent or unrecognized coordinate axis
711* types.
712* 5: Invalid parameter value.
713* 6: Invalid coordinate transformation parameters.
714* 7: Ill-conditioned coordinate transformation
715* parameters.
716* 8: One or more of the pixel coordinates were
717* invalid, as indicated by the stat vector.
718*
719* For returns > 1, a detailed error message is set in
720* wcsprm::err if enabled, see wcserr_enable().
721*
722*
723* wcss2p() - World-to-pixel transformation
724* ----------------------------------------
725* wcss2p() transforms world coordinates to pixel coordinates.
726*
727* Given and returned:
728* wcs struct wcsprm*
729* Coordinate transformation parameters.
730*
731* Given:
732* ncoord,
733* nelem int The number of coordinates, each of vector length nelem
734* but containing wcs.naxis coordinate elements. Thus
735* nelem must equal or exceed the value of the NAXIS
736* keyword unless ncoord == 1, in which case nelem is not
737* used.
738*
739* world const double[ncoord][nelem]
740* Array of world coordinates. For celestial axes,
741* world[][wcs.lng] and world[][wcs.lat] are the
742* celestial longitude and latitude [deg]. For spectral
743* axes, world[][wcs.spec] is the spectral coordinate, in
744* SI units. For time axes, world[][wcs.time] is the
745* time coordinate.
746*
747* Returned:
748* phi,theta double[ncoord]
749* Longitude and latitude in the native coordinate
750* system of the projection [deg].
751*
752* imgcrd double[ncoord][nelem]
753* Array of intermediate world coordinates. For
754* celestial axes, imgcrd[][wcs.lng] and
755* imgcrd[][wcs.lat] are the projected x-, and
756* y-coordinates in pseudo "degrees". For quadcube
757* projections with a CUBEFACE axis the face number is
758* also returned in imgcrd[][wcs.cubeface]. For
759* spectral axes, imgcrd[][wcs.spec] is the intermediate
760* spectral coordinate, in SI units. For time axes,
761* imgcrd[][wcs.time] is the intermediate time
762* coordinate.
763*
764* pixcrd double[ncoord][nelem]
765* Array of pixel coordinates.
766*
767* stat int[ncoord]
768* Status return value for each coordinate:
769* 0: Success.
770* 1+: A bit mask indicating invalid world coordinate
771* element(s).
772*
773* Function return value:
774* int Status return value:
775* 0: Success.
776* 1: Null wcsprm pointer passed.
777* 2: Memory allocation failed.
778* 3: Linear transformation matrix is singular.
779* 4: Inconsistent or unrecognized coordinate axis
780* types.
781* 5: Invalid parameter value.
782* 6: Invalid coordinate transformation parameters.
783* 7: Ill-conditioned coordinate transformation
784* parameters.
785* 9: One or more of the world coordinates were
786* invalid, as indicated by the stat vector.
787*
788* For returns > 1, a detailed error message is set in
789* wcsprm::err if enabled, see wcserr_enable().
790*
791*
792* wcsmix() - Hybrid coordinate transformation
793* -------------------------------------------
794* wcsmix(), given either the celestial longitude or latitude plus an element
795* of the pixel coordinate, solves for the remaining elements by iterating on
796* the unknown celestial coordinate element using wcss2p(). Refer also to the
797* notes below.
798*
799* Given and returned:
800* wcs struct wcsprm*
801* Indices for the celestial coordinates obtained
802* by parsing the wcsprm::ctype[].
803*
804* Given:
805* mixpix int Which element of the pixel coordinate is given.
806*
807* mixcel int Which element of the celestial coordinate is given:
808* 1: Celestial longitude is given in
809* world[wcs.lng], latitude returned in
810* world[wcs.lat].
811* 2: Celestial latitude is given in
812* world[wcs.lat], longitude returned in
813* world[wcs.lng].
814*
815* vspan const double[2]
816* Solution interval for the celestial coordinate [deg].
817* The ordering of the two limits is irrelevant.
818* Longitude ranges may be specified with any convenient
819* normalization, for example [-120,+120] is the same as
820* [240,480], except that the solution will be returned
821* with the same normalization, i.e. lie within the
822* interval specified.
823*
824* vstep const double
825* Step size for solution search [deg]. If zero, a
826* sensible, although perhaps non-optimal default will be
827* used.
828*
829* viter int If a solution is not found then the step size will be
830* halved and the search recommenced. viter controls how
831* many times the step size is halved. The allowed range
832* is 5 - 10.
833*
834* Given and returned:
835* world double[naxis]
836* World coordinate elements. world[wcs.lng] and
837* world[wcs.lat] are the celestial longitude and
838* latitude [deg]. Which is given and which returned
839* depends on the value of mixcel. All other elements
840* are given.
841*
842* Returned:
843* phi,theta double[naxis]
844* Longitude and latitude in the native coordinate
845* system of the projection [deg].
846*
847* imgcrd double[naxis]
848* Image coordinate elements. imgcrd[wcs.lng] and
849* imgcrd[wcs.lat] are the projected x-, and
850* y-coordinates in pseudo "degrees".
851*
852* Given and returned:
853* pixcrd double[naxis]
854* Pixel coordinate. The element indicated by mixpix is
855* given and the remaining elements are returned.
856*
857* Function return value:
858* int Status return value:
859* 0: Success.
860* 1: Null wcsprm pointer passed.
861* 2: Memory allocation failed.
862* 3: Linear transformation matrix is singular.
863* 4: Inconsistent or unrecognized coordinate axis
864* types.
865* 5: Invalid parameter value.
866* 6: Invalid coordinate transformation parameters.
867* 7: Ill-conditioned coordinate transformation
868* parameters.
869* 10: Invalid world coordinate.
870* 11: No solution found in the specified interval.
871*
872* For returns > 1, a detailed error message is set in
873* wcsprm::err if enabled, see wcserr_enable().
874*
875* Notes:
876* 1: Initially the specified solution interval is checked to see if it's a
877* "crossing" interval. If it isn't, a search is made for a crossing
878* solution by iterating on the unknown celestial coordinate starting at
879* the upper limit of the solution interval and decrementing by the
880* specified step size. A crossing is indicated if the trial value of the
881* pixel coordinate steps through the value specified. If a crossing
882* interval is found then the solution is determined by a modified form of
883* "regula falsi" division of the crossing interval. If no crossing
884* interval was found within the specified solution interval then a search
885* is made for a "non-crossing" solution as may arise from a point of
886* tangency. The process is complicated by having to make allowance for
887* the discontinuities that occur in all map projections.
888*
889* Once one solution has been determined others may be found by subsequent
890* invokations of wcsmix() with suitably restricted solution intervals.
891*
892* Note the circumstance that arises when the solution point lies at a
893* native pole of a projection in which the pole is represented as a
894* finite curve, for example the zenithals and conics. In such cases two
895* or more valid solutions may exist but wcsmix() only ever returns one.
896*
897* Because of its generality wcsmix() is very compute-intensive. For
898* compute-limited applications more efficient special-case solvers could
899* be written for simple projections, for example non-oblique cylindrical
900* projections.
901*
902*
903* wcsccs() - Change celestial coordinate system
904* ---------------------------------------------
905* wcsccs() changes the celestial coordinate system of a wcsprm struct. For
906* example, from equatorial to galactic coordinates.
907*
908* Parameters that define the spherical coordinate transformation, essentially
909* being three Euler angles, must be provided. Thereby wcsccs() does not need
910* prior knowledge of specific celestial coordinate systems. It also has the
911* advantage of making it completely general.
912*
913* Auxiliary members of the wcsprm struct relating to equatorial celestial
914* coordinate systems may also be changed.
915*
916* Only orthodox spherical coordinate systems are supported. That is, they
917* must be right-handed, with latitude increasing from zero at the equator to
918* +90 degrees at the pole. This precludes systems such as aziumuth and zenith
919* distance, which, however, could be handled as negative azimuth and
920* elevation.
921*
922* PLEASE NOTE: Information in the wcsprm struct relating to the original
923* coordinate system will be overwritten and therefore lost. If this is
924* undesirable, invoke wcsccs() on a copy of the struct made with wcssub().
925* The wcsprm struct is reset on return with an explicit call to wcsset().
926*
927* Given and returned:
928* wcs struct wcsprm*
929* Coordinate transformation parameters. Particular
930* "values to be given" elements of the wcsprm struct
931* are modified.
932*
933* Given:
934* lng2p1,
935* lat2p1 double Longitude and latitude in the new celestial coordinate
936* system of the pole (i.e. latitude +90) of the original
937* system [deg]. See notes 1 and 2 below.
938*
939* lng1p2 double Longitude in the original celestial coordinate system
940* of the pole (i.e. latitude +90) of the new system
941* [deg]. See note 1 below.
942*
943* clng,clat const char*
944* Longitude and latitude identifiers of the new CTYPEia
945* celestial axis codes, without trailing dashes. For
946* example, "RA" and "DEC" or "GLON" and "GLAT". Up to
947* four characters are used, longer strings need not be
948* null-terminated.
949*
950* radesys const char*
951* Used when transforming to equatorial coordinates,
952* identified by clng == "RA" and clat = "DEC". May be
953* set to the null pointer to preserve the current value.
954* Up to 71 characters are used, longer strings need not
955* be null-terminated.
956*
957* If the new coordinate system is anything other than
958* equatorial, then wcsprm::radesys will be cleared.
959*
960* equinox double Used when transforming to equatorial coordinates. May
961* be set to zero to preserve the current value.
962*
963* If the new coordinate system is not equatorial, then
964* wcsprm::equinox will be marked as undefined.
965*
966* alt const char*
967* Character code for alternate coordinate descriptions
968* (i.e. the 'a' in keyword names such as CTYPEia). This
969* is blank for the primary coordinate description, or
970* one of the 26 upper-case letters, A-Z. May be set to
971* the null pointer, or null string if no change is
972* required.
973*
974* Function return value:
975* int Status return value:
976* 0: Success.
977* 1: Null wcsprm pointer passed.
978* 12: Invalid subimage specification (no celestial
979* axes).
980*
981* Notes:
982* 1: Follows the prescription given in WCS Paper II, Sect. 2.7 for changing
983* celestial coordinates.
984*
985* The implementation takes account of indeterminacies that arise in that
986* prescription in the particular cases where one of the poles of the new
987* system is at the fiducial point, or one of them is at the native pole.
988*
989* 2: If lat2p1 == +90, i.e. where the poles of the two coordinate systems
990* coincide, then the spherical coordinate transformation becomes a simple
991* change in origin of longitude given by
992* lng2 = lng1 + (lng2p1 - lng1p2 - 180), and lat2 = lat1, where
993* (lng2,lat2) are coordinates in the new system, and (lng1,lat1) are
994* coordinates in the original system.
995*
996* Likewise, if lat2p1 == -90, then lng2 = -lng1 + (lng2p1 + lng1p2), and
997* lat2 = -lat1.
998*
999* 3: For example, if the original coordinate system is B1950 equatorial and
1000* the desired new coordinate system is galactic, then
1001*
1002* - (lng2p1,lat2p1) are the galactic coordinates of the B1950 celestial
1003* pole, defined by the IAU to be (123.0,+27.4), and lng1p2 is the B1950
1004* right ascension of the galactic pole, defined as 192.25. Clearly
1005* these coordinates are fixed for a particular coordinate
1006* transformation.
1007*
1008* - (clng,clat) would be 'GLON' and 'GLAT', these being the FITS standard
1009* identifiers for galactic coordinates.
1010*
1011* - Since the new coordinate system is not equatorial, wcsprm::radesys
1012* and wcsprm::equinox will be cleared.
1013*
1014* 4. The coordinates required for some common transformations (obtained from
1015* https://ned.ipac.caltech.edu/coordinate_calculator) are as follows:
1016*
1017= (123.0000,+27.4000) galactic coordinates of B1950 celestial pole,
1018= (192.2500,+27.4000) B1950 equatorial coordinates of galactic pole.
1019*
1020= (122.9319,+27.1283) galactic coordinates of J2000 celestial pole,
1021= (192.8595,+27.1283) J2000 equatorial coordinates of galactic pole.
1022*
1023= (359.6774,+89.7217) B1950 equatorial coordinates of J2000 pole,
1024= (180.3162,+89.7217) J2000 equatorial coordinates of B1950 pole.
1025*
1026= (270.0000,+66.5542) B1950 equatorial coordinates of B1950 ecliptic pole,
1027= ( 90.0000,+66.5542) B1950 ecliptic coordinates of B1950 celestial pole.
1028*
1029= (270.0000,+66.5607) J2000 equatorial coordinates of J2000 ecliptic pole,
1030= ( 90.0000,+66.5607) J2000 ecliptic coordinates of J2000 celestial pole.
1031*
1032= ( 26.7315,+15.6441) supergalactic coordinates of B1950 celestial pole,
1033= (283.1894,+15.6441) B1950 equatorial coordinates of supergalactic pole.
1034*
1035= ( 26.4505,+15.7089) supergalactic coordinates of J2000 celestial pole,
1036= (283.7542,+15.7089) J2000 equatorial coordinates of supergalactic pole.
1037*
1038*
1039* wcssptr() - Spectral axis translation
1040* -------------------------------------
1041* wcssptr() translates the spectral axis in a wcsprm struct. For example, a
1042* 'FREQ' axis may be translated into 'ZOPT-F2W' and vice versa.
1043*
1044* PLEASE NOTE: Information in the wcsprm struct relating to the original
1045* coordinate system will be overwritten and therefore lost. If this is
1046* undesirable, invoke wcssptr() on a copy of the struct made with wcssub().
1047* The wcsprm struct is reset on return with an explicit call to wcsset().
1048*
1049* Given and returned:
1050* wcs struct wcsprm*
1051* Coordinate transformation parameters.
1052*
1053* i int* Index of the spectral axis (0-relative). If given < 0
1054* it will be set to the first spectral axis identified
1055* from the ctype[] keyvalues in the wcsprm struct.
1056*
1057* ctype char[9] Desired spectral CTYPEia. Wildcarding may be used as
1058* for the ctypeS2 argument to spctrn() as described in
1059* the prologue of spc.h, i.e. if the final three
1060* characters are specified as "???", or if just the
1061* eighth character is specified as '?', the correct
1062* algorithm code will be substituted and returned.
1063*
1064* Function return value:
1065* int Status return value:
1066* 0: Success.
1067* 1: Null wcsprm pointer passed.
1068* 2: Memory allocation failed.
1069* 3: Linear transformation matrix is singular.
1070* 4: Inconsistent or unrecognized coordinate axis
1071* types.
1072* 5: Invalid parameter value.
1073* 6: Invalid coordinate transformation parameters.
1074* 7: Ill-conditioned coordinate transformation
1075* parameters.
1076* 12: Invalid subimage specification (no spectral
1077* axis).
1078*
1079* For returns > 1, a detailed error message is set in
1080* wcsprm::err if enabled, see wcserr_enable().
1081*
1082*
1083* wcslib_version() - WCSLIB version number
1084* ----------------------------------------
1085* wcslib_version() returns the WCSLIB version number.
1086*
1087* The major version number changes when the ABI changes or when the license
1088* conditions change. ABI changes typically result from a change to the
1089* contents of one of the structs. The major version number is used to
1090* distinguish between incompatible versions of the sharable library.
1091*
1092* The minor version number changes with new functionality or bug fixes that do
1093* not involve a change in the ABI.
1094*
1095* The auxiliary version number (which is often absent) signals changes to the
1096* documentation, test suite, build procedures, or any other change that does
1097* not affect the compiled library.
1098*
1099* Returned:
1100* vers[3] int[3] The broken-down version number:
1101* 0: Major version number.
1102* 1: Minor version number.
1103* 2: Auxiliary version number (zero if absent).
1104* May be given as a null pointer if not required.
1105*
1106* Function return value:
1107* char* A null-terminated, statically allocated string
1108* containing the version number in the usual form, i.e.
1109* "<major>.<minor>.<auxiliary>".
1110*
1111*
1112* wcsprm struct - Coordinate transformation parameters
1113* ----------------------------------------------------
1114* The wcsprm struct contains information required to transform world
1115* coordinates. It consists of certain members that must be set by the user
1116* ("given") and others that are set by the WCSLIB routines ("returned").
1117* While the addresses of the arrays themselves may be set by wcsinit() if it
1118* (optionally) allocates memory, their contents must be set by the user.
1119*
1120* Some parameters that are given are not actually required for transforming
1121* coordinates. These are described as "auxiliary"; the struct simply provides
1122* a place to store them, though they may be used by wcshdo() in constructing a
1123* FITS header from a wcsprm struct. Some of the returned values are supplied
1124* for informational purposes and others are for internal use only as
1125* indicated.
1126*
1127* In practice, it is expected that a WCS parser would scan the FITS header to
1128* determine the number of coordinate axes. It would then use wcsinit() to
1129* allocate memory for arrays in the wcsprm struct and set default values.
1130* Then as it reread the header and identified each WCS keyrecord it would load
1131* the value into the relevant wcsprm array element. This is essentially what
1132* wcspih() does - refer to the prologue of wcshdr.h. As the final step,
1133* wcsset() is invoked, either directly or indirectly, to set the derived
1134* members of the wcsprm struct. wcsset() strips off trailing blanks in all
1135* string members and null-fills the character array.
1136*
1137* int flag
1138* (Given and returned) This flag must be set to zero whenever any of the
1139* following wcsprm struct members are set or changed:
1140*
1141* - wcsprm::naxis (q.v., not normally set by the user),
1142* - wcsprm::crpix,
1143* - wcsprm::pc,
1144* - wcsprm::cdelt,
1145* - wcsprm::crval,
1146* - wcsprm::cunit,
1147* - wcsprm::ctype,
1148* - wcsprm::lonpole,
1149* - wcsprm::latpole,
1150* - wcsprm::restfrq,
1151* - wcsprm::restwav,
1152* - wcsprm::npv,
1153* - wcsprm::pv,
1154* - wcsprm::nps,
1155* - wcsprm::ps,
1156* - wcsprm::cd,
1157* - wcsprm::crota,
1158* - wcsprm::altlin,
1159* - wcsprm::ntab,
1160* - wcsprm::nwtb,
1161* - wcsprm::tab,
1162* - wcsprm::wtb.
1163*
1164* This signals the initialization routine, wcsset(), to recompute the
1165* returned members of the linprm, celprm, spcprm, and tabprm structs.
1166* wcsset() will reset flag to indicate that this has been done.
1167*
1168* PLEASE NOTE: flag should be set to -1 when wcsinit() is called for the
1169* first time for a particular wcsprm struct in order to initialize memory
1170* management. It must ONLY be used on the first initialization otherwise
1171* memory leaks may result.
1172*
1173* int naxis
1174* (Given or returned) Number of pixel and world coordinate elements.
1175*
1176* If wcsinit() is used to initialize the linprm struct (as would normally
1177* be the case) then it will set naxis from the value passed to it as a
1178* function argument. The user should not subsequently modify it.
1179*
1180* double *crpix
1181* (Given) Address of the first element of an array of double containing
1182* the coordinate reference pixel, CRPIXja.
1183*
1184* double *pc
1185* (Given) Address of the first element of the PCi_ja (pixel coordinate)
1186* transformation matrix. The expected order is
1187*
1188= struct wcsprm wcs;
1189= wcs.pc = {PC1_1, PC1_2, PC2_1, PC2_2};
1190*
1191* This may be constructed conveniently from a 2-D array via
1192*
1193= double m[2][2] = {{PC1_1, PC1_2},
1194= {PC2_1, PC2_2}};
1195*
1196* which is equivalent to
1197*
1198= double m[2][2];
1199= m[0][0] = PC1_1;
1200= m[0][1] = PC1_2;
1201= m[1][0] = PC2_1;
1202= m[1][1] = PC2_2;
1203*
1204* The storage order for this 2-D array is the same as for the 1-D array,
1205* whence
1206*
1207= wcs.pc = *m;
1208*
1209* would be legitimate.
1210*
1211* double *cdelt
1212* (Given) Address of the first element of an array of double containing
1213* the coordinate increments, CDELTia.
1214*
1215* double *crval
1216* (Given) Address of the first element of an array of double containing
1217* the coordinate reference values, CRVALia.
1218*
1219* char (*cunit)[72]
1220* (Given) Address of the first element of an array of char[72] containing
1221* the CUNITia keyvalues which define the units of measurement of the
1222* CRVALia, CDELTia, and CDi_ja keywords.
1223*
1224* As CUNITia is an optional header keyword, cunit[][72] may be left blank
1225* but otherwise is expected to contain a standard units specification as
1226* defined by WCS Paper I. Utility function wcsutrn(), described in
1227* wcsunits.h, is available to translate commonly used non-standard units
1228* specifications but this must be done as a separate step before invoking
1229* wcsset().
1230*
1231* For celestial axes, if cunit[][72] is not blank, wcsset() uses
1232* wcsunits() to parse it and scale cdelt[], crval[], and cd[][*] to
1233* degrees. It then resets cunit[][72] to "deg".
1234*
1235* For spectral axes, if cunit[][72] is not blank, wcsset() uses wcsunits()
1236* to parse it and scale cdelt[], crval[], and cd[][*] to SI units. It
1237* then resets cunit[][72] accordingly.
1238*
1239* wcsset() ignores cunit[][72] for other coordinate types; cunit[][72] may
1240* be used to label coordinate values.
1241*
1242* These variables accomodate the longest allowed string-valued FITS
1243* keyword, being limited to 68 characters, plus the null-terminating
1244* character.
1245*
1246* char (*ctype)[72]
1247* (Given) Address of the first element of an array of char[72] containing
1248* the coordinate axis types, CTYPEia.
1249*
1250* The ctype[][72] keyword values must be in upper case and there must be
1251* zero or one pair of matched celestial axis types, and zero or one
1252* spectral axis. The ctype[][72] strings should be padded with blanks on
1253* the right and null-terminated so that they are at least eight characters
1254* in length.
1255*
1256* These variables accomodate the longest allowed string-valued FITS
1257* keyword, being limited to 68 characters, plus the null-terminating
1258* character.
1259*
1260* double lonpole
1261* (Given and returned) The native longitude of the celestial pole, phi_p,
1262* given by LONPOLEa [deg] or by PVi_2a [deg] attached to the longitude
1263* axis which takes precedence if defined, and ...
1264* double latpole
1265* (Given and returned) ... the native latitude of the celestial pole,
1266* theta_p, given by LATPOLEa [deg] or by PVi_3a [deg] attached to the
1267* longitude axis which takes precedence if defined.
1268*
1269* lonpole and latpole may be left to default to values set by wcsinit()
1270* (see celprm::ref), but in any case they will be reset by wcsset() to
1271* the values actually used. Note therefore that if the wcsprm struct is
1272* reused without resetting them, whether directly or via wcsinit(), they
1273* will no longer have their default values.
1274*
1275* double restfrq
1276* (Given) The rest frequency [Hz], and/or ...
1277* double restwav
1278* (Given) ... the rest wavelength in vacuo [m], only one of which need be
1279* given, the other should be set to zero.
1280*
1281* int npv
1282* (Given) The number of entries in the wcsprm::pv[] array.
1283*
1284* int npvmax
1285* (Given or returned) The length of the wcsprm::pv[] array.
1286*
1287* npvmax will be set by wcsinit() if it allocates memory for wcsprm::pv[],
1288* otherwise it must be set by the user. See also wcsnpv().
1289*
1290* struct pvcard *pv
1291* (Given) Address of the first element of an array of length npvmax of
1292* pvcard structs.
1293*
1294* As a FITS header parser encounters each PVi_ma keyword it should load it
1295* into a pvcard struct in the array and increment npv. wcsset()
1296* interprets these as required.
1297*
1298* Note that, if they were not given, wcsset() resets the entries for
1299* PVi_1a, PVi_2a, PVi_3a, and PVi_4a for longitude axis i to match
1300* phi_0 and theta_0 (the native longitude and latitude of the reference
1301* point), LONPOLEa and LATPOLEa respectively.
1302*
1303* int nps
1304* (Given) The number of entries in the wcsprm::ps[] array.
1305*
1306* int npsmax
1307* (Given or returned) The length of the wcsprm::ps[] array.
1308*
1309* npsmax will be set by wcsinit() if it allocates memory for wcsprm::ps[],
1310* otherwise it must be set by the user. See also wcsnps().
1311*
1312* struct pscard *ps
1313* (Given) Address of the first element of an array of length npsmax of
1314* pscard structs.
1315*
1316* As a FITS header parser encounters each PSi_ma keyword it should load it
1317* into a pscard struct in the array and increment nps. wcsset()
1318* interprets these as required (currently no PSi_ma keyvalues are
1319* recognized).
1320*
1321* double *cd
1322* (Given) For historical compatibility, the wcsprm struct supports two
1323* alternate specifications of the linear transformation matrix, those
1324* associated with the CDi_ja keywords, and ...
1325* double *crota
1326* (Given) ... those associated with the CROTAi keywords. Although these
1327* may not formally co-exist with PCi_ja, the approach taken here is simply
1328* to ignore them if given in conjunction with PCi_ja.
1329*
1330* int altlin
1331* (Given) altlin is a bit flag that denotes which of the PCi_ja, CDi_ja
1332* and CROTAi keywords are present in the header:
1333*
1334* - Bit 0: PCi_ja is present.
1335*
1336* - Bit 1: CDi_ja is present.
1337*
1338* Matrix elements in the IRAF convention are equivalent to the product
1339* CDi_ja = CDELTia * PCi_ja, but the defaults differ from that of the
1340* PCi_ja matrix. If one or more CDi_ja keywords are present then all
1341* unspecified CDi_ja default to zero. If no CDi_ja (or CROTAi) keywords
1342* are present, then the header is assumed to be in PCi_ja form whether
1343* or not any PCi_ja keywords are present since this results in an
1344* interpretation of CDELTia consistent with the original FITS
1345* specification.
1346*
1347* While CDi_ja may not formally co-exist with PCi_ja, it may co-exist
1348* with CDELTia and CROTAi which are to be ignored.
1349*
1350* - Bit 2: CROTAi is present.
1351*
1352* In the AIPS convention, CROTAi may only be associated with the
1353* latitude axis of a celestial axis pair. It specifies a rotation in
1354* the image plane that is applied AFTER the CDELTia; any other CROTAi
1355* keywords are ignored.
1356*
1357* CROTAi may not formally co-exist with PCi_ja.
1358*
1359* CROTAi and CDELTia may formally co-exist with CDi_ja but if so are to
1360* be ignored.
1361*
1362* - Bit 3: PCi_ja + CDELTia was derived from CDi_ja by wcspcx().
1363*
1364* This bit is set by wcspcx() when it derives PCi_ja and CDELTia from
1365* CDi_ja via an orthonormal decomposition. In particular, it signals
1366* wcsset() not to replace PCi_ja by a copy of CDi_ja with CDELTia set
1367* to unity.
1368*
1369* CDi_ja and CROTAi keywords, if found, are to be stored in the wcsprm::cd
1370* and wcsprm::crota arrays which are dimensioned similarly to wcsprm::pc
1371* and wcsprm::cdelt. FITS header parsers should use the following
1372* procedure:
1373*
1374* - Whenever a PCi_ja keyword is encountered: altlin |= 1;
1375*
1376* - Whenever a CDi_ja keyword is encountered: altlin |= 2;
1377*
1378* - Whenever a CROTAi keyword is encountered: altlin |= 4;
1379*
1380* If none of these bits are set the PCi_ja representation results, i.e.
1381* wcsprm::pc and wcsprm::cdelt will be used as given.
1382*
1383* These alternate specifications of the linear transformation matrix are
1384* translated immediately to PCi_ja by wcsset() and are invisible to the
1385* lower-level WCSLIB routines. In particular, unless bit 3 is also set,
1386* wcsset() resets wcsprm::cdelt to unity if CDi_ja is present (and no
1387* PCi_ja).
1388*
1389* If CROTAi are present but none is associated with the latitude axis
1390* (and no PCi_ja or CDi_ja), then wcsset() reverts to a unity PCi_ja
1391* matrix.
1392*
1393* int velref
1394* (Given) AIPS velocity code VELREF, refer to spcaips().
1395*
1396* It is not necessary to reset the wcsprm struct (via wcsset()) when
1397* wcsprm::velref is changed.
1398*
1399* char alt[4]
1400* (Given, auxiliary) Character code for alternate coordinate descriptions
1401* (i.e. the 'a' in keyword names such as CTYPEia). This is blank for the
1402* primary coordinate description, or one of the 26 upper-case letters,
1403* A-Z.
1404*
1405* An array of four characters is provided for alignment purposes, only the
1406* first is used.
1407*
1408* It is not necessary to reset the wcsprm struct (via wcsset()) when
1409* wcsprm::alt is changed.
1410*
1411* int colnum
1412* (Given, auxiliary) Where the coordinate representation is associated
1413* with an image-array column in a FITS binary table, this variable may be
1414* used to record the relevant column number.
1415*
1416* It should be set to zero for an image header or pixel list.
1417*
1418* It is not necessary to reset the wcsprm struct (via wcsset()) when
1419* wcsprm::colnum is changed.
1420*
1421* int *colax
1422* (Given, auxiliary) Address of the first element of an array of int
1423* recording the column numbers for each axis in a pixel list.
1424*
1425* The array elements should be set to zero for an image header or image
1426* array in a binary table.
1427*
1428* It is not necessary to reset the wcsprm struct (via wcsset()) when
1429* wcsprm::colax is changed.
1430*
1431* char (*cname)[72]
1432* (Given, auxiliary) The address of the first element of an array of
1433* char[72] containing the coordinate axis names, CNAMEia.
1434*
1435* These variables accomodate the longest allowed string-valued FITS
1436* keyword, being limited to 68 characters, plus the null-terminating
1437* character.
1438*
1439* It is not necessary to reset the wcsprm struct (via wcsset()) when
1440* wcsprm::cname is changed.
1441*
1442* double *crder
1443* (Given, auxiliary) Address of the first element of an array of double
1444* recording the random error in the coordinate value, CRDERia.
1445*
1446* It is not necessary to reset the wcsprm struct (via wcsset()) when
1447* wcsprm::crder is changed.
1448*
1449* double *csyer
1450* (Given, auxiliary) Address of the first element of an array of double
1451* recording the systematic error in the coordinate value, CSYERia.
1452*
1453* It is not necessary to reset the wcsprm struct (via wcsset()) when
1454* wcsprm::csyer is changed.
1455*
1456* double *czphs
1457* (Given, auxiliary) Address of the first element of an array of double
1458* recording the time at the zero point of a phase axis, CZPHSia.
1459*
1460* It is not necessary to reset the wcsprm struct (via wcsset()) when
1461* wcsprm::czphs is changed.
1462*
1463* double *cperi
1464* (Given, auxiliary) Address of the first element of an array of double
1465* recording the period of a phase axis, CPERIia.
1466*
1467* It is not necessary to reset the wcsprm struct (via wcsset()) when
1468* wcsprm::cperi is changed.
1469*
1470* char wcsname[72]
1471* (Given, auxiliary) The name given to the coordinate representation,
1472* WCSNAMEa. This variable accomodates the longest allowed string-valued
1473* FITS keyword, being limited to 68 characters, plus the null-terminating
1474* character.
1475*
1476* It is not necessary to reset the wcsprm struct (via wcsset()) when
1477* wcsprm::wcsname is changed.
1478*
1479* char timesys[72]
1480* (Given, auxiliary) TIMESYS keyvalue, being the time scale (UTC, TAI,
1481* etc.) in which all other time-related auxiliary header values are
1482* recorded. Also defines the time scale for an image axis with CTYPEia
1483* set to 'TIME'.
1484*
1485* It is not necessary to reset the wcsprm struct (via wcsset()) when
1486* wcsprm::timesys is changed.
1487*
1488* char trefpos[72]
1489* (Given, auxiliary) TREFPOS keyvalue, being the location in space where
1490* the recorded time is valid.
1491*
1492* It is not necessary to reset the wcsprm struct (via wcsset()) when
1493* wcsprm::trefpos is changed.
1494*
1495* char trefdir[72]
1496* (Given, auxiliary) TREFDIR keyvalue, being the reference direction used
1497* in calculating a pathlength delay.
1498*
1499* It is not necessary to reset the wcsprm struct (via wcsset()) when
1500* wcsprm::trefdir is changed.
1501*
1502* char plephem[72]
1503* (Given, auxiliary) PLEPHEM keyvalue, being the Solar System ephemeris
1504* used for calculating a pathlength delay.
1505*
1506* It is not necessary to reset the wcsprm struct (via wcsset()) when
1507* wcsprm::plephem is changed.
1508*
1509* char timeunit[72]
1510* (Given, auxiliary) TIMEUNIT keyvalue, being the time units in which
1511* the following header values are expressed: TSTART, TSTOP, TIMEOFFS,
1512* TIMSYER, TIMRDER, TIMEDEL. It also provides the default value for
1513* CUNITia for time axes.
1514*
1515* It is not necessary to reset the wcsprm struct (via wcsset()) when
1516* wcsprm::timeunit is changed.
1517*
1518* char dateref[72]
1519* (Given, auxiliary) DATEREF keyvalue, being the date of a reference epoch
1520* relative to which other time measurements refer.
1521*
1522* It is not necessary to reset the wcsprm struct (via wcsset()) when
1523* wcsprm::dateref is changed.
1524*
1525* double mjdref[2]
1526* (Given, auxiliary) MJDREF keyvalue, equivalent to DATEREF expressed as
1527* a Modified Julian Date (MJD = JD - 2400000.5). The value is given as
1528* the sum of the two-element vector, allowing increased precision.
1529*
1530* It is not necessary to reset the wcsprm struct (via wcsset()) when
1531* wcsprm::mjdref is changed.
1532*
1533* double timeoffs
1534* (Given, auxiliary) TIMEOFFS keyvalue, being a time offset, which may be
1535* used, for example, to provide a uniform clock correction for times
1536* referenced to DATEREF.
1537*
1538* It is not necessary to reset the wcsprm struct (via wcsset()) when
1539* wcsprm::timeoffs is changed.
1540*
1541* char dateobs[72]
1542* (Given, auxiliary) DATE-OBS keyvalue, being the date at the start of the
1543* observation unless otherwise explained in the DATE-OBS keycomment, in
1544* ISO format, yyyy-mm-ddThh:mm:ss.
1545*
1546* It is not necessary to reset the wcsprm struct (via wcsset()) when
1547* wcsprm::dateobs is changed.
1548*
1549* char datebeg[72]
1550* (Given, auxiliary) DATE-BEG keyvalue, being the date at the start of the
1551* observation in ISO format, yyyy-mm-ddThh:mm:ss.
1552*
1553* It is not necessary to reset the wcsprm struct (via wcsset()) when
1554* wcsprm::datebeg is changed.
1555*
1556* char dateavg[72]
1557* (Given, auxiliary) DATE-AVG keyvalue, being the date at a representative
1558* mid-point of the observation in ISO format, yyyy-mm-ddThh:mm:ss.
1559*
1560* It is not necessary to reset the wcsprm struct (via wcsset()) when
1561* wcsprm::dateavg is changed.
1562*
1563* char dateend[72]
1564* (Given, auxiliary) DATE-END keyvalue, baing the date at the end of the
1565* observation in ISO format, yyyy-mm-ddThh:mm:ss.
1566*
1567* It is not necessary to reset the wcsprm struct (via wcsset()) when
1568* wcsprm::dateend is changed.
1569*
1570* double mjdobs
1571* (Given, auxiliary) MJD-OBS keyvalue, equivalent to DATE-OBS expressed
1572* as a Modified Julian Date (MJD = JD - 2400000.5).
1573*
1574* It is not necessary to reset the wcsprm struct (via wcsset()) when
1575* wcsprm::mjdobs is changed.
1576*
1577* double mjdbeg
1578* (Given, auxiliary) MJD-BEG keyvalue, equivalent to DATE-BEG expressed
1579* as a Modified Julian Date (MJD = JD - 2400000.5).
1580*
1581* It is not necessary to reset the wcsprm struct (via wcsset()) when
1582* wcsprm::mjdbeg is changed.
1583*
1584* double mjdavg
1585* (Given, auxiliary) MJD-AVG keyvalue, equivalent to DATE-AVG expressed
1586* as a Modified Julian Date (MJD = JD - 2400000.5).
1587*
1588* It is not necessary to reset the wcsprm struct (via wcsset()) when
1589* wcsprm::mjdavg is changed.
1590*
1591* double mjdend
1592* (Given, auxiliary) MJD-END keyvalue, equivalent to DATE-END expressed
1593* as a Modified Julian Date (MJD = JD - 2400000.5).
1594*
1595* It is not necessary to reset the wcsprm struct (via wcsset()) when
1596* wcsprm::mjdend is changed.
1597*
1598* double jepoch
1599* (Given, auxiliary) JEPOCH keyvalue, equivalent to DATE-OBS expressed
1600* as a Julian epoch.
1601*
1602* It is not necessary to reset the wcsprm struct (via wcsset()) when
1603* wcsprm::jepoch is changed.
1604*
1605* double bepoch
1606* (Given, auxiliary) BEPOCH keyvalue, equivalent to DATE-OBS expressed
1607* as a Besselian epoch
1608*
1609* It is not necessary to reset the wcsprm struct (via wcsset()) when
1610* wcsprm::bepoch is changed.
1611*
1612* double tstart
1613* (Given, auxiliary) TSTART keyvalue, equivalent to DATE-BEG expressed
1614* as a time in units of TIMEUNIT relative to DATEREF+TIMEOFFS.
1615*
1616* It is not necessary to reset the wcsprm struct (via wcsset()) when
1617* wcsprm::tstart is changed.
1618*
1619* double tstop
1620* (Given, auxiliary) TSTOP keyvalue, equivalent to DATE-END expressed
1621* as a time in units of TIMEUNIT relative to DATEREF+TIMEOFFS.
1622*
1623* It is not necessary to reset the wcsprm struct (via wcsset()) when
1624* wcsprm::tstop is changed.
1625*
1626* double xposure
1627* (Given, auxiliary) XPOSURE keyvalue, being the effective exposure time
1628* in units of TIMEUNIT.
1629*
1630* It is not necessary to reset the wcsprm struct (via wcsset()) when
1631* wcsprm::xposure is changed.
1632*
1633* double telapse
1634* (Given, auxiliary) TELAPSE keyvalue, equivalent to the elapsed time
1635* between DATE-BEG and DATE-END, in units of TIMEUNIT.
1636*
1637* It is not necessary to reset the wcsprm struct (via wcsset()) when
1638* wcsprm::telapse is changed.
1639*
1640* double timsyer
1641* (Given, auxiliary) TIMSYER keyvalue, being the absolute error of the
1642* time values, in units of TIMEUNIT.
1643*
1644* It is not necessary to reset the wcsprm struct (via wcsset()) when
1645* wcsprm::timsyer is changed.
1646*
1647* double timrder
1648* (Given, auxiliary) TIMRDER keyvalue, being the accuracy of time stamps
1649* relative to each other, in units of TIMEUNIT.
1650*
1651* It is not necessary to reset the wcsprm struct (via wcsset()) when
1652* wcsprm::timrder is changed.
1653*
1654* double timedel
1655* (Given, auxiliary) TIMEDEL keyvalue, being the resolution of the time
1656* stamps.
1657*
1658* It is not necessary to reset the wcsprm struct (via wcsset()) when
1659* wcsprm::timedel is changed.
1660*
1661* double timepixr
1662* (Given, auxiliary) TIMEPIXR keyvalue, being the relative position of the
1663* time stamps in binned time intervals, a value between 0.0 and 1.0.
1664*
1665* It is not necessary to reset the wcsprm struct (via wcsset()) when
1666* wcsprm::timepixr is changed.
1667*
1668* double obsgeo[6]
1669* (Given, auxiliary) Location of the observer in a standard terrestrial
1670* reference frame. The first three give ITRS Cartesian coordinates
1671* OBSGEO-X [m], OBSGEO-Y [m], OBSGEO-Z [m], and the second three give
1672* OBSGEO-L [deg], OBSGEO-B [deg], OBSGEO-H [m], which are related through
1673* a standard transformation.
1674*
1675* It is not necessary to reset the wcsprm struct (via wcsset()) when
1676* wcsprm::obsgeo is changed.
1677*
1678* char obsorbit[72]
1679* (Given, auxiliary) OBSORBIT keyvalue, being the URI, URL, or name of an
1680* orbit ephemeris file giving spacecraft coordinates relating to TREFPOS.
1681*
1682* It is not necessary to reset the wcsprm struct (via wcsset()) when
1683* wcsprm::obsorbit is changed.
1684*
1685* char radesys[72]
1686* (Given, auxiliary) The equatorial or ecliptic coordinate system type,
1687* RADESYSa.
1688*
1689* It is not necessary to reset the wcsprm struct (via wcsset()) when
1690* wcsprm::radesys is changed.
1691*
1692* double equinox
1693* (Given, auxiliary) The equinox associated with dynamical equatorial or
1694* ecliptic coordinate systems, EQUINOXa (or EPOCH in older headers). Not
1695* applicable to ICRS equatorial or ecliptic coordinates.
1696*
1697* It is not necessary to reset the wcsprm struct (via wcsset()) when
1698* wcsprm::equinox is changed.
1699*
1700* char specsys[72]
1701* (Given, auxiliary) Spectral reference frame (standard of rest),
1702* SPECSYSa.
1703*
1704* It is not necessary to reset the wcsprm struct (via wcsset()) when
1705* wcsprm::specsys is changed.
1706*
1707* char ssysobs[72]
1708* (Given, auxiliary) The spectral reference frame in which there is no
1709* differential variation in the spectral coordinate across the
1710* field-of-view, SSYSOBSa.
1711*
1712* It is not necessary to reset the wcsprm struct (via wcsset()) when
1713* wcsprm::ssysobs is changed.
1714*
1715* double velosys
1716* (Given, auxiliary) The relative radial velocity [m/s] between the
1717* observer and the selected standard of rest in the direction of the
1718* celestial reference coordinate, VELOSYSa.
1719*
1720* It is not necessary to reset the wcsprm struct (via wcsset()) when
1721* wcsprm::velosys is changed.
1722*
1723* double zsource
1724* (Given, auxiliary) The redshift, ZSOURCEa, of the source.
1725*
1726* It is not necessary to reset the wcsprm struct (via wcsset()) when
1727* wcsprm::zsource is changed.
1728*
1729* char ssyssrc[72]
1730* (Given, auxiliary) The spectral reference frame (standard of rest),
1731* SSYSSRCa, in which wcsprm::zsource was measured.
1732*
1733* It is not necessary to reset the wcsprm struct (via wcsset()) when
1734* wcsprm::ssyssrc is changed.
1735*
1736* double velangl
1737* (Given, auxiliary) The angle [deg] that should be used to decompose an
1738* observed velocity into radial and transverse components.
1739*
1740* It is not necessary to reset the wcsprm struct (via wcsset()) when
1741* wcsprm::velangl is changed.
1742*
1743* struct auxprm *aux
1744* (Given, auxiliary) This struct holds auxiliary coordinate system
1745* information of a specialist nature. While these parameters may be
1746* widely recognized within particular fields of astronomy, they differ
1747* from the above auxiliary parameters in not being defined by any of the
1748* FITS WCS standards. Collecting them together in a separate struct that
1749* is allocated only when required helps to control bloat in the size of
1750* the wcsprm struct.
1751*
1752* int ntab
1753* (Given) See wcsprm::tab.
1754*
1755* int nwtb
1756* (Given) See wcsprm::wtb.
1757*
1758* struct tabprm *tab
1759* (Given) Address of the first element of an array of ntab tabprm structs
1760* for which memory has been allocated. These are used to store tabular
1761* transformation parameters.
1762*
1763* Although technically wcsprm::ntab and tab are "given", they will
1764* normally be set by invoking wcstab(), whether directly or indirectly.
1765*
1766* The tabprm structs contain some members that must be supplied and others
1767* that are derived. The information to be supplied comes primarily from
1768* arrays stored in one or more FITS binary table extensions. These
1769* arrays, referred to here as "wcstab arrays", are themselves located by
1770* parameters stored in the FITS image header.
1771*
1772* struct wtbarr *wtb
1773* (Given) Address of the first element of an array of nwtb wtbarr structs
1774* for which memory has been allocated. These are used in extracting
1775* wcstab arrays from a FITS binary table.
1776*
1777* Although technically wcsprm::nwtb and wtb are "given", they will
1778* normally be set by invoking wcstab(), whether directly or indirectly.
1779*
1780* char lngtyp[8]
1781* (Returned) Four-character WCS celestial longitude and ...
1782* char lattyp[8]
1783* (Returned) ... latitude axis types. e.g. "RA", "DEC", "GLON", "GLAT",
1784* etc. extracted from 'RA--', 'DEC-', 'GLON', 'GLAT', etc. in the first
1785* four characters of CTYPEia but with trailing dashes removed. (Declared
1786* as char[8] for alignment reasons.)
1787*
1788* int lng
1789* (Returned) Index for the longitude coordinate, and ...
1790* int lat
1791* (Returned) ... index for the latitude coordinate, and ...
1792* int spec
1793* (Returned) ... index for the spectral coordinate, and ...
1794* int time
1795* (Returned) ... index for the time coordinate in the imgcrd[][] and
1796* world[][] arrays in the API of wcsp2s(), wcss2p() and wcsmix().
1797*
1798* These may also serve as indices into the pixcrd[][] array provided that
1799* the PCi_ja matrix does not transpose axes.
1800*
1801* int cubeface
1802* (Returned) Index into the pixcrd[][] array for the CUBEFACE axis. This
1803* is used for quadcube projections where the cube faces are stored on a
1804* separate axis (see wcs.h).
1805*
1806* int *types
1807* (Returned) Address of the first element of an array of int containing a
1808* four-digit type code for each axis.
1809*
1810* - First digit (i.e. 1000s):
1811* - 0: Non-specific coordinate type.
1812* - 1: Stokes coordinate.
1813* - 2: Celestial coordinate (including CUBEFACE).
1814* - 3: Spectral coordinate.
1815* - 4: Time coordinate.
1816*
1817* - Second digit (i.e. 100s):
1818* - 0: Linear axis.
1819* - 1: Quantized axis (STOKES, CUBEFACE).
1820* - 2: Non-linear celestial axis.
1821* - 3: Non-linear spectral axis.
1822* - 4: Logarithmic axis.
1823* - 5: Tabular axis.
1824*
1825* - Third digit (i.e. 10s):
1826* - 0: Group number, e.g. lookup table number, being an index into the
1827* tabprm array (see above).
1828*
1829* - The fourth digit is used as a qualifier depending on the axis type.
1830*
1831* - For celestial axes:
1832* - 0: Longitude coordinate.
1833* - 1: Latitude coordinate.
1834* - 2: CUBEFACE number.
1835*
1836* - For lookup tables: the axis number in a multidimensional table.
1837*
1838* CTYPEia in "4-3" form with unrecognized algorithm code will have its
1839* type set to -1 and generate an error.
1840*
1841* struct linprm lin
1842* (Returned) Linear transformation parameters (usage is described in the
1843* prologue to lin.h).
1844*
1845* struct celprm cel
1846* (Returned) Celestial transformation parameters (usage is described in
1847* the prologue to cel.h).
1848*
1849* struct spcprm spc
1850* (Returned) Spectral transformation parameters (usage is described in the
1851* prologue to spc.h).
1852*
1853* struct wcserr *err
1854* (Returned) If enabled, when an error status is returned, this struct
1855* contains detailed information about the error, see wcserr_enable().
1856*
1857* int m_flag
1858* (For internal use only.)
1859* int m_naxis
1860* (For internal use only.)
1861* double *m_crpix
1862* (For internal use only.)
1863* double *m_pc
1864* (For internal use only.)
1865* double *m_cdelt
1866* (For internal use only.)
1867* double *m_crval
1868* (For internal use only.)
1869* char (*m_cunit)[72]
1870* (For internal use only.)
1871* char (*m_ctype)[72]
1872* (For internal use only.)
1873* struct pvcard *m_pv
1874* (For internal use only.)
1875* struct pscard *m_ps
1876* (For internal use only.)
1877* double *m_cd
1878* (For internal use only.)
1879* double *m_crota
1880* (For internal use only.)
1881* int *m_colax
1882* (For internal use only.)
1883* char (*m_cname)[72]
1884* (For internal use only.)
1885* double *m_crder
1886* (For internal use only.)
1887* double *m_csyer
1888* (For internal use only.)
1889* double *m_czphs
1890* (For internal use only.)
1891* double *m_cperi
1892* (For internal use only.)
1893* struct tabprm *m_tab
1894* (For internal use only.)
1895* struct wtbarr *m_wtb
1896* (For internal use only.)
1897*
1898*
1899* pvcard struct - Store for PVi_ma keyrecords
1900* -------------------------------------------
1901* The pvcard struct is used to pass the parsed contents of PVi_ma keyrecords
1902* to wcsset() via the wcsprm struct.
1903*
1904* All members of this struct are to be set by the user.
1905*
1906* int i
1907* (Given) Axis number (1-relative), as in the FITS PVi_ma keyword. If
1908* i == 0, wcsset() will replace it with the latitude axis number.
1909*
1910* int m
1911* (Given) Parameter number (non-negative), as in the FITS PVi_ma keyword.
1912*
1913* double value
1914* (Given) Parameter value.
1915*
1916*
1917* pscard struct - Store for PSi_ma keyrecords
1918* -------------------------------------------
1919* The pscard struct is used to pass the parsed contents of PSi_ma keyrecords
1920* to wcsset() via the wcsprm struct.
1921*
1922* All members of this struct are to be set by the user.
1923*
1924* int i
1925* (Given) Axis number (1-relative), as in the FITS PSi_ma keyword.
1926*
1927* int m
1928* (Given) Parameter number (non-negative), as in the FITS PSi_ma keyword.
1929*
1930* char value[72]
1931* (Given) Parameter value.
1932*
1933*
1934* auxprm struct - Additional auxiliary parameters
1935* -----------------------------------------------
1936* The auxprm struct holds auxiliary coordinate system information of a
1937* specialist nature. It is anticipated that this struct will expand in future
1938* to accomodate additional parameters.
1939*
1940* All members of this struct are to be set by the user.
1941*
1942* double rsun_ref
1943* (Given, auxiliary) Reference radius of the Sun used in coordinate
1944* calculations (m).
1945*
1946* double dsun_obs
1947* (Given, auxiliary) Distance between the centre of the Sun and the
1948* observer (m).
1949*
1950* double crln_obs
1951* (Given, auxiliary) Carrington heliographic longitude of the observer
1952* (deg).
1953*
1954* double hgln_obs
1955* (Given, auxiliary) Stonyhurst heliographic longitude of the observer
1956* (deg).
1957*
1958* double hglt_obs
1959* (Given, auxiliary) Heliographic latitude (Carrington or Stonyhurst) of
1960* the observer (deg).
1961*
1962* double a_radius
1963* Length of the semi-major axis of a triaxial ellipsoid approximating the
1964* shape of a body (e.g. planet) in the solar system (m).
1965*
1966* double b_radius
1967* Length of the intermediate axis, normal to the semi-major and semi-minor
1968* axes, of a triaxial ellipsoid approximating the shape of a body (m).
1969*
1970* double c_radius
1971* Length of the semi-minor axis, normal to the semi-major axis, of a
1972* triaxial ellipsoid approximating the shape of a body (m).
1973*
1974* double blon_obs
1975* Bodycentric longitude of the observer in the coordinate system fixed to
1976* the planet or other solar system body (deg, in range 0 to 360).
1977*
1978* double blat_obs
1979* Bodycentric latitude of the observer in the coordinate system fixed to
1980* the planet or other solar system body (deg).
1981*
1982* double bdis_obs
1983* Bodycentric distance of the observer (m).
1984*
1985* Global variable: const char *wcs_errmsg[] - Status return messages
1986* ------------------------------------------------------------------
1987* Error messages to match the status value returned from each function.
1988*
1989*===========================================================================*/
1990
1991#ifndef WCSLIB_WCS
1992#define WCSLIB_WCS
1993
1994#include "lin.h"
1995#include "cel.h"
1996#include "spc.h"
1997
1998#ifdef __cplusplus
1999extern "C" {
2000#define wtbarr wtbarr_s // See prologue of wtbarr.h.
2001#endif
2002
2003#define WCSSUB_LONGITUDE 0x1001
2004#define WCSSUB_LATITUDE 0x1002
2005#define WCSSUB_CUBEFACE 0x1004
2006#define WCSSUB_CELESTIAL 0x1007
2007#define WCSSUB_SPECTRAL 0x1008
2008#define WCSSUB_STOKES 0x1010
2009#define WCSSUB_TIME 0x1020
2010
2011
2012#define WCSCOMPARE_ANCILLARY 0x0001
2013#define WCSCOMPARE_TILING 0x0002
2014#define WCSCOMPARE_CRPIX 0x0004
2015
2016
2017extern const char *wcs_errmsg[];
2018
2019enum wcs_errmsg_enum {
2020 WCSERR_SUCCESS = 0, // Success.
2021 WCSERR_NULL_POINTER = 1, // Null wcsprm pointer passed.
2022 WCSERR_MEMORY = 2, // Memory allocation failed.
2023 WCSERR_SINGULAR_MTX = 3, // Linear transformation matrix is singular.
2024 WCSERR_BAD_CTYPE = 4, // Inconsistent or unrecognized coordinate
2025 // axis type.
2026 WCSERR_BAD_PARAM = 5, // Invalid parameter value.
2027 WCSERR_BAD_COORD_TRANS = 6, // Unrecognized coordinate transformation
2028 // parameter.
2029 WCSERR_ILL_COORD_TRANS = 7, // Ill-conditioned coordinate transformation
2030 // parameter.
2031 WCSERR_BAD_PIX = 8, // One or more of the pixel coordinates were
2032 // invalid.
2033 WCSERR_BAD_WORLD = 9, // One or more of the world coordinates were
2034 // invalid.
2035 WCSERR_BAD_WORLD_COORD = 10, // Invalid world coordinate.
2036 WCSERR_NO_SOLUTION = 11, // No solution found in the specified
2037 // interval.
2038 WCSERR_BAD_SUBIMAGE = 12, // Invalid subimage specification.
2039 WCSERR_NON_SEPARABLE = 13, // Non-separable subimage coordinate system.
2040 WCSERR_UNSET = 14 // wcsprm struct is unset.
2041};
2042
2043
2044// Struct used for storing PVi_ma keywords.
2045struct pvcard {
2046 int i; // Axis number, as in PVi_ma (1-relative).
2047 int m; // Parameter number, ditto (0-relative).
2048 double value; // Parameter value.
2049};
2050
2051// Size of the pvcard struct in int units, used by the Fortran wrappers.
2052#define PVLEN (sizeof(struct pvcard)/sizeof(int))
2053
2054// Struct used for storing PSi_ma keywords.
2055struct pscard {
2056 int i; // Axis number, as in PSi_ma (1-relative).
2057 int m; // Parameter number, ditto (0-relative).
2058 char value[72]; // Parameter value.
2059};
2060
2061// Size of the pscard struct in int units, used by the Fortran wrappers.
2062#define PSLEN (sizeof(struct pscard)/sizeof(int))
2063
2064// Struct used to hold additional auxiliary parameters.
2065struct auxprm {
2066 double rsun_ref; // Solar radius.
2067 double dsun_obs; // Distance from Sun centre to observer.
2068 double crln_obs; // Carrington heliographic lng of observer.
2069 double hgln_obs; // Stonyhurst heliographic lng of observer.
2070 double hglt_obs; // Heliographic latitude of observer.
2071 double a_radius; // Semi-major axis of solar system body.
2072 double b_radius; // Semi-intermediate axis of solar system body.
2073 double c_radius; // Semi-minor axis of solar system body.
2074 double blon_obs; // Bodycentric longitude of observer.
2075 double blat_obs; // Bodycentric latitude of observer.
2076 double bdis_obs; // Bodycentric distance of observer.
2077 double dummy[2]; // Reserved for future use.
2078};
2079
2080// Size of the auxprm struct in int units, used by the Fortran wrappers.
2081#define AUXLEN (sizeof(struct auxprm)/sizeof(int))
2082
2083
2084struct wcsprm {
2085 // Initialization flag (see the prologue above).
2086 //--------------------------------------------------------------------------
2087 int flag; // Set to zero to force initialization.
2088
2089 // FITS header keyvalues to be provided (see the prologue above).
2090 //--------------------------------------------------------------------------
2091 int naxis; // Number of axes (pixel and coordinate).
2092 double *crpix; // CRPIXja keyvalues for each pixel axis.
2093 double *pc; // PCi_ja linear transformation matrix.
2094 double *cdelt; // CDELTia keyvalues for each coord axis.
2095 double *crval; // CRVALia keyvalues for each coord axis.
2096
2097 char (*cunit)[72]; // CUNITia keyvalues for each coord axis.
2098 char (*ctype)[72]; // CTYPEia keyvalues for each coord axis.
2099
2100 double lonpole; // LONPOLEa keyvalue.
2101 double latpole; // LATPOLEa keyvalue.
2102
2103 double restfrq; // RESTFRQa keyvalue.
2104 double restwav; // RESTWAVa keyvalue.
2105
2106 int npv; // Number of PVi_ma keywords, and the
2107 int npvmax; // number for which space was allocated.
2108 struct pvcard *pv; // PVi_ma keywords for each i and m.
2109
2110 int nps; // Number of PSi_ma keywords, and the
2111 int npsmax; // number for which space was allocated.
2112 struct pscard *ps; // PSi_ma keywords for each i and m.
2113
2114 // Alternative header keyvalues (see the prologue above).
2115 //--------------------------------------------------------------------------
2116 double *cd; // CDi_ja linear transformation matrix.
2117 double *crota; // CROTAi keyvalues for each coord axis.
2118 int altlin; // Alternative representations
2119 // Bit 0: PCi_ja is present,
2120 // Bit 1: CDi_ja is present,
2121 // Bit 2: CROTAi is present.
2122 int velref; // AIPS velocity code, VELREF.
2123
2124 // Auxiliary coordinate system information of a general nature. Not
2125 // used by WCSLIB. Refer to the prologue comments above for a brief
2126 // explanation of these values.
2127 char alt[4];
2128 int colnum;
2129 int *colax;
2130 // Auxiliary coordinate axis information.
2131 char (*cname)[72];
2132 double *crder;
2133 double *csyer;
2134 double *czphs;
2135 double *cperi;
2136
2137 char wcsname[72];
2138 // Time reference system and measurement.
2139 char timesys[72], trefpos[72], trefdir[72], plephem[72];
2140 char timeunit[72];
2141 char dateref[72];
2142 double mjdref[2];
2143 double timeoffs;
2144 // Data timestamps and durations.
2145 char dateobs[72], datebeg[72], dateavg[72], dateend[72];
2146 double mjdobs, mjdbeg, mjdavg, mjdend;
2147 double jepoch, bepoch;
2148 double tstart, tstop;
2149 double xposure, telapse;
2150 // Timing accuracy.
2151 double timsyer, timrder;
2152 double timedel, timepixr;
2153 // Spatial & celestial reference frame.
2154 double obsgeo[6];
2155 char obsorbit[72];
2156 char radesys[72];
2157 double equinox;
2158 char specsys[72];
2159 char ssysobs[72];
2160 double velosys;
2161 double zsource;
2162 char ssyssrc[72];
2163 double velangl;
2164
2165 // Additional auxiliary coordinate system information of a specialist
2166 // nature. Not used by WCSLIB. Refer to the prologue comments above.
2167 struct auxprm *aux;
2168
2169 // Coordinate lookup tables (see the prologue above).
2170 //--------------------------------------------------------------------------
2171 int ntab; // Number of separate tables.
2172 int nwtb; // Number of wtbarr structs.
2173 struct tabprm *tab; // Tabular transformation parameters.
2174 struct wtbarr *wtb; // Array of wtbarr structs.
2175
2176 //--------------------------------------------------------------------------
2177 // Information derived from the FITS header keyvalues by wcsset().
2178 //--------------------------------------------------------------------------
2179 char lngtyp[8], lattyp[8]; // Celestial axis types, e.g. RA, DEC.
2180 int lng, lat, spec, time; // Longitude, latitude, spectral, and time
2181 // axis indices (0-relative).
2182 int cubeface; // True if there is a CUBEFACE axis.
2183 int dummy; // Dummy for alignment purposes.
2184 int *types; // Coordinate type codes for each axis.
2185
2186 struct linprm lin; // Linear transformation parameters.
2187 struct celprm cel; // Celestial transformation parameters.
2188 struct spcprm spc; // Spectral transformation parameters.
2189
2190 //--------------------------------------------------------------------------
2191 // THE REMAINDER OF THE WCSPRM STRUCT IS PRIVATE.
2192 //--------------------------------------------------------------------------
2193
2194 // Error handling, if enabled.
2195 //--------------------------------------------------------------------------
2196 struct wcserr *err;
2197
2198 // Memory management.
2199 //--------------------------------------------------------------------------
2200 int m_flag, m_naxis;
2201 double *m_crpix, *m_pc, *m_cdelt, *m_crval;
2202 char (*m_cunit)[72], (*m_ctype)[72];
2203 struct pvcard *m_pv;
2204 struct pscard *m_ps;
2205 double *m_cd, *m_crota;
2206 int *m_colax;
2207 char (*m_cname)[72];
2208 double *m_crder, *m_csyer, *m_czphs, *m_cperi;
2209 struct auxprm *m_aux;
2210 struct tabprm *m_tab;
2211 struct wtbarr *m_wtb;
2212};
2213
2214// Size of the wcsprm struct in int units, used by the Fortran wrappers.
2215#define WCSLEN (sizeof(struct wcsprm)/sizeof(int))
2216
2217
2218int wcsnpv(int n);
2219
2220int wcsnps(int n);
2221
2222int wcsini(int alloc, int naxis, struct wcsprm *wcs);
2223
2224int wcsinit(int alloc, int naxis, struct wcsprm *wcs, int npvmax, int npsmax,
2225 int ndpmax);
2226
2227int wcsauxi(int alloc, struct wcsprm *wcs);
2228
2229int wcssub(int alloc, const struct wcsprm *wcssrc, int *nsub, int axes[],
2230 struct wcsprm *wcsdst);
2231
2232int wcscompare(int cmp, double tol, const struct wcsprm *wcs1,
2233 const struct wcsprm *wcs2, int *equal);
2234
2235int wcsfree(struct wcsprm *wcs);
2236
2237int wcstrim(struct wcsprm *wcs);
2238
2239int wcssize(const struct wcsprm *wcs, int sizes[2]);
2240
2241int auxsize(const struct auxprm *aux, int sizes[2]);
2242
2243int wcsprt(const struct wcsprm *wcs);
2244
2245int wcsperr(const struct wcsprm *wcs, const char *prefix);
2246
2247int wcsbchk(struct wcsprm *wcs, int bounds);
2248
2249int wcsset(struct wcsprm *wcs);
2250
2251int wcsp2s(struct wcsprm *wcs, int ncoord, int nelem, const double pixcrd[],
2252 double imgcrd[], double phi[], double theta[], double world[],
2253 int stat[]);
2254
2255int wcss2p(struct wcsprm *wcs, int ncoord, int nelem, const double world[],
2256 double phi[], double theta[], double imgcrd[], double pixcrd[],
2257 int stat[]);
2258
2259int wcsmix(struct wcsprm *wcs, int mixpix, int mixcel, const double vspan[2],
2260 double vstep, int viter, double world[], double phi[],
2261 double theta[], double imgcrd[], double pixcrd[]);
2262
2263int wcsccs(struct wcsprm *wcs, double lng2p1, double lat2p1, double lng1p2,
2264 const char *clng, const char *clat, const char *radesys,
2265 double equinox, const char *alt);
2266
2267int wcssptr(struct wcsprm *wcs, int *i, char ctype[9]);
2268
2269const char* wcslib_version(int vers[3]);
2270
2271// Defined mainly for backwards compatibility, use wcssub() instead.
2272#define wcscopy(alloc, wcssrc, wcsdst) wcssub(alloc, wcssrc, 0x0, 0x0, wcsdst)
2273
2274
2275// Deprecated.
2276#define wcsini_errmsg wcs_errmsg
2277#define wcssub_errmsg wcs_errmsg
2278#define wcscopy_errmsg wcs_errmsg
2279#define wcsfree_errmsg wcs_errmsg
2280#define wcsprt_errmsg wcs_errmsg
2281#define wcsset_errmsg wcs_errmsg
2282#define wcsp2s_errmsg wcs_errmsg
2283#define wcss2p_errmsg wcs_errmsg
2284#define wcsmix_errmsg wcs_errmsg
2285
2286#ifdef __cplusplus
2287#undef wtbarr
2288}
2289#endif
2290
2291#endif // WCSLIB_WCS
auxprm
Additional auxiliary parameters.
Definition wcs.h:2065
auxprm::dsun_obs
double dsun_obs
Definition wcs.h:2067
auxprm::hglt_obs
double hglt_obs
Definition wcs.h:2070
auxprm::c_radius
double c_radius
Definition wcs.h:2073
auxprm::hgln_obs
double hgln_obs
Definition wcs.h:2069
auxprm::dummy
double dummy[2]
Definition wcs.h:2077
auxprm::crln_obs
double crln_obs
Definition wcs.h:2068
auxprm::b_radius
double b_radius
Definition wcs.h:2072
auxprm::blon_obs
double blon_obs
Definition wcs.h:2074
auxprm::a_radius
double a_radius
Definition wcs.h:2071
auxprm::rsun_ref
double rsun_ref
Definition wcs.h:2066
auxprm::bdis_obs
double bdis_obs
Definition wcs.h:2076
auxprm::blat_obs
double blat_obs
Definition wcs.h:2075
celprm
Celestial transformation parameters.
Definition cel.h:423
linprm
Linear transformation parameters.
Definition lin.h:680
pscard
Store for PSi_ma keyrecords.
Definition wcs.h:2055
pscard::i
int i
Definition wcs.h:2056
pscard::m
int m
Definition wcs.h:2057
pscard::value
char value[72]
Definition wcs.h:2058
pvcard
Store for PVi_ma keyrecords.
Definition wcs.h:2045
pvcard::value
double value
Definition wcs.h:2048
pvcard::i
int i
Definition wcs.h:2046
pvcard::m
int m
Definition wcs.h:2047
spcprm
Spectral transformation parameters.
Definition spc.h:832
tabprm
Tabular transformation parameters.
Definition tab.h:573
wcserr
Error message handling.
Definition wcserr.h:243
wcsprm
Coordinate transformation parameters.
Definition wcs.h:2084
wcsprm::timeunit
char timeunit[72]
Definition wcs.h:2140
wcsprm::m_ps
struct pscard * m_ps
Definition wcs.h:2204
wcsprm::timesys
char timesys[72]
Definition wcs.h:2139
wcsprm::pv
struct pvcard * pv
Definition wcs.h:2108
wcsprm::dateref
char dateref[72]
Definition wcs.h:2141
wcsprm::mjdavg
double mjdavg
Definition wcs.h:2146
wcsprm::lng
int lng
Definition wcs.h:2180
wcsprm::czphs
double * czphs
Definition wcs.h:2134
wcsprm::m_cname
char(* m_cname)[72]
Definition wcs.h:2207
wcsprm::zsource
double zsource
Definition wcs.h:2161
wcsprm::m_crder
double * m_crder
Definition wcs.h:2208
wcsprm::npv
int npv
Definition wcs.h:2106
wcsprm::timrder
double timrder
Definition wcs.h:2151
wcsprm::trefpos
char trefpos[72]
Definition wcs.h:2139
wcsprm::telapse
double telapse
Definition wcs.h:2149
wcsprm::m_csyer
double * m_csyer
Definition wcs.h:2208
wcsprm::tstart
double tstart
Definition wcs.h:2148
wcsprm::csyer
double * csyer
Definition wcs.h:2133
wcsprm::m_crpix
double * m_crpix
Definition wcs.h:2201
wcsprm::cperi
double * cperi
Definition wcs.h:2135
wcsprm::mjdend
double mjdend
Definition wcs.h:2146
wcsprm::wcsname
char wcsname[72]
Definition wcs.h:2137
wcsprm::tab
struct tabprm * tab
Definition wcs.h:2173
wcsprm::lin
struct linprm lin
Definition wcs.h:2186
wcsprm::pc
double * pc
Definition wcs.h:2093
wcsprm::flag
int flag
Definition wcs.h:2087
wcsprm::aux
struct auxprm * aux
Definition wcs.h:2167
wcsprm::npsmax
int npsmax
Definition wcs.h:2111
wcsprm::m_cdelt
double * m_cdelt
Definition wcs.h:2201
wcsprm::timeoffs
double timeoffs
Definition wcs.h:2143
wcsprm::crder
double * crder
Definition wcs.h:2132
wcsprm::nps
int nps
Definition wcs.h:2110
wcsprm::m_colax
int * m_colax
Definition wcs.h:2206
wcsprm::m_crval
double * m_crval
Definition wcs.h:2201
wcsprm::timepixr
double timepixr
Definition wcs.h:2152
wcsprm::m_crota
double * m_crota
Definition wcs.h:2205
wcsprm::m_cperi
double * m_cperi
Definition wcs.h:2208
wcsprm::m_flag
int m_flag
Definition wcs.h:2200
wcsprm::lngtyp
char lngtyp[8]
Definition wcs.h:2179
wcsprm::restwav
double restwav
Definition wcs.h:2104
wcsprm::latpole
double latpole
Definition wcs.h:2101
wcsprm::m_naxis
int m_naxis
Definition wcs.h:2200
wcsprm::radesys
char radesys[72]
Definition wcs.h:2156
wcsprm::m_pc
double * m_pc
Definition wcs.h:2201
wcsprm::m_pv
struct pvcard * m_pv
Definition wcs.h:2203
wcsprm::naxis
int naxis
Definition wcs.h:2091
wcsprm::m_czphs
double * m_czphs
Definition wcs.h:2208
wcsprm::colax
int * colax
Definition wcs.h:2129
wcsprm::crval
double * crval
Definition wcs.h:2095
wcsprm::m_cd
double * m_cd
Definition wcs.h:2205
wcsprm::tstop
double tstop
Definition wcs.h:2148
wcsprm::obsgeo
double obsgeo[6]
Definition wcs.h:2154
wcsprm::timsyer
double timsyer
Definition wcs.h:2151
wcsprm::nwtb
int nwtb
Definition wcs.h:2172
wcsprm::ssyssrc
char ssyssrc[72]
Definition wcs.h:2162
wcsprm::equinox
double equinox
Definition wcs.h:2157
wcsprm::altlin
int altlin
Definition wcs.h:2118
wcsprm::wtb
struct wtbarr * wtb
Definition wcs.h:2174
wcsprm::npvmax
int npvmax
Definition wcs.h:2107
wcsprm::cname
char(* cname)[72]
Definition wcs.h:2131
wcsprm::jepoch
double jepoch
Definition wcs.h:2147
wcsprm::ntab
int ntab
Definition wcs.h:2171
wcsprm::ssysobs
char ssysobs[72]
Definition wcs.h:2159
wcsprm::ps
struct pscard * ps
Definition wcs.h:2112
wcsprm::colnum
int colnum
Definition wcs.h:2128
wcsprm::datebeg
char datebeg[72]
Definition wcs.h:2145
wcsprm::velangl
double velangl
Definition wcs.h:2163
wcsprm::mjdbeg
double mjdbeg
Definition wcs.h:2146
wcsprm::cunit
char(* cunit)[72]
Definition wcs.h:2097
wcsprm::bepoch
double bepoch
Definition wcs.h:2147
wcsprm::mjdref
double mjdref[2]
Definition wcs.h:2142
wcsprm::time
int time
Definition wcs.h:2180
wcsprm::trefdir
char trefdir[72]
Definition wcs.h:2139
wcsprm::plephem
char plephem[72]
Definition wcs.h:2139
wcsprm::dateobs
char dateobs[72]
Definition wcs.h:2145
wcsprm::crpix
double * crpix
Definition wcs.h:2092
wcsprm::types
int * types
Definition wcs.h:2184
wcsprm::lat
int lat
Definition wcs.h:2180
wcsprm::spec
int spec
Definition wcs.h:2180
wcsprm::specsys
char specsys[72]
Definition wcs.h:2158
wcsprm::mjdobs
double mjdobs
Definition wcs.h:2146
wcsprm::xposure
double xposure
Definition wcs.h:2149
wcsprm::velref
int velref
Definition wcs.h:2122
wcsprm::cel
struct celprm cel
Definition wcs.h:2187
wcsprm::m_wtb
struct wtbarr * m_wtb
Definition wcs.h:2211
wcsprm::dateend
char dateend[72]
Definition wcs.h:2145
wcsprm::m_aux
struct auxprm * m_aux
Definition wcs.h:2209
wcsprm::restfrq
double restfrq
Definition wcs.h:2103
wcsprm::cdelt
double * cdelt
Definition wcs.h:2094
wcsprm::cubeface
int cubeface
Definition wcs.h:2182
wcsprm::m_tab
struct tabprm * m_tab
Definition wcs.h:2210
wcsprm::obsorbit
char obsorbit[72]
Definition wcs.h:2155
wcsprm::ctype
char(* ctype)[72]
Definition wcs.h:2098
wcsprm::lattyp
char lattyp[8]
Definition wcs.h:2179
wcsprm::dateavg
char dateavg[72]
Definition wcs.h:2145
wcsprm::alt
char alt[4]
Definition wcs.h:2127
wcsprm::spc
struct spcprm spc
Definition wcs.h:2188
wcsprm::timedel
double timedel
Definition wcs.h:2152
wcsprm::dummy
int dummy
Definition wcs.h:2183
wcsprm::crota
double * crota
Definition wcs.h:2117
wcsprm::m_cunit
char(* m_cunit)[72]
Definition wcs.h:2202
wcsprm::velosys
double velosys
Definition wcs.h:2160
wcsprm::err
struct wcserr * err
Definition wcs.h:2196
wcsprm::lonpole
double lonpole
Definition wcs.h:2100
wcsprm::cd
double * cd
Definition wcs.h:2116
wtbarr
Extraction of coordinate lookup tables from BINTABLE.
Definition getwcstab.h:167
wtbarr::i
int i
Definition getwcstab.h:168
wcs_errmsg_enum
wcs_errmsg_enum
Definition wcs.h:2019
WCSERR_BAD_WORLD
@ WCSERR_BAD_WORLD
Definition wcs.h:2033
WCSERR_BAD_PIX
@ WCSERR_BAD_PIX
Definition wcs.h:2031
WCSERR_SINGULAR_MTX
@ WCSERR_SINGULAR_MTX
Definition wcs.h:2023
WCSERR_NON_SEPARABLE
@ WCSERR_NON_SEPARABLE
Definition wcs.h:2039
WCSERR_BAD_CTYPE
@ WCSERR_BAD_CTYPE
Definition wcs.h:2024
WCSERR_MEMORY
@ WCSERR_MEMORY
Definition wcs.h:2022
WCSERR_BAD_WORLD_COORD
@ WCSERR_BAD_WORLD_COORD
Definition wcs.h:2035
WCSERR_BAD_COORD_TRANS
@ WCSERR_BAD_COORD_TRANS
Definition wcs.h:2027
WCSERR_NO_SOLUTION
@ WCSERR_NO_SOLUTION
Definition wcs.h:2036
WCSERR_BAD_SUBIMAGE
@ WCSERR_BAD_SUBIMAGE
Definition wcs.h:2038
WCSERR_SUCCESS
@ WCSERR_SUCCESS
Definition wcs.h:2020
WCSERR_UNSET
@ WCSERR_UNSET
Definition wcs.h:2040
WCSERR_NULL_POINTER
@ WCSERR_NULL_POINTER
Definition wcs.h:2021
WCSERR_ILL_COORD_TRANS
@ WCSERR_ILL_COORD_TRANS
Definition wcs.h:2029
WCSERR_BAD_PARAM
@ WCSERR_BAD_PARAM
Definition wcs.h:2026
wcsmix
int wcsmix(struct wcsprm *wcs, int mixpix, int mixcel, const double vspan[2], double vstep, int viter, double world[], double phi[], double theta[], double imgcrd[], double pixcrd[])
Hybrid coordinate transformation.
wcsp2s
int wcsp2s(struct wcsprm *wcs, int ncoord, int nelem, const double pixcrd[], double imgcrd[], double phi[], double theta[], double world[], int stat[])
Pixel-to-world transformation.
wcsini
int wcsini(int alloc, int naxis, struct wcsprm *wcs)
Default constructor for the wcsprm struct.
wcssize
int wcssize(const struct wcsprm *wcs, int sizes[2])
Compute the size of a wcsprm struct.
wcsnpv
int wcsnpv(int n)
Memory allocation for PVi_ma.
wcsfree
int wcsfree(struct wcsprm *wcs)
Destructor for the wcsprm struct.
auxsize
int auxsize(const struct auxprm *aux, int sizes[2])
Compute the size of a auxprm struct.
wcssptr
int wcssptr(struct wcsprm *wcs, int *i, char ctype[9])
Spectral axis translation.
wcss2p
int wcss2p(struct wcsprm *wcs, int ncoord, int nelem, const double world[], double phi[], double theta[], double imgcrd[], double pixcrd[], int stat[])
World-to-pixel transformation.
wcscompare
int wcscompare(int cmp, double tol, const struct wcsprm *wcs1, const struct wcsprm *wcs2, int *equal)
Compare two wcsprm structs for equality.
wcsccs
int wcsccs(struct wcsprm *wcs, double lng2p1, double lat2p1, double lng1p2, const char *clng, const char *clat, const char *radesys, double equinox, const char *alt)
Change celestial coordinate system.
wcs_errmsg
const char * wcs_errmsg[]
wcssub
int wcssub(int alloc, const struct wcsprm *wcssrc, int *nsub, int axes[], struct wcsprm *wcsdst)
Subimage extraction routine for the wcsprm struct.
wcsperr
int wcsperr(const struct wcsprm *wcs, const char *prefix)
Print error messages from a wcsprm struct.
wcsauxi
int wcsauxi(int alloc, struct wcsprm *wcs)
Default constructor for the auxprm struct.
wcsinit
int wcsinit(int alloc, int naxis, struct wcsprm *wcs, int npvmax, int npsmax, int ndpmax)
Default constructor for the wcsprm struct.
wcstrim
int wcstrim(struct wcsprm *wcs)
Free unused arrays in the wcsprm struct.
wcsprt
int wcsprt(const struct wcsprm *wcs)
Print routine for the wcsprm struct.
wcslib_version
const char * wcslib_version(int vers[3])
wcsset
int wcsset(struct wcsprm *wcs)
Setup routine for the wcsprm struct.
wcsnps
int wcsnps(int n)
Memory allocation for PSi_ma.
wcsbchk
int wcsbchk(struct wcsprm *wcs, int bounds)
Enable/disable bounds checking.
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