WCSLIB: wcs.h Source File

WCSLIB 7.6

wcs.h
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1 /*============================================================================
2 WCSLIB 7.6 - an implementation of the FITS WCS standard.
3 Copyright (C) 1995-2021, 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 7.6 2021/04/13 12:57:01 mcalabre Exp $
23 *=============================================================================
24 *
25 * WCSLIB 7.6 - 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 *
331 * Refer to the notes (below) for further usage examples.
332 *
333 * On return, *nsub will be set to the number of axes in
334 * the subimage; this may be zero if there were no axes
335 * of the required type(s) (in which case no memory will
336 * be allocated). axes[] will contain the axis numbers
337 * that were extracted, or 0 for newly created axes. The
338 * vector length must be sufficient to contain all axis
339 * numbers. No checks are performed to verify that the
340 * coordinate axes are consistent, this is done by
341 * wcsset().
342 *
343 * wcsdst struct wcsprm*
344 * Struct describing the subimage. wcsprm::flag should
345 * be set to -1 if wcsdst was not previously initialized
346 * (memory leaks may result if it was previously
347 * initialized).
348 *
349 * Function return value:
350 * int Status return value:
351 * 0: Success.
352 * 1: Null wcsprm pointer passed.
353 * 2: Memory allocation failed.
354 * 12: Invalid subimage specification.
355 * 13: Non-separable subimage coordinate system.
356 *
357 * For returns > 1, a detailed error message is set in
358 * wcsprm::err if enabled, see wcserr_enable().
359 *
360 * Notes:
361 * 1: Combinations of subimage axes of particular types may be extracted in
362 * the same order as they occur in the input image by combining
363 * preprocessor codes, for example
364 *
365 = *nsub = 1;
366 = axes[0] = WCSSUB_LONGITUDE | WCSSUB_LATITUDE | WCSSUB_SPECTRAL;
367 *
368 * would extract the longitude, latitude, and spectral axes in the same
369 * order as the input image. If one of each were present, *nsub = 3 would
370 * be returned.
371 *
372 * For convenience, WCSSUB_CELESTIAL is defined as the combination
373 * WCSSUB_LONGITUDE | WCSSUB_LATITUDE | WCSSUB_CUBEFACE.
374 *
375 * The codes may also be negated to extract all but the types specified,
376 * for example
377 *
378 = *nsub = 4;
379 = axes[0] = WCSSUB_LONGITUDE;
380 = axes[1] = WCSSUB_LATITUDE;
381 = axes[2] = WCSSUB_CUBEFACE;
382 = axes[3] = -(WCSSUB_SPECTRAL | WCSSUB_STOKES);
383 *
384 * The last of these specifies all axis types other than spectral or
385 * Stokes. Extraction is done in the order specified by axes[] a
386 * longitude axis (if present) would be extracted first (via axes[0]) and
387 * not subsequently (via axes[3]). Likewise for the latitude and cubeface
388 * axes in this example.
389 *
390 * From the foregoing, it is apparent that the value of *nsub returned may
391 * be less than or greater than that given. However, it will never exceed
392 * the number of axes in the input image (plus the number of newly-created
393 * axes if any were specified on input).
394 *
395 *
396 * wcscompare() - Compare two wcsprm structs for equality
397 * ------------------------------------------------------
398 * wcscompare() compares two wcsprm structs for equality.
399 *
400 * Given:
401 * cmp int A bit field controlling the strictness of the
402 * comparison. When 0, all fields must be identical.
403 *
404 * The following constants may be or'ed together to
405 * relax the comparison:
406 * WCSCOMPARE_ANCILLARY: Ignore ancillary keywords
407 * that don't change the WCS transformation, such
408 * as DATE-OBS or EQUINOX.
409 * WCSCOMPARE_TILING: Ignore integral differences in
410 * CRPIXja. This is the 'tiling' condition, where
411 * two WCSes cover different regions of the same
412 * map projection and align on the same map grid.
413 * WCSCOMPARE_CRPIX: Ignore any differences at all in
414 * CRPIXja. The two WCSes cover different regions
415 * of the same map projection but may not align on
416 * the same map grid. Overrides WCSCOMPARE_TILING.
417 *
418 * tol double Tolerance for comparison of floating-point values.
419 * For example, for tol == 1e-6, all floating-point
420 * values in the structs must be equal to the first 6
421 * decimal places. A value of 0 implies exact equality.
422 *
423 * wcs1 const struct wcsprm*
424 * The first wcsprm struct to compare.
425 *
426 * wcs2 const struct wcsprm*
427 * The second wcsprm struct to compare.
428 *
429 * Returned:
430 * equal int* Non-zero when the given structs are equal.
431 *
432 * Function return value:
433 * int Status return value:
434 * 0: Success.
435 * 1: Null pointer passed.
436 *
437 *
438 * wcscopy() macro - Copy routine for the wcsprm struct
439 * ----------------------------------------------------
440 * wcscopy() does a deep copy of one wcsprm struct to another. As of
441 * WCSLIB 3.6, it is implemented as a preprocessor macro that invokes
442 * wcssub() with the nsub and axes pointers both set to zero.
443 *
444 *
445 * wcsfree() - Destructor for the wcsprm struct
446 * --------------------------------------------
447 * wcsfree() frees memory allocated for the wcsprm arrays by wcsinit() and/or
448 * wcsset(). wcsinit() records the memory it allocates and wcsfree() will only
449 * attempt to free this.
450 *
451 * PLEASE NOTE: wcsfree() must not be invoked on a wcsprm struct that was not
452 * initialized by wcsinit().
453 *
454 * Given and returned:
455 * wcs struct wcsprm*
456 * Coordinate transformation parameters.
457 *
458 * Function return value:
459 * int Status return value:
460 * 0: Success.
461 * 1: Null wcsprm pointer passed.
462 *
463 *
464 * wcstrim() - Free unused arrays in the wcsprm struct
465 * ---------------------------------------------------
466 * wcstrim() frees memory allocated by wcsinit() for arrays in the wcsprm
467 * struct that remains unused after it has been set up by wcsset().
468 *
469 * The free'd array members are associated with FITS WCS keyrecords that are
470 * rarely used and usually just bloat the struct: wcsprm::crota, wcsprm::colax,
471 * wcsprm::cname, wcsprm::crder, wcsprm::csyer, wcsprm::czphs, and
472 * wcsprm::cperi. If unused, wcsprm::pv, wcsprm::ps, and wcsprm::cd are also
473 * freed.
474 *
475 * Once these arrays have been freed, a test such as
476 =
477 = if (!undefined(wcs->cname[i])) {...}
478 =
479 * must be protected as follows
480 =
481 = if (wcs->cname && !undefined(wcs->cname[i])) {...}
482 =
483 * In addition, if wcsprm::npv is non-zero but less than wcsprm::npvmax, then
484 * the unused space in wcsprm::pv will be recovered (using realloc()).
485 * Likewise for wcsprm::ps.
486 *
487 * Given and returned:
488 * wcs struct wcsprm*
489 * Coordinate transformation parameters.
490 *
491 * Function return value:
492 * int Status return value:
493 * 0: Success.
494 * 1: Null wcsprm pointer passed.
495 * 14: wcsprm struct is unset.
496 *
497 *
498 * wcssize() - Compute the size of a wcsprm struct
499 * -----------------------------------------------
500 * wcssize() computes the full size of a wcsprm struct, including allocated
501 * memory.
502 *
503 * Given:
504 * wcs const struct wcsprm*
505 * Coordinate transformation parameters.
506 *
507 * If NULL, the base size of the struct and the allocated
508 * size are both set to zero.
509 *
510 * Returned:
511 * sizes int[2] The first element is the base size of the struct as
512 * returned by sizeof(struct wcsprm). The second element
513 * is the total allocated size, in bytes, assuming that
514 * the allocation was done by wcsini(). This figure
515 * includes memory allocated for members of constituent
516 * structs, such as wcsprm::lin.
517 *
518 * It is not an error for the struct not to have been set
519 * up via wcsset(), which normally results in additional
520 * memory allocation.
521 *
522 * Function return value:
523 * int Status return value:
524 * 0: Success.
525 *
526 *
527 * auxsize() - Compute the size of a auxprm struct
528 * -----------------------------------------------
529 * auxsize() computes the full size of a auxprm struct, including allocated
530 * memory.
531 *
532 * Given:
533 * aux const struct auxprm*
534 * Auxiliary coordinate information.
535 *
536 * If NULL, the base size of the struct and the allocated
537 * size are both set to zero.
538 *
539 * Returned:
540 * sizes int[2] The first element is the base size of the struct as
541 * returned by sizeof(struct auxprm). The second element
542 * is the total allocated size, in bytes, currently zero.
543 *
544 * Function return value:
545 * int Status return value:
546 * 0: Success.
547 *
548 *
549 * wcsprt() - Print routine for the wcsprm struct
550 * ----------------------------------------------
551 * wcsprt() prints the contents of a wcsprm struct using wcsprintf(). Mainly
552 * intended for diagnostic purposes.
553 *
554 * Given:
555 * wcs const struct wcsprm*
556 * Coordinate transformation parameters.
557 *
558 * Function return value:
559 * int Status return value:
560 * 0: Success.
561 * 1: Null wcsprm pointer passed.
562 *
563 *
564 * wcsperr() - Print error messages from a wcsprm struct
565 * -----------------------------------------------------
566 * wcsperr() prints the error message(s), if any, stored in a wcsprm struct,
567 * and the linprm, celprm, prjprm, spcprm, and tabprm structs that it contains.
568 * If there are no errors then nothing is printed. It uses wcserr_prt(), q.v.
569 *
570 * Given:
571 * wcs const struct wcsprm*
572 * Coordinate transformation parameters.
573 *
574 * prefix const char *
575 * If non-NULL, each output line will be prefixed with
576 * this string.
577 *
578 * Function return value:
579 * int Status return value:
580 * 0: Success.
581 * 1: Null wcsprm pointer passed.
582 *
583 *
584 * wcsbchk() - Enable/disable bounds checking
585 * ------------------------------------------
586 * wcsbchk() is used to control bounds checking in the projection routines.
587 * Note that wcsset() always enables bounds checking. wcsbchk() will invoke
588 * wcsset() on the wcsprm struct beforehand if necessary.
589 *
590 * Given and returned:
591 * wcs struct wcsprm*
592 * Coordinate transformation parameters.
593 *
594 * Given:
595 * bounds int If bounds&1 then enable strict bounds checking for the
596 * spherical-to-Cartesian (s2x) transformation for the
597 * AZP, SZP, TAN, SIN, ZPN, and COP projections.
598 *
599 * If bounds&2 then enable strict bounds checking for the
600 * Cartesian-to-spherical (x2s) transformation for the
601 * HPX and XPH projections.
602 *
603 * If bounds&4 then enable bounds checking on the native
604 * coordinates returned by the Cartesian-to-spherical
605 * (x2s) transformations using prjchk().
606 *
607 * Zero it to disable all checking.
608 *
609 * Function return value:
610 * int Status return value:
611 * 0: Success.
612 * 1: Null wcsprm pointer passed.
613 *
614 *
615 * wcsset() - Setup routine for the wcsprm struct
616 * ----------------------------------------------
617 * wcsset() sets up a wcsprm struct according to information supplied within
618 * it (refer to the description of the wcsprm struct).
619 *
620 * wcsset() recognizes the NCP projection and converts it to the equivalent SIN
621 * projection and likewise translates GLS into SFL. It also translates the
622 * AIPS spectral types ('FREQ-LSR', 'FELO-HEL', etc.), possibly changing the
623 * input header keywords wcsprm::ctype and/or wcsprm::specsys if necessary.
624 *
625 * Note that this routine need not be called directly; it will be invoked by
626 * wcsp2s() and wcss2p() if the wcsprm::flag is anything other than a
627 * predefined magic value.
628 *
629 * Given and returned:
630 * wcs struct wcsprm*
631 * Coordinate transformation parameters.
632 *
633 * Function return value:
634 * int Status return value:
635 * 0: Success.
636 * 1: Null wcsprm pointer passed.
637 * 2: Memory allocation failed.
638 * 3: Linear transformation matrix is singular.
639 * 4: Inconsistent or unrecognized coordinate axis
640 * types.
641 * 5: Invalid parameter value.
642 * 6: Invalid coordinate transformation parameters.
643 * 7: Ill-conditioned coordinate transformation
644 * parameters.
645 *
646 * For returns > 1, a detailed error message is set in
647 * wcsprm::err if enabled, see wcserr_enable().
648 *
649 * Notes:
650 * 1: wcsset() always enables strict bounds checking in the projection
651 * routines (via a call to prjini()). Use wcsbchk() to modify
652 * bounds-checking after wcsset() is invoked.
653 *
654 *
655 * wcsp2s() - Pixel-to-world transformation
656 * ----------------------------------------
657 * wcsp2s() transforms pixel coordinates to world coordinates.
658 *
659 * Given and returned:
660 * wcs struct wcsprm*
661 * Coordinate transformation parameters.
662 *
663 * Given:
664 * ncoord,
665 * nelem int The number of coordinates, each of vector length
666 * nelem but containing wcs.naxis coordinate elements.
667 * Thus nelem must equal or exceed the value of the
668 * NAXIS keyword unless ncoord == 1, in which case nelem
669 * is not used.
670 *
671 * pixcrd const double[ncoord][nelem]
672 * Array of pixel coordinates.
673 *
674 * Returned:
675 * imgcrd double[ncoord][nelem]
676 * Array of intermediate world coordinates. For
677 * celestial axes, imgcrd[][wcs.lng] and
678 * imgcrd[][wcs.lat] are the projected x-, and
679 * y-coordinates in pseudo "degrees". For spectral
680 * axes, imgcrd[][wcs.spec] is the intermediate spectral
681 * coordinate, in SI units.
682 *
683 * phi,theta double[ncoord]
684 * Longitude and latitude in the native coordinate system
685 * of the projection [deg].
686 *
687 * world double[ncoord][nelem]
688 * Array of world coordinates. For celestial axes,
689 * world[][wcs.lng] and world[][wcs.lat] are the
690 * celestial longitude and latitude [deg]. For
691 * spectral axes, imgcrd[][wcs.spec] is the intermediate
692 * spectral coordinate, in SI units.
693 *
694 * stat int[ncoord]
695 * Status return value for each coordinate:
696 * 0: Success.
697 * 1+: A bit mask indicating invalid pixel coordinate
698 * element(s).
699 *
700 * Function return value:
701 * int Status return value:
702 * 0: Success.
703 * 1: Null wcsprm pointer passed.
704 * 2: Memory allocation failed.
705 * 3: Linear transformation matrix is singular.
706 * 4: Inconsistent or unrecognized coordinate axis
707 * types.
708 * 5: Invalid parameter value.
709 * 6: Invalid coordinate transformation parameters.
710 * 7: Ill-conditioned coordinate transformation
711 * parameters.
712 * 8: One or more of the pixel coordinates were
713 * invalid, as indicated by the stat vector.
714 *
715 * For returns > 1, a detailed error message is set in
716 * wcsprm::err if enabled, see wcserr_enable().
717 *
718 *
719 * wcss2p() - World-to-pixel transformation
720 * ----------------------------------------
721 * wcss2p() transforms world coordinates to pixel coordinates.
722 *
723 * Given and returned:
724 * wcs struct wcsprm*
725 * Coordinate transformation parameters.
726 *
727 * Given:
728 * ncoord,
729 * nelem int The number of coordinates, each of vector length nelem
730 * but containing wcs.naxis coordinate elements. Thus
731 * nelem must equal or exceed the value of the NAXIS
732 * keyword unless ncoord == 1, in which case nelem is not
733 * used.
734 *
735 * world const double[ncoord][nelem]
736 * Array of world coordinates. For celestial axes,
737 * world[][wcs.lng] and world[][wcs.lat] are the
738 * celestial longitude and latitude [deg]. For spectral
739 * axes, world[][wcs.spec] is the spectral coordinate, in
740 * SI units.
741 *
742 * Returned:
743 * phi,theta double[ncoord]
744 * Longitude and latitude in the native coordinate
745 * system of the projection [deg].
746 *
747 * imgcrd double[ncoord][nelem]
748 * Array of intermediate world coordinates. For
749 * celestial axes, imgcrd[][wcs.lng] and
750 * imgcrd[][wcs.lat] are the projected x-, and
751 * y-coordinates in pseudo "degrees". For quadcube
752 * projections with a CUBEFACE axis the face number is
753 * also returned in imgcrd[][wcs.cubeface]. For
754 * spectral axes, imgcrd[][wcs.spec] is the intermediate
755 * spectral coordinate, in SI units.
756 *
757 * pixcrd double[ncoord][nelem]
758 * Array of pixel coordinates.
759 *
760 * stat int[ncoord]
761 * Status return value for each coordinate:
762 * 0: Success.
763 * 1+: A bit mask indicating invalid world coordinate
764 * element(s).
765 *
766 * Function return value:
767 * int Status return value:
768 * 0: Success.
769 * 1: Null wcsprm pointer passed.
770 * 2: Memory allocation failed.
771 * 3: Linear transformation matrix is singular.
772 * 4: Inconsistent or unrecognized coordinate axis
773 * types.
774 * 5: Invalid parameter value.
775 * 6: Invalid coordinate transformation parameters.
776 * 7: Ill-conditioned coordinate transformation
777 * parameters.
778 * 9: One or more of the world coordinates were
779 * invalid, as indicated by the stat vector.
780 *
781 * For returns > 1, a detailed error message is set in
782 * wcsprm::err if enabled, see wcserr_enable().
783 *
784 *
785 * wcsmix() - Hybrid coordinate transformation
786 * -------------------------------------------
787 * wcsmix(), given either the celestial longitude or latitude plus an element
788 * of the pixel coordinate, solves for the remaining elements by iterating on
789 * the unknown celestial coordinate element using wcss2p(). Refer also to the
790 * notes below.
791 *
792 * Given and returned:
793 * wcs struct wcsprm*
794 * Indices for the celestial coordinates obtained
795 * by parsing the wcsprm::ctype[].
796 *
797 * Given:
798 * mixpix int Which element of the pixel coordinate is given.
799 *
800 * mixcel int Which element of the celestial coordinate is given:
801 * 1: Celestial longitude is given in
802 * world[wcs.lng], latitude returned in
803 * world[wcs.lat].
804 * 2: Celestial latitude is given in
805 * world[wcs.lat], longitude returned in
806 * world[wcs.lng].
807 *
808 * vspan const double[2]
809 * Solution interval for the celestial coordinate [deg].
810 * The ordering of the two limits is irrelevant.
811 * Longitude ranges may be specified with any convenient
812 * normalization, for example [-120,+120] is the same as
813 * [240,480], except that the solution will be returned
814 * with the same normalization, i.e. lie within the
815 * interval specified.
816 *
817 * vstep const double
818 * Step size for solution search [deg]. If zero, a
819 * sensible, although perhaps non-optimal default will be
820 * used.
821 *
822 * viter int If a solution is not found then the step size will be
823 * halved and the search recommenced. viter controls how
824 * many times the step size is halved. The allowed range
825 * is 5 - 10.
826 *
827 * Given and returned:
828 * world double[naxis]
829 * World coordinate elements. world[wcs.lng] and
830 * world[wcs.lat] are the celestial longitude and
831 * latitude [deg]. Which is given and which returned
832 * depends on the value of mixcel. All other elements
833 * are given.
834 *
835 * Returned:
836 * phi,theta double[naxis]
837 * Longitude and latitude in the native coordinate
838 * system of the projection [deg].
839 *
840 * imgcrd double[naxis]
841 * Image coordinate elements. imgcrd[wcs.lng] and
842 * imgcrd[wcs.lat] are the projected x-, and
843 * y-coordinates in pseudo "degrees".
844 *
845 * Given and returned:
846 * pixcrd double[naxis]
847 * Pixel coordinate. The element indicated by mixpix is
848 * given and the remaining elements are returned.
849 *
850 * Function return value:
851 * int Status return value:
852 * 0: Success.
853 * 1: Null wcsprm pointer passed.
854 * 2: Memory allocation failed.
855 * 3: Linear transformation matrix is singular.
856 * 4: Inconsistent or unrecognized coordinate axis
857 * types.
858 * 5: Invalid parameter value.
859 * 6: Invalid coordinate transformation parameters.
860 * 7: Ill-conditioned coordinate transformation
861 * parameters.
862 * 10: Invalid world coordinate.
863 * 11: No solution found in the specified interval.
864 *
865 * For returns > 1, a detailed error message is set in
866 * wcsprm::err if enabled, see wcserr_enable().
867 *
868 * Notes:
869 * 1: Initially the specified solution interval is checked to see if it's a
870 * "crossing" interval. If it isn't, a search is made for a crossing
871 * solution by iterating on the unknown celestial coordinate starting at
872 * the upper limit of the solution interval and decrementing by the
873 * specified step size. A crossing is indicated if the trial value of the
874 * pixel coordinate steps through the value specified. If a crossing
875 * interval is found then the solution is determined by a modified form of
876 * "regula falsi" division of the crossing interval. If no crossing
877 * interval was found within the specified solution interval then a search
878 * is made for a "non-crossing" solution as may arise from a point of
879 * tangency. The process is complicated by having to make allowance for
880 * the discontinuities that occur in all map projections.
881 *
882 * Once one solution has been determined others may be found by subsequent
883 * invokations of wcsmix() with suitably restricted solution intervals.
884 *
885 * Note the circumstance that arises when the solution point lies at a
886 * native pole of a projection in which the pole is represented as a
887 * finite curve, for example the zenithals and conics. In such cases two
888 * or more valid solutions may exist but wcsmix() only ever returns one.
889 *
890 * Because of its generality wcsmix() is very compute-intensive. For
891 * compute-limited applications more efficient special-case solvers could
892 * be written for simple projections, for example non-oblique cylindrical
893 * projections.
894 *
895 *
896 * wcsccs() - Change celestial coordinate system
897 * ---------------------------------------------
898 * wcsccs() changes the celestial coordinate system of a wcsprm struct. For
899 * example, from equatorial to galactic coordinates.
900 *
901 * Parameters that define the spherical coordinate transformation, essentially
902 * being three Euler angles, must be provided. Thereby wcsccs() does not need
903 * prior knowledge of specific celestial coordinate systems. It also has the
904 * advantage of making it completely general.
905 *
906 * Auxiliary members of the wcsprm struct relating to equatorial celestial
907 * coordinate systems may also be changed.
908 *
909 * Only orthodox spherical coordinate systems are supported. That is, they
910 * must be right-handed, with latitude increasing from zero at the equator to
911 * +90 degrees at the pole. This precludes systems such as aziumuth and zenith
912 * distance, which, however, could be handled as negative azimuth and
913 * elevation.
914 *
915 * PLEASE NOTE: Information in the wcsprm struct relating to the original
916 * coordinate system will be overwritten and therefore lost. If this is
917 * undesirable, invoke wcsccs() on a copy of the struct made with wcssub().
918 * The wcsprm struct is reset on return with an explicit call to wcsset().
919 *
920 * Given and returned:
921 * wcs struct wcsprm*
922 * Coordinate transformation parameters. Particular
923 * "values to be given" elements of the wcsprm struct
924 * are modified.
925 *
926 * Given:
927 * lng2p1,
928 * lat2p1 double Longitude and latitude in the new celestial coordinate
929 * system of the pole (i.e. latitude +90) of the original
930 * system [deg]. See notes 1 and 2 below.
931 *
932 * lng1p2 double Longitude in the original celestial coordinate system
933 * of the pole (i.e. latitude +90) of the new system
934 * [deg]. See note 1 below.
935 *
936 * clng,clat const char*
937 * Longitude and latitude identifiers of the new CTYPEia
938 * celestial axis codes, without trailing dashes. For
939 * example, "RA" and "DEC" or "GLON" and "GLAT". Up to
940 * four characters are used, longer strings need not be
941 * null-terminated.
942 *
943 * radesys const char*
944 * Used when transforming to equatorial coordinates,
945 * identified by clng == "RA" and clat = "DEC". May be
946 * set to the null pointer to preserve the current value.
947 * Up to 71 characters are used, longer strings need not
948 * be null-terminated.
949 *
950 * If the new coordinate system is anything other than
951 * equatorial, then wcsprm::radesys will be cleared.
952 *
953 * equinox double Used when transforming to equatorial coordinates. May
954 * be set to zero to preserve the current value.
955 *
956 * If the new coordinate system is not equatorial, then
957 * wcsprm::equinox will be marked as undefined.
958 *
959 * alt const char*
960 * Character code for alternate coordinate descriptions
961 * (i.e. the 'a' in keyword names such as CTYPEia). This
962 * is blank for the primary coordinate description, or
963 * one of the 26 upper-case letters, A-Z. May be set to
964 * the null pointer, or null string if no change is
965 * required.
966 *
967 * Function return value:
968 * int Status return value:
969 * 0: Success.
970 * 1: Null wcsprm pointer passed.
971 * 12: Invalid subimage specification (no celestial
972 * axes).
973 *
974 * Notes:
975 * 1: Follows the prescription given in WCS Paper II, Sect. 2.7 for changing
976 * celestial coordinates.
977 *
978 * The implementation takes account of indeterminacies that arise in that
979 * prescription in the particular cases where one of the poles of the new
980 * system is at the fiducial point, or one of them is at the native pole.
981 *
982 * 2: If lat2p1 == +90, i.e. where the poles of the two coordinate systems
983 * coincide, then the spherical coordinate transformation becomes a simple
984 * change in origin of longitude given by
985 * lng2 = lng1 + (lng2p1 - lng1p2 - 180), and lat2 = lat1, where
986 * (lng2,lat2) are coordinates in the new system, and (lng1,lat1) are
987 * coordinates in the original system.
988 *
989 * Likewise, if lat2p1 == -90, then lng2 = -lng1 + (lng2p1 + lng1p2), and
990 * lat2 = -lat1.
991 *
992 * 3: For example, if the original coordinate system is B1950 equatorial and
993 * the desired new coordinate system is galactic, then
994 *
995 * - (lng2p1,lat2p1) are the galactic coordinates of the B1950 celestial
996 * pole, defined by the IAU to be (123.0,+27.4), and lng1p2 is the B1950
997 * right ascension of the galactic pole, defined as 192.25. Clearly
998 * these coordinates are fixed for a particular coordinate
999 * transformation.
1000 *
1001 * - (clng,clat) would be 'GLON' and 'GLAT', these being the FITS standard
1002 * identifiers for galactic coordinates.
1003 *
1004 * - Since the new coordinate system is not equatorial, wcsprm::radesys
1005 * and wcsprm::equinox will be cleared.
1006 *
1007 * 4. The coordinates required for some common transformations (obtained from
1008 * https://ned.ipac.caltech.edu/coordinate_calculator) are as follows:
1009 *
1010 = (123.0000,+27.4000) galactic coordinates of B1950 celestial pole,
1011 = (192.2500,+27.4000) B1950 equatorial coordinates of galactic pole.
1012 *
1013 = (122.9319,+27.1283) galactic coordinates of J2000 celestial pole,
1014 = (192.8595,+27.1283) J2000 equatorial coordinates of galactic pole.
1015 *
1016 = (359.6774,+89.7217) B1950 equatorial coordinates of J2000 pole,
1017 = (180.3162,+89.7217) J2000 equatorial coordinates of B1950 pole.
1018 *
1019 = (270.0000,+66.5542) B1950 equatorial coordinates of B1950 ecliptic pole,
1020 = ( 90.0000,+66.5542) B1950 ecliptic coordinates of B1950 celestial pole.
1021 *
1022 = (270.0000,+66.5607) J2000 equatorial coordinates of J2000 ecliptic pole,
1023 = ( 90.0000,+66.5607) J2000 ecliptic coordinates of J2000 celestial pole.
1024 *
1025 = ( 26.7315,+15.6441) supergalactic coordinates of B1950 celestial pole,
1026 = (283.1894,+15.6441) B1950 equatorial coordinates of supergalactic pole.
1027 *
1028 = ( 26.4505,+15.7089) supergalactic coordinates of J2000 celestial pole,
1029 = (283.7542,+15.7089) J2000 equatorial coordinates of supergalactic pole.
1030 *
1031 *
1032 * wcssptr() - Spectral axis translation
1033 * -------------------------------------
1034 * wcssptr() translates the spectral axis in a wcsprm struct. For example, a
1035 * 'FREQ' axis may be translated into 'ZOPT-F2W' and vice versa.
1036 *
1037 * PLEASE NOTE: Information in the wcsprm struct relating to the original
1038 * coordinate system will be overwritten and therefore lost. If this is
1039 * undesirable, invoke wcssptr() on a copy of the struct made with wcssub().
1040 * The wcsprm struct is reset on return with an explicit call to wcsset().
1041 *
1042 * Given and returned:
1043 * wcs struct wcsprm*
1044 * Coordinate transformation parameters.
1045 *
1046 * i int* Index of the spectral axis (0-relative). If given < 0
1047 * it will be set to the first spectral axis identified
1048 * from the ctype[] keyvalues in the wcsprm struct.
1049 *
1050 * ctype char[9] Desired spectral CTYPEia. Wildcarding may be used as
1051 * for the ctypeS2 argument to spctrn() as described in
1052 * the prologue of spc.h, i.e. if the final three
1053 * characters are specified as "???", or if just the
1054 * eighth character is specified as '?', the correct
1055 * algorithm code will be substituted and returned.
1056 *
1057 * Function return value:
1058 * int Status return value:
1059 * 0: Success.
1060 * 1: Null wcsprm pointer passed.
1061 * 2: Memory allocation failed.
1062 * 3: Linear transformation matrix is singular.
1063 * 4: Inconsistent or unrecognized coordinate axis
1064 * types.
1065 * 5: Invalid parameter value.
1066 * 6: Invalid coordinate transformation parameters.
1067 * 7: Ill-conditioned coordinate transformation
1068 * parameters.
1069 * 12: Invalid subimage specification (no spectral
1070 * axis).
1071 *
1072 * For returns > 1, a detailed error message is set in
1073 * wcsprm::err if enabled, see wcserr_enable().
1074 *
1075 *
1076 * wcslib_version() - WCSLIB version number
1077 * ----------------------------------------
1078 * wcslib_version() returns the WCSLIB version number.
1079 *
1080 * The major version number changes when the ABI changes or when the license
1081 * conditions change. ABI changes typically result from a change to the
1082 * contents of one of the structs. The major version number is used to
1083 * distinguish between incompatible versions of the sharable library.
1084 *
1085 * The minor version number changes with new functionality or bug fixes that do
1086 * not involve a change in the ABI.
1087 *
1088 * The auxiliary version number (which is often absent) signals changes to the
1089 * documentation, test suite, build procedures, or any other change that does
1090 * not affect the compiled library.
1091 *
1092 * Returned:
1093 * vers[3] int[3] The broken-down version number:
1094 * 0: Major version number.
1095 * 1: Minor version number.
1096 * 2: Auxiliary version number (zero if absent).
1097 * May be given as a null pointer if not required.
1098 *
1099 * Function return value:
1100 * char* A null-terminated, statically allocated string
1101 * containing the version number in the usual form, i.e.
1102 * "<major>.<minor>.<auxiliary>".
1103 *
1104 *
1105 * wcsprm struct - Coordinate transformation parameters
1106 * ----------------------------------------------------
1107 * The wcsprm struct contains information required to transform world
1108 * coordinates. It consists of certain members that must be set by the user
1109 * ("given") and others that are set by the WCSLIB routines ("returned").
1110 * While the addresses of the arrays themselves may be set by wcsinit() if it
1111 * (optionally) allocates memory, their contents must be set by the user.
1112 *
1113 * Some parameters that are given are not actually required for transforming
1114 * coordinates. These are described as "auxiliary"; the struct simply provides
1115 * a place to store them, though they may be used by wcshdo() in constructing a
1116 * FITS header from a wcsprm struct. Some of the returned values are supplied
1117 * for informational purposes and others are for internal use only as
1118 * indicated.
1119 *
1120 * In practice, it is expected that a WCS parser would scan the FITS header to
1121 * determine the number of coordinate axes. It would then use wcsinit() to
1122 * allocate memory for arrays in the wcsprm struct and set default values.
1123 * Then as it reread the header and identified each WCS keyrecord it would load
1124 * the value into the relevant wcsprm array element. This is essentially what
1125 * wcspih() does - refer to the prologue of wcshdr.h. As the final step,
1126 * wcsset() is invoked, either directly or indirectly, to set the derived
1127 * members of the wcsprm struct. wcsset() strips off trailing blanks in all
1128 * string members and null-fills the character array.
1129 *
1130 * int flag
1131 * (Given and returned) This flag must be set to zero whenever any of the
1132 * following wcsprm struct members are set or changed:
1133 *
1134 * - wcsprm::naxis (q.v., not normally set by the user),
1135 * - wcsprm::crpix,
1136 * - wcsprm::pc,
1137 * - wcsprm::cdelt,
1138 * - wcsprm::crval,
1139 * - wcsprm::cunit,
1140 * - wcsprm::ctype,
1141 * - wcsprm::lonpole,
1142 * - wcsprm::latpole,
1143 * - wcsprm::restfrq,
1144 * - wcsprm::restwav,
1145 * - wcsprm::npv,
1146 * - wcsprm::pv,
1147 * - wcsprm::nps,
1148 * - wcsprm::ps,
1149 * - wcsprm::cd,
1150 * - wcsprm::crota,
1151 * - wcsprm::altlin,
1152 * - wcsprm::ntab,
1153 * - wcsprm::nwtb,
1154 * - wcsprm::tab,
1155 * - wcsprm::wtb.
1156 *
1157 * This signals the initialization routine, wcsset(), to recompute the
1158 * returned members of the linprm, celprm, spcprm, and tabprm structs.
1159 * wcsset() will reset flag to indicate that this has been done.
1160 *
1161 * PLEASE NOTE: flag should be set to -1 when wcsinit() is called for the
1162 * first time for a particular wcsprm struct in order to initialize memory
1163 * management. It must ONLY be used on the first initialization otherwise
1164 * memory leaks may result.
1165 *
1166 * int naxis
1167 * (Given or returned) Number of pixel and world coordinate elements.
1168 *
1169 * If wcsinit() is used to initialize the linprm struct (as would normally
1170 * be the case) then it will set naxis from the value passed to it as a
1171 * function argument. The user should not subsequently modify it.
1172 *
1173 * double *crpix
1174 * (Given) Address of the first element of an array of double containing
1175 * the coordinate reference pixel, CRPIXja.
1176 *
1177 * double *pc
1178 * (Given) Address of the first element of the PCi_ja (pixel coordinate)
1179 * transformation matrix. The expected order is
1180 *
1181 = struct wcsprm wcs;
1182 = wcs.pc = {PC1_1, PC1_2, PC2_1, PC2_2};
1183 *
1184 * This may be constructed conveniently from a 2-D array via
1185 *
1186 = double m[2][2] = {{PC1_1, PC1_2},
1187 = {PC2_1, PC2_2}};
1188 *
1189 * which is equivalent to
1190 *
1191 = double m[2][2];
1192 = m[0][0] = PC1_1;
1193 = m[0][1] = PC1_2;
1194 = m[1][0] = PC2_1;
1195 = m[1][1] = PC2_2;
1196 *
1197 * The storage order for this 2-D array is the same as for the 1-D array,
1198 * whence
1199 *
1200 = wcs.pc = *m;
1201 *
1202 * would be legitimate.
1203 *
1204 * double *cdelt
1205 * (Given) Address of the first element of an array of double containing
1206 * the coordinate increments, CDELTia.
1207 *
1208 * double *crval
1209 * (Given) Address of the first element of an array of double containing
1210 * the coordinate reference values, CRVALia.
1211 *
1212 * char (*cunit)[72]
1213 * (Given) Address of the first element of an array of char[72] containing
1214 * the CUNITia keyvalues which define the units of measurement of the
1215 * CRVALia, CDELTia, and CDi_ja keywords.
1216 *
1217 * As CUNITia is an optional header keyword, cunit[][72] may be left blank
1218 * but otherwise is expected to contain a standard units specification as
1219 * defined by WCS Paper I. Utility function wcsutrn(), described in
1220 * wcsunits.h, is available to translate commonly used non-standard units
1221 * specifications but this must be done as a separate step before invoking
1222 * wcsset().
1223 *
1224 * For celestial axes, if cunit[][72] is not blank, wcsset() uses
1225 * wcsunits() to parse it and scale cdelt[], crval[], and cd[][*] to
1226 * degrees. It then resets cunit[][72] to "deg".
1227 *
1228 * For spectral axes, if cunit[][72] is not blank, wcsset() uses wcsunits()
1229 * to parse it and scale cdelt[], crval[], and cd[][*] to SI units. It
1230 * then resets cunit[][72] accordingly.
1231 *
1232 * wcsset() ignores cunit[][72] for other coordinate types; cunit[][72] may
1233 * be used to label coordinate values.
1234 *
1235 * These variables accomodate the longest allowed string-valued FITS
1236 * keyword, being limited to 68 characters, plus the null-terminating
1237 * character.
1238 *
1239 * char (*ctype)[72]
1240 * (Given) Address of the first element of an array of char[72] containing
1241 * the coordinate axis types, CTYPEia.
1242 *
1243 * The ctype[][72] keyword values must be in upper case and there must be
1244 * zero or one pair of matched celestial axis types, and zero or one
1245 * spectral axis. The ctype[][72] strings should be padded with blanks on
1246 * the right and null-terminated so that they are at least eight characters
1247 * in length.
1248 *
1249 * These variables accomodate the longest allowed string-valued FITS
1250 * keyword, being limited to 68 characters, plus the null-terminating
1251 * character.
1252 *
1253 * double lonpole
1254 * (Given and returned) The native longitude of the celestial pole, phi_p,
1255 * given by LONPOLEa [deg] or by PVi_2a [deg] attached to the longitude
1256 * axis which takes precedence if defined, and ...
1257 * double latpole
1258 * (Given and returned) ... the native latitude of the celestial pole,
1259 * theta_p, given by LATPOLEa [deg] or by PVi_3a [deg] attached to the
1260 * longitude axis which takes precedence if defined.
1261 *
1262 * lonpole and latpole may be left to default to values set by wcsinit()
1263 * (see celprm::ref), but in any case they will be reset by wcsset() to
1264 * the values actually used. Note therefore that if the wcsprm struct is
1265 * reused without resetting them, whether directly or via wcsinit(), they
1266 * will no longer have their default values.
1267 *
1268 * double restfrq
1269 * (Given) The rest frequency [Hz], and/or ...
1270 * double restwav
1271 * (Given) ... the rest wavelength in vacuo [m], only one of which need be
1272 * given, the other should be set to zero.
1273 *
1274 * int npv
1275 * (Given) The number of entries in the wcsprm::pv[] array.
1276 *
1277 * int npvmax
1278 * (Given or returned) The length of the wcsprm::pv[] array.
1279 *
1280 * npvmax will be set by wcsinit() if it allocates memory for wcsprm::pv[],
1281 * otherwise it must be set by the user. See also wcsnpv().
1282 *
1283 * struct pvcard *pv
1284 * (Given) Address of the first element of an array of length npvmax of
1285 * pvcard structs.
1286 *
1287 * As a FITS header parser encounters each PVi_ma keyword it should load it
1288 * into a pvcard struct in the array and increment npv. wcsset()
1289 * interprets these as required.
1290 *
1291 * Note that, if they were not given, wcsset() resets the entries for
1292 * PVi_1a, PVi_2a, PVi_3a, and PVi_4a for longitude axis i to match
1293 * phi_0 and theta_0 (the native longitude and latitude of the reference
1294 * point), LONPOLEa and LATPOLEa respectively.
1295 *
1296 * int nps
1297 * (Given) The number of entries in the wcsprm::ps[] array.
1298 *
1299 * int npsmax
1300 * (Given or returned) The length of the wcsprm::ps[] array.
1301 *
1302 * npsmax will be set by wcsinit() if it allocates memory for wcsprm::ps[],
1303 * otherwise it must be set by the user. See also wcsnps().
1304 *
1305 * struct pscard *ps
1306 * (Given) Address of the first element of an array of length npsmax of
1307 * pscard structs.
1308 *
1309 * As a FITS header parser encounters each PSi_ma keyword it should load it
1310 * into a pscard struct in the array and increment nps. wcsset()
1311 * interprets these as required (currently no PSi_ma keyvalues are
1312 * recognized).
1313 *
1314 * double *cd
1315 * (Given) For historical compatibility, the wcsprm struct supports two
1316 * alternate specifications of the linear transformation matrix, those
1317 * associated with the CDi_ja keywords, and ...
1318 * double *crota
1319 * (Given) ... those associated with the CROTAi keywords. Although these
1320 * may not formally co-exist with PCi_ja, the approach taken here is simply
1321 * to ignore them if given in conjunction with PCi_ja.
1322 *
1323 * int altlin
1324 * (Given) altlin is a bit flag that denotes which of the PCi_ja, CDi_ja
1325 * and CROTAi keywords are present in the header:
1326 *
1327 * - Bit 0: PCi_ja is present.
1328 *
1329 * - Bit 1: CDi_ja is present.
1330 *
1331 * Matrix elements in the IRAF convention are equivalent to the product
1332 * CDi_ja = CDELTia * PCi_ja, but the defaults differ from that of the
1333 * PCi_ja matrix. If one or more CDi_ja keywords are present then all
1334 * unspecified CDi_ja default to zero. If no CDi_ja (or CROTAi) keywords
1335 * are present, then the header is assumed to be in PCi_ja form whether
1336 * or not any PCi_ja keywords are present since this results in an
1337 * interpretation of CDELTia consistent with the original FITS
1338 * specification.
1339 *
1340 * While CDi_ja may not formally co-exist with PCi_ja, it may co-exist
1341 * with CDELTia and CROTAi which are to be ignored.
1342 *
1343 * - Bit 2: CROTAi is present.
1344 *
1345 * In the AIPS convention, CROTAi may only be associated with the
1346 * latitude axis of a celestial axis pair. It specifies a rotation in
1347 * the image plane that is applied AFTER the CDELTia; any other CROTAi
1348 * keywords are ignored.
1349 *
1350 * CROTAi may not formally co-exist with PCi_ja.
1351 *
1352 * CROTAi and CDELTia may formally co-exist with CDi_ja but if so are to
1353 * be ignored.
1354 *
1355 * - Bit 3: PCi_ja + CDELTia was derived from CDi_ja by wcspcx().
1356 *
1357 * This bit is set by wcspcx() when it derives PCi_ja and CDELTia from
1358 * CDi_ja via an orthonormal decomposition. In particular, it signals
1359 * wcsset() not to replace PCi_ja by a copy of CDi_ja with CDELTia set
1360 * to unity.
1361 *
1362 * CDi_ja and CROTAi keywords, if found, are to be stored in the wcsprm::cd
1363 * and wcsprm::crota arrays which are dimensioned similarly to wcsprm::pc
1364 * and wcsprm::cdelt. FITS header parsers should use the following
1365 * procedure:
1366 *
1367 * - Whenever a PCi_ja keyword is encountered: altlin |= 1;
1368 *
1369 * - Whenever a CDi_ja keyword is encountered: altlin |= 2;
1370 *
1371 * - Whenever a CROTAi keyword is encountered: altlin |= 4;
1372 *
1373 * If none of these bits are set the PCi_ja representation results, i.e.
1374 * wcsprm::pc and wcsprm::cdelt will be used as given.
1375 *
1376 * These alternate specifications of the linear transformation matrix are
1377 * translated immediately to PCi_ja by wcsset() and are invisible to the
1378 * lower-level WCSLIB routines. In particular, unless bit 3 is also set,
1379 * wcsset() resets wcsprm::cdelt to unity if CDi_ja is present (and no
1380 * PCi_ja).
1381 *
1382 * If CROTAi are present but none is associated with the latitude axis
1383 * (and no PCi_ja or CDi_ja), then wcsset() reverts to a unity PCi_ja
1384 * matrix.
1385 *
1386 * int velref
1387 * (Given) AIPS velocity code VELREF, refer to spcaips().
1388 *
1389 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1390 * wcsprm::velref is changed.
1391 *
1392 * char alt[4]
1393 * (Given, auxiliary) Character code for alternate coordinate descriptions
1394 * (i.e. the 'a' in keyword names such as CTYPEia). This is blank for the
1395 * primary coordinate description, or one of the 26 upper-case letters,
1396 * A-Z.
1397 *
1398 * An array of four characters is provided for alignment purposes, only the
1399 * first is used.
1400 *
1401 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1402 * wcsprm::alt is changed.
1403 *
1404 * int colnum
1405 * (Given, auxiliary) Where the coordinate representation is associated
1406 * with an image-array column in a FITS binary table, this variable may be
1407 * used to record the relevant column number.
1408 *
1409 * It should be set to zero for an image header or pixel list.
1410 *
1411 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1412 * wcsprm::colnum is changed.
1413 *
1414 * int *colax
1415 * (Given, auxiliary) Address of the first element of an array of int
1416 * recording the column numbers for each axis in a pixel list.
1417 *
1418 * The array elements should be set to zero for an image header or image
1419 * array in a binary table.
1420 *
1421 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1422 * wcsprm::colax is changed.
1423 *
1424 * char (*cname)[72]
1425 * (Given, auxiliary) The address of the first element of an array of
1426 * char[72] containing the coordinate axis names, CNAMEia.
1427 *
1428 * These variables accomodate the longest allowed string-valued FITS
1429 * keyword, being limited to 68 characters, plus the null-terminating
1430 * character.
1431 *
1432 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1433 * wcsprm::cname is changed.
1434 *
1435 * double *crder
1436 * (Given, auxiliary) Address of the first element of an array of double
1437 * recording the random error in the coordinate value, CRDERia.
1438 *
1439 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1440 * wcsprm::crder is changed.
1441 *
1442 * double *csyer
1443 * (Given, auxiliary) Address of the first element of an array of double
1444 * recording the systematic error in the coordinate value, CSYERia.
1445 *
1446 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1447 * wcsprm::csyer is changed.
1448 *
1449 * double *czphs
1450 * (Given, auxiliary) Address of the first element of an array of double
1451 * recording the time at the zero point of a phase axis, CZPHSia.
1452 *
1453 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1454 * wcsprm::czphs is changed.
1455 *
1456 * double *cperi
1457 * (Given, auxiliary) Address of the first element of an array of double
1458 * recording the period of a phase axis, CPERIia.
1459 *
1460 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1461 * wcsprm::cperi is changed.
1462 *
1463 * char wcsname[72]
1464 * (Given, auxiliary) The name given to the coordinate representation,
1465 * WCSNAMEa. This variable accomodates the longest allowed string-valued
1466 * FITS keyword, being limited to 68 characters, plus the null-terminating
1467 * character.
1468 *
1469 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1470 * wcsprm::wcsname is changed.
1471 *
1472 * char timesys[72]
1473 * (Given, auxiliary) TIMESYS keyvalue, being the time scale (UTC, TAI,
1474 * etc.) in which all other time-related auxiliary header values are
1475 * recorded. Also defines the time scale for an image axis with CTYPEia
1476 * set to 'TIME'.
1477 *
1478 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1479 * wcsprm::timesys is changed.
1480 *
1481 * char trefpos[72]
1482 * (Given, auxiliary) TREFPOS keyvalue, being the location in space where
1483 * the recorded time is valid.
1484 *
1485 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1486 * wcsprm::trefpos is changed.
1487 *
1488 * char trefdir[72]
1489 * (Given, auxiliary) TREFDIR keyvalue, being the reference direction used
1490 * in calculating a pathlength delay.
1491 *
1492 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1493 * wcsprm::trefdir is changed.
1494 *
1495 * char plephem[72]
1496 * (Given, auxiliary) PLEPHEM keyvalue, being the Solar System ephemeris
1497 * used for calculating a pathlength delay.
1498 *
1499 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1500 * wcsprm::plephem is changed.
1501 *
1502 * char timeunit[72]
1503 * (Given, auxiliary) TIMEUNIT keyvalue, being the time units in which
1504 * the following header values are expressed: TSTART, TSTOP, TIMEOFFS,
1505 * TIMSYER, TIMRDER, TIMEDEL. It also provides the default value for
1506 * CUNITia for time axes.
1507 *
1508 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1509 * wcsprm::timeunit is changed.
1510 *
1511 * char dateref[72]
1512 * (Given, auxiliary) DATEREF keyvalue, being the date of a reference epoch
1513 * relative to which other time measurements refer.
1514 *
1515 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1516 * wcsprm::dateref is changed.
1517 *
1518 * double mjdref[2]
1519 * (Given, auxiliary) MJDREF keyvalue, equivalent to DATEREF expressed as
1520 * a Modified Julian Date (MJD = JD - 2400000.5). The value is given as
1521 * the sum of the two-element vector, allowing increased precision.
1522 *
1523 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1524 * wcsprm::mjdref is changed.
1525 *
1526 * double timeoffs
1527 * (Given, auxiliary) TIMEOFFS keyvalue, being a time offset, which may be
1528 * used, for example, to provide a uniform clock correction for times
1529 * referenced to DATEREF.
1530 *
1531 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1532 * wcsprm::timeoffs is changed.
1533 *
1534 * char dateobs[72]
1535 * (Given, auxiliary) DATE-OBS keyvalue, being the date at the start of the
1536 * observation unless otherwise explained in the DATE-OBS keycomment, in
1537 * ISO format, yyyy-mm-ddThh:mm:ss.
1538 *
1539 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1540 * wcsprm::dateobs is changed.
1541 *
1542 * char datebeg[72]
1543 * (Given, auxiliary) DATE-BEG keyvalue, being the date at the start of the
1544 * observation in ISO format, yyyy-mm-ddThh:mm:ss.
1545 *
1546 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1547 * wcsprm::datebeg is changed.
1548 *
1549 * char dateavg[72]
1550 * (Given, auxiliary) DATE-AVG keyvalue, being the date at a representative
1551 * mid-point of the 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::dateavg is changed.
1555 *
1556 * char dateend[72]
1557 * (Given, auxiliary) DATE-END keyvalue, baing the date at the end of the
1558 * 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::dateend is changed.
1562 *
1563 * double mjdobs
1564 * (Given, auxiliary) MJD-OBS keyvalue, equivalent to DATE-OBS expressed
1565 * as a Modified Julian Date (MJD = JD - 2400000.5).
1566 *
1567 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1568 * wcsprm::mjdobs is changed.
1569 *
1570 * double mjdbeg
1571 * (Given, auxiliary) MJD-BEG keyvalue, equivalent to DATE-BEG 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::mjdbeg is changed.
1576 *
1577 * double mjdavg
1578 * (Given, auxiliary) MJD-AVG keyvalue, equivalent to DATE-AVG 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::mjdavg is changed.
1583 *
1584 * double mjdend
1585 * (Given, auxiliary) MJD-END keyvalue, equivalent to DATE-END 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::mjdend is changed.
1590 *
1591 * double jepoch
1592 * (Given, auxiliary) JEPOCH keyvalue, equivalent to DATE-OBS expressed
1593 * as a Julian epoch.
1594 *
1595 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1596 * wcsprm::jepoch is changed.
1597 *
1598 * double bepoch
1599 * (Given, auxiliary) BEPOCH keyvalue, equivalent to DATE-OBS expressed
1600 * as a Besselian epoch
1601 *
1602 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1603 * wcsprm::bepoch is changed.
1604 *
1605 * double tstart
1606 * (Given, auxiliary) TSTART keyvalue, equivalent to DATE-BEG expressed
1607 * as a time in units of TIMEUNIT relative to DATEREF+TIMEOFFS.
1608 *
1609 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1610 * wcsprm::tstart is changed.
1611 *
1612 * double tstop
1613 * (Given, auxiliary) TSTOP keyvalue, equivalent to DATE-END 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::tstop is changed.
1618 *
1619 * double xposure
1620 * (Given, auxiliary) XPOSURE keyvalue, being the effective exposure time
1621 * in units of TIMEUNIT.
1622 *
1623 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1624 * wcsprm::xposure is changed.
1625 *
1626 * double telapse
1627 * (Given, auxiliary) TELAPSE keyvalue, equivalent to the elapsed time
1628 * between DATE-BEG and DATE-END, in units of TIMEUNIT.
1629 *
1630 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1631 * wcsprm::telapse is changed.
1632 *
1633 * double timsyer
1634 * (Given, auxiliary) TIMSYER keyvalue, being the absolute error of the
1635 * time values, in units of TIMEUNIT.
1636 *
1637 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1638 * wcsprm::timsyer is changed.
1639 *
1640 * double timrder
1641 * (Given, auxiliary) TIMRDER keyvalue, being the accuracy of time stamps
1642 * relative to each other, in units of TIMEUNIT.
1643 *
1644 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1645 * wcsprm::timrder is changed.
1646 *
1647 * double timedel
1648 * (Given, auxiliary) TIMEDEL keyvalue, being the resolution of the time
1649 * stamps.
1650 *
1651 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1652 * wcsprm::timedel is changed.
1653 *
1654 * double timepixr
1655 * (Given, auxiliary) TIMEPIXR keyvalue, being the relative position of the
1656 * time stamps in binned time intervals, a value between 0.0 and 1.0.
1657 *
1658 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1659 * wcsprm::timepixr is changed.
1660 *
1661 * double obsgeo[6]
1662 * (Given, auxiliary) Location of the observer in a standard terrestrial
1663 * reference frame. The first three give ITRS Cartesian coordinates
1664 * OBSGEO-X [m], OBSGEO-Y [m], OBSGEO-Z [m], and the second three give
1665 * OBSGEO-L [deg], OBSGEO-B [deg], OBSGEO-H [m], which are related through
1666 * a standard transformation.
1667 *
1668 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1669 * wcsprm::obsgeo is changed.
1670 *
1671 * char obsorbit[72]
1672 * (Given, auxiliary) OBSORBIT keyvalue, being the URI, URL, or name of an
1673 * orbit ephemeris file giving spacecraft coordinates relating to TREFPOS.
1674 *
1675 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1676 * wcsprm::obsorbit is changed.
1677 *
1678 * char radesys[72]
1679 * (Given, auxiliary) The equatorial or ecliptic coordinate system type,
1680 * RADESYSa.
1681 *
1682 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1683 * wcsprm::radesys is changed.
1684 *
1685 * double equinox
1686 * (Given, auxiliary) The equinox associated with dynamical equatorial or
1687 * ecliptic coordinate systems, EQUINOXa (or EPOCH in older headers). Not
1688 * applicable to ICRS equatorial or ecliptic coordinates.
1689 *
1690 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1691 * wcsprm::equinox is changed.
1692 *
1693 * char specsys[72]
1694 * (Given, auxiliary) Spectral reference frame (standard of rest),
1695 * SPECSYSa.
1696 *
1697 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1698 * wcsprm::specsys is changed.
1699 *
1700 * char ssysobs[72]
1701 * (Given, auxiliary) The spectral reference frame in which there is no
1702 * differential variation in the spectral coordinate across the
1703 * field-of-view, SSYSOBSa.
1704 *
1705 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1706 * wcsprm::ssysobs is changed.
1707 *
1708 * double velosys
1709 * (Given, auxiliary) The relative radial velocity [m/s] between the
1710 * observer and the selected standard of rest in the direction of the
1711 * celestial reference coordinate, VELOSYSa.
1712 *
1713 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1714 * wcsprm::velosys is changed.
1715 *
1716 * double zsource
1717 * (Given, auxiliary) The redshift, ZSOURCEa, of the source.
1718 *
1719 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1720 * wcsprm::zsource is changed.
1721 *
1722 * char ssyssrc[72]
1723 * (Given, auxiliary) The spectral reference frame (standard of rest),
1724 * SSYSSRCa, in which wcsprm::zsource was measured.
1725 *
1726 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1727 * wcsprm::ssyssrc is changed.
1728 *
1729 * double velangl
1730 * (Given, auxiliary) The angle [deg] that should be used to decompose an
1731 * observed velocity into radial and transverse components.
1732 *
1733 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1734 * wcsprm::velangl is changed.
1735 *
1736 * struct auxprm *aux
1737 * (Given, auxiliary) This struct holds auxiliary coordinate system
1738 * information of a specialist nature. While these parameters may be
1739 * widely recognized within particular fields of astronomy, they differ
1740 * from the above auxiliary parameters in not being defined by any of the
1741 * FITS WCS standards. Collecting them together in a separate struct that
1742 * is allocated only when required helps to control bloat in the size of
1743 * the wcsprm struct.
1744 *
1745 * int ntab
1746 * (Given) See wcsprm::tab.
1747 *
1748 * int nwtb
1749 * (Given) See wcsprm::wtb.
1750 *
1751 * struct tabprm *tab
1752 * (Given) Address of the first element of an array of ntab tabprm structs
1753 * for which memory has been allocated. These are used to store tabular
1754 * transformation parameters.
1755 *
1756 * Although technically wcsprm::ntab and tab are "given", they will
1757 * normally be set by invoking wcstab(), whether directly or indirectly.
1758 *
1759 * The tabprm structs contain some members that must be supplied and others
1760 * that are derived. The information to be supplied comes primarily from
1761 * arrays stored in one or more FITS binary table extensions. These
1762 * arrays, referred to here as "wcstab arrays", are themselves located by
1763 * parameters stored in the FITS image header.
1764 *
1765 * struct wtbarr *wtb
1766 * (Given) Address of the first element of an array of nwtb wtbarr structs
1767 * for which memory has been allocated. These are used in extracting
1768 * wcstab arrays from a FITS binary table.
1769 *
1770 * Although technically wcsprm::nwtb and wtb are "given", they will
1771 * normally be set by invoking wcstab(), whether directly or indirectly.
1772 *
1773 * char lngtyp[8]
1774 * (Returned) Four-character WCS celestial longitude and ...
1775 * char lattyp[8]
1776 * (Returned) ... latitude axis types. e.g. "RA", "DEC", "GLON", "GLAT",
1777 * etc. extracted from 'RA--', 'DEC-', 'GLON', 'GLAT', etc. in the first
1778 * four characters of CTYPEia but with trailing dashes removed. (Declared
1779 * as char[8] for alignment reasons.)
1780 *
1781 * int lng
1782 * (Returned) Index for the longitude coordinate, and ...
1783 * int lat
1784 * (Returned) ... index for the latitude coordinate, and ...
1785 * int spec
1786 * (Returned) ... index for the spectral coordinate in the imgcrd[][] and
1787 * world[][] arrays in the API of wcsp2s(), wcss2p() and wcsmix().
1788 *
1789 * These may also serve as indices into the pixcrd[][] array provided that
1790 * the PCi_ja matrix does not transpose axes.
1791 *
1792 * int cubeface
1793 * (Returned) Index into the pixcrd[][] array for the CUBEFACE axis. This
1794 * is used for quadcube projections where the cube faces are stored on a
1795 * separate axis (see wcs.h).
1796 *
1797 * int *types
1798 * (Returned) Address of the first element of an array of int containing a
1799 * four-digit type code for each axis.
1800 *
1801 * - First digit (i.e. 1000s):
1802 * - 0: Non-specific coordinate type.
1803 * - 1: Stokes coordinate.
1804 * - 2: Celestial coordinate (including CUBEFACE).
1805 * - 3: Spectral coordinate.
1806 *
1807 * - Second digit (i.e. 100s):
1808 * - 0: Linear axis.
1809 * - 1: Quantized axis (STOKES, CUBEFACE).
1810 * - 2: Non-linear celestial axis.
1811 * - 3: Non-linear spectral axis.
1812 * - 4: Logarithmic axis.
1813 * - 5: Tabular axis.
1814 *
1815 * - Third digit (i.e. 10s):
1816 * - 0: Group number, e.g. lookup table number, being an index into the
1817 * tabprm array (see above).
1818 *
1819 * - The fourth digit is used as a qualifier depending on the axis type.
1820 *
1821 * - For celestial axes:
1822 * - 0: Longitude coordinate.
1823 * - 1: Latitude coordinate.
1824 * - 2: CUBEFACE number.
1825 *
1826 * - For lookup tables: the axis number in a multidimensional table.
1827 *
1828 * CTYPEia in "4-3" form with unrecognized algorithm code will have its
1829 * type set to -1 and generate an error.
1830 *
1831 * struct linprm lin
1832 * (Returned) Linear transformation parameters (usage is described in the
1833 * prologue to lin.h).
1834 *
1835 * struct celprm cel
1836 * (Returned) Celestial transformation parameters (usage is described in
1837 * the prologue to cel.h).
1838 *
1839 * struct spcprm spc
1840 * (Returned) Spectral transformation parameters (usage is described in the
1841 * prologue to spc.h).
1842 *
1843 * struct wcserr *err
1844 * (Returned) If enabled, when an error status is returned, this struct
1845 * contains detailed information about the error, see wcserr_enable().
1846 *
1847 * int m_flag
1848 * (For internal use only.)
1849 * int m_naxis
1850 * (For internal use only.)
1851 * double *m_crpix
1852 * (For internal use only.)
1853 * double *m_pc
1854 * (For internal use only.)
1855 * double *m_cdelt
1856 * (For internal use only.)
1857 * double *m_crval
1858 * (For internal use only.)
1859 * char (*m_cunit)[72]
1860 * (For internal use only.)
1861 * char (*m_ctype)[72]
1862 * (For internal use only.)
1863 * struct pvcard *m_pv
1864 * (For internal use only.)
1865 * struct pscard *m_ps
1866 * (For internal use only.)
1867 * double *m_cd
1868 * (For internal use only.)
1869 * double *m_crota
1870 * (For internal use only.)
1871 * int *m_colax
1872 * (For internal use only.)
1873 * char (*m_cname)[72]
1874 * (For internal use only.)
1875 * double *m_crder
1876 * (For internal use only.)
1877 * double *m_csyer
1878 * (For internal use only.)
1879 * double *m_czphs
1880 * (For internal use only.)
1881 * double *m_cperi
1882 * (For internal use only.)
1883 * struct tabprm *m_tab
1884 * (For internal use only.)
1885 * struct wtbarr *m_wtb
1886 * (For internal use only.)
1887 *
1888 *
1889 * pvcard struct - Store for PVi_ma keyrecords
1890 * -------------------------------------------
1891 * The pvcard struct is used to pass the parsed contents of PVi_ma keyrecords
1892 * to wcsset() via the wcsprm struct.
1893 *
1894 * All members of this struct are to be set by the user.
1895 *
1896 * int i
1897 * (Given) Axis number (1-relative), as in the FITS PVi_ma keyword. If
1898 * i == 0, wcsset() will replace it with the latitude axis number.
1899 *
1900 * int m
1901 * (Given) Parameter number (non-negative), as in the FITS PVi_ma keyword.
1902 *
1903 * double value
1904 * (Given) Parameter value.
1905 *
1906 *
1907 * pscard struct - Store for PSi_ma keyrecords
1908 * -------------------------------------------
1909 * The pscard struct is used to pass the parsed contents of PSi_ma keyrecords
1910 * to wcsset() via the wcsprm struct.
1911 *
1912 * All members of this struct are to be set by the user.
1913 *
1914 * int i
1915 * (Given) Axis number (1-relative), as in the FITS PSi_ma keyword.
1916 *
1917 * int m
1918 * (Given) Parameter number (non-negative), as in the FITS PSi_ma keyword.
1919 *
1920 * char value[72]
1921 * (Given) Parameter value.
1922 *
1923 *
1924 * auxprm struct - Additional auxiliary parameters
1925 * -----------------------------------------------
1926 * The auxprm struct holds auxiliary coordinate system information of a
1927 * specialist nature. It is anticipated that this struct will expand in future
1928 * to accomodate additional parameters.
1929 *
1930 * All members of this struct are to be set by the user.
1931 *
1932 * double rsun_ref
1933 * (Given, auxiliary) Reference radius of the Sun used in coordinate
1934 * calculations (m).
1935 *
1936 * double dsun_obs
1937 * (Given, auxiliary) Distance between the centre of the Sun and the
1938 * observer (m).
1939 *
1940 * double crln_obs
1941 * (Given, auxiliary) Carrington heliographic longitude of the observer
1942 * (deg).
1943 *
1944 * double hgln_obs
1945 * (Given, auxiliary) Stonyhurst heliographic longitude of the observer
1946 * (deg).
1947 *
1948 * double hglt_obs
1949 * (Given, auxiliary) Heliographic latitude (Carrington or Stonyhurst) of
1950 * the observer (deg).
1951 *
1952 *
1953 * Global variable: const char *wcs_errmsg[] - Status return messages
1954 * ------------------------------------------------------------------
1955 * Error messages to match the status value returned from each function.
1956 *
1957 *===========================================================================*/
1958
1959 #ifndef WCSLIB_WCS
1960 #define WCSLIB_WCS
1961
1962 #include "lin.h"
1963 #include "cel.h"
1964 #include "spc.h"
1965
1966 #ifdef __cplusplus
1967 extern "C" {
1968 #define wtbarr wtbarr_s // See prologue of wtbarr.h.
1969 #endif
1970
1971 #define WCSSUB_LONGITUDE 0x1001
1972 #define WCSSUB_LATITUDE 0x1002
1973 #define WCSSUB_CUBEFACE 0x1004
1974 #define WCSSUB_CELESTIAL 0x1007
1975 #define WCSSUB_SPECTRAL 0x1008
1976 #define WCSSUB_STOKES 0x1010
1977
1978
1979 #define WCSCOMPARE_ANCILLARY 0x0001
1980 #define WCSCOMPARE_TILING 0x0002
1981 #define WCSCOMPARE_CRPIX 0x0004
1982
1983
1984 extern const char *wcs_errmsg[];
1985
1986 enum wcs_errmsg_enum {
1987 WCSERR_SUCCESS = 0, // Success.
1988 WCSERR_NULL_POINTER = 1, // Null wcsprm pointer passed.
1989 WCSERR_MEMORY = 2, // Memory allocation failed.
1990 WCSERR_SINGULAR_MTX = 3, // Linear transformation matrix is singular.
1991 WCSERR_BAD_CTYPE = 4, // Inconsistent or unrecognized coordinate
1992 // axis type.
1993 WCSERR_BAD_PARAM = 5, // Invalid parameter value.
1994 WCSERR_BAD_COORD_TRANS = 6, // Unrecognized coordinate transformation
1995 // parameter.
1996 WCSERR_ILL_COORD_TRANS = 7, // Ill-conditioned coordinate transformation
1997 // parameter.
1998 WCSERR_BAD_PIX = 8, // One or more of the pixel coordinates were
1999 // invalid.
2000 WCSERR_BAD_WORLD = 9, // One or more of the world coordinates were
2001 // invalid.
2002 WCSERR_BAD_WORLD_COORD = 10, // Invalid world coordinate.
2003 WCSERR_NO_SOLUTION = 11, // No solution found in the specified
2004 // interval.
2005 WCSERR_BAD_SUBIMAGE = 12, // Invalid subimage specification.
2006 WCSERR_NON_SEPARABLE = 13, // Non-separable subimage coordinate system.
2007 WCSERR_UNSET = 14 // wcsprm struct is unset.
2008 };
2009
2010
2011 // Struct used for storing PVi_ma keywords.
2012 struct pvcard {
2013 int i; // Axis number, as in PVi_ma (1-relative).
2014 int m; // Parameter number, ditto (0-relative).
2015 double value; // Parameter value.
2016 };
2017
2018 // Size of the pvcard struct in int units, used by the Fortran wrappers.
2019 #define PVLEN (sizeof(struct pvcard)/sizeof(int))
2020
2021 // Struct used for storing PSi_ma keywords.
2022 struct pscard {
2023 int i; // Axis number, as in PSi_ma (1-relative).
2024 int m; // Parameter number, ditto (0-relative).
2025 char value[72]; // Parameter value.
2026 };
2027
2028 // Size of the pscard struct in int units, used by the Fortran wrappers.
2029 #define PSLEN (sizeof(struct pscard)/sizeof(int))
2030
2031 // Struct used to hold additional auxiliary parameters.
2032 struct auxprm {
2033 double rsun_ref; // Solar radius.
2034 double dsun_obs; // Distance from Sun centre to observer.
2035 double crln_obs; // Carrington heliographic lng of observer.
2036 double hgln_obs; // Stonyhurst heliographic lng of observer.
2037 double hglt_obs; // Heliographic latitude of observer.
2038 };
2039
2040 // Size of the auxprm struct in int units, used by the Fortran wrappers.
2041 #define AUXLEN (sizeof(struct auxprm)/sizeof(int))
2042
2043
2044 struct wcsprm {
2045 // Initialization flag (see the prologue above).
2046 //--------------------------------------------------------------------------
2047 int flag; // Set to zero to force initialization.
2048
2049 // FITS header keyvalues to be provided (see the prologue above).
2050 //--------------------------------------------------------------------------
2051 int naxis; // Number of axes (pixel and coordinate).
2052 double *crpix; // CRPIXja keyvalues for each pixel axis.
2053 double *pc; // PCi_ja linear transformation matrix.
2054 double *cdelt; // CDELTia keyvalues for each coord axis.
2055 double *crval; // CRVALia keyvalues for each coord axis.
2056
2057 char (*cunit)[72]; // CUNITia keyvalues for each coord axis.
2058 char (*ctype)[72]; // CTYPEia keyvalues for each coord axis.
2059
2060 double lonpole; // LONPOLEa keyvalue.
2061 double latpole; // LATPOLEa keyvalue.
2062
2063 double restfrq; // RESTFRQa keyvalue.
2064 double restwav; // RESTWAVa keyvalue.
2065
2066 int npv; // Number of PVi_ma keywords, and the
2067 int npvmax; // number for which space was allocated.
2068 struct pvcard *pv; // PVi_ma keywords for each i and m.
2069
2070 int nps; // Number of PSi_ma keywords, and the
2071 int npsmax; // number for which space was allocated.
2072 struct pscard *ps; // PSi_ma keywords for each i and m.
2073
2074 // Alternative header keyvalues (see the prologue above).
2075 //--------------------------------------------------------------------------
2076 double *cd; // CDi_ja linear transformation matrix.
2077 double *crota; // CROTAi keyvalues for each coord axis.
2078 int altlin; // Alternative representations
2079 // Bit 0: PCi_ja is present,
2080 // Bit 1: CDi_ja is present,
2081 // Bit 2: CROTAi is present.
2082 int velref; // AIPS velocity code, VELREF.
2083
2084 // Auxiliary coordinate system information of a general nature. Not
2085 // used by WCSLIB. Refer to the prologue comments above for a brief
2086 // explanation of these values.
2087 char alt[4];
2088 int colnum;
2089 int *colax;
2090 // Auxiliary coordinate axis information.
2091 char (*cname)[72];
2092 double *crder;
2093 double *csyer;
2094 double *czphs;
2095 double *cperi;
2096
2097 char wcsname[72];
2098 // Time reference system and measurement.
2099 char timesys[72], trefpos[72], trefdir[72], plephem[72];
2100 char timeunit[72];
2101 char dateref[72];
2102 double mjdref[2];
2103 double timeoffs;
2104 // Data timestamps and durations.
2105 char dateobs[72], datebeg[72], dateavg[72], dateend[72];
2106 double mjdobs, mjdbeg, mjdavg, mjdend;
2107 double jepoch, bepoch;
2108 double tstart, tstop;
2109 double xposure, telapse;
2110 // Timing accuracy.
2111 double timsyer, timrder;
2112 double timedel, timepixr;
2113 // Spatial & celestial reference frame.
2114 double obsgeo[6];
2115 char obsorbit[72];
2116 char radesys[72];
2117 double equinox;
2118 char specsys[72];
2119 char ssysobs[72];
2120 double velosys;
2121 double zsource;
2122 char ssyssrc[72];
2123 double velangl;
2124
2125 // Additional auxiliary coordinate system information of a specialist
2126 // nature. Not used by WCSLIB. Refer to the prologue comments above.
2127 struct auxprm *aux;
2128
2129 // Coordinate lookup tables (see the prologue above).
2130 //--------------------------------------------------------------------------
2131 int ntab; // Number of separate tables.
2132 int nwtb; // Number of wtbarr structs.
2133 struct tabprm *tab; // Tabular transformation parameters.
2134 struct wtbarr *wtb; // Array of wtbarr structs.
2135
2136 //--------------------------------------------------------------------------
2137 // Information derived from the FITS header keyvalues by wcsset().
2138 //--------------------------------------------------------------------------
2139 char lngtyp[8], lattyp[8]; // Celestial axis types, e.g. RA, DEC.
2140 int lng, lat, spec; // Longitude, latitude and spectral axis
2141 // indices (0-relative).
2142 int cubeface; // True if there is a CUBEFACE axis.
2143 int *types; // Coordinate type codes for each axis.
2144
2145 struct linprm lin; // Linear transformation parameters.
2146 struct celprm cel; // Celestial transformation parameters.
2147 struct spcprm spc; // Spectral transformation parameters.
2148
2149 //--------------------------------------------------------------------------
2150 // THE REMAINDER OF THE WCSPRM STRUCT IS PRIVATE.
2151 //--------------------------------------------------------------------------
2152
2153 // Error handling, if enabled.
2154 //--------------------------------------------------------------------------
2155 struct wcserr *err;
2156
2157 // Memory management.
2158 //--------------------------------------------------------------------------
2159 int m_flag, m_naxis;
2160 double *m_crpix, *m_pc, *m_cdelt, *m_crval;
2161 char (*m_cunit)[72], (*m_ctype)[72];
2162 struct pvcard *m_pv;
2163 struct pscard *m_ps;
2164 double *m_cd, *m_crota;
2165 int *m_colax;
2166 char (*m_cname)[72];
2167 double *m_crder, *m_csyer, *m_czphs, *m_cperi;
2168 struct auxprm *m_aux;
2169 struct tabprm *m_tab;
2170 struct wtbarr *m_wtb;
2171 };
2172
2173 // Size of the wcsprm struct in int units, used by the Fortran wrappers.
2174 #define WCSLEN (sizeof(struct wcsprm)/sizeof(int))
2175
2176
2177 int wcsnpv(int n);
2178
2179 int wcsnps(int n);
2180
2181 int wcsini(int alloc, int naxis, struct wcsprm *wcs);
2182
2183 int wcsinit(int alloc, int naxis, struct wcsprm *wcs, int npvmax, int npsmax,
2184 int ndpmax);
2185
2186 int wcsauxi(int alloc, struct wcsprm *wcs);
2187
2188 int wcssub(int alloc, const struct wcsprm *wcssrc, int *nsub, int axes[],
2189 struct wcsprm *wcsdst);
2190
2191 int wcscompare(int cmp, double tol, const struct wcsprm *wcs1,
2192 const struct wcsprm *wcs2, int *equal);
2193
2194 int wcsfree(struct wcsprm *wcs);
2195
2196 int wcstrim(struct wcsprm *wcs);
2197
2198 int wcssize(const struct wcsprm *wcs, int sizes[2]);
2199
2200 int auxsize(const struct auxprm *aux, int sizes[2]);
2201
2202 int wcsprt(const struct wcsprm *wcs);
2203
2204 int wcsperr(const struct wcsprm *wcs, const char *prefix);
2205
2206 int wcsbchk(struct wcsprm *wcs, int bounds);
2207
2208 int wcsset(struct wcsprm *wcs);
2209
2210 int wcsp2s(struct wcsprm *wcs, int ncoord, int nelem, const double pixcrd[],
2211 double imgcrd[], double phi[], double theta[], double world[],
2212 int stat[]);
2213
2214 int wcss2p(struct wcsprm *wcs, int ncoord, int nelem, const double world[],
2215 double phi[], double theta[], double imgcrd[], double pixcrd[],
2216 int stat[]);
2217
2218 int wcsmix(struct wcsprm *wcs, int mixpix, int mixcel, const double vspan[],
2219 double vstep, int viter, double world[], double phi[],
2220 double theta[], double imgcrd[], double pixcrd[]);
2221
2222 int wcsccs(struct wcsprm *wcs, double lng2p1, double lat2p1, double lng1p2,
2223 const char *clng, const char *clat, const char *radesys,
2224 double equinox, const char *alt);
2225
2226 int wcssptr(struct wcsprm *wcs, int *i, char ctype[9]);
2227
2228 const char* wcslib_version(int vers[3]);
2229
2230 // Defined mainly for backwards compatibility, use wcssub() instead.
2231 #define wcscopy(alloc, wcssrc, wcsdst) wcssub(alloc, wcssrc, 0x0, 0x0, wcsdst)
2232
2233
2234 // Deprecated.
2235 #define wcsini_errmsg wcs_errmsg
2236 #define wcssub_errmsg wcs_errmsg
2237 #define wcscopy_errmsg wcs_errmsg
2238 #define wcsfree_errmsg wcs_errmsg
2239 #define wcsprt_errmsg wcs_errmsg
2240 #define wcsset_errmsg wcs_errmsg
2241 #define wcsp2s_errmsg wcs_errmsg
2242 #define wcss2p_errmsg wcs_errmsg
2243 #define wcsmix_errmsg wcs_errmsg
2244
2245 #ifdef __cplusplus
2246 #undef wtbarr
2247 }
2248 #endif
2249
2250 #endif // WCSLIB_WCS
cel.h
lin.h
spc.h
auxprm
Additional auxiliary parameters.
Definition: wcs.h:2032
auxprm::dsun_obs
double dsun_obs
Definition: wcs.h:2034
auxprm::hglt_obs
double hglt_obs
Definition: wcs.h:2037
auxprm::hgln_obs
double hgln_obs
Definition: wcs.h:2036
auxprm::crln_obs
double crln_obs
Definition: wcs.h:2035
auxprm::rsun_ref
double rsun_ref
Definition: wcs.h:2033
celprm
Celestial transformation parameters.
Definition: cel.h:423
linprm
Linear transformation parameters.
Definition: lin.h:657
pscard
Store for PSi_ma keyrecords.
Definition: wcs.h:2022
pscard::i
int i
Definition: wcs.h:2023
pscard::m
int m
Definition: wcs.h:2024
pscard::value
char value[72]
Definition: wcs.h:2025
pvcard
Store for PVi_ma keyrecords.
Definition: wcs.h:2012
pvcard::value
double value
Definition: wcs.h:2015
pvcard::i
int i
Definition: wcs.h:2013
pvcard::m
int m
Definition: wcs.h:2014
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:2044
wcsprm::timeunit
char timeunit[72]
Definition: wcs.h:2100
wcsprm::m_ps
struct pscard * m_ps
Definition: wcs.h:2163
wcsprm::timesys
char timesys[72]
Definition: wcs.h:2099
wcsprm::pv
struct pvcard * pv
Definition: wcs.h:2068
wcsprm::dateref
char dateref[72]
Definition: wcs.h:2101
wcsprm::mjdavg
double mjdavg
Definition: wcs.h:2106
wcsprm::lng
int lng
Definition: wcs.h:2140
wcsprm::czphs
double * czphs
Definition: wcs.h:2094
wcsprm::m_cname
char(* m_cname)[72]
Definition: wcs.h:2166
wcsprm::zsource
double zsource
Definition: wcs.h:2121
wcsprm::m_crder
double * m_crder
Definition: wcs.h:2167
wcsprm::npv
int npv
Definition: wcs.h:2066
wcsprm::timrder
double timrder
Definition: wcs.h:2111
wcsprm::trefpos
char trefpos[72]
Definition: wcs.h:2099
wcsprm::telapse
double telapse
Definition: wcs.h:2109
wcsprm::m_csyer
double * m_csyer
Definition: wcs.h:2167
wcsprm::tstart
double tstart
Definition: wcs.h:2108
wcsprm::csyer
double * csyer
Definition: wcs.h:2093
wcsprm::m_crpix
double * m_crpix
Definition: wcs.h:2160
wcsprm::cperi
double * cperi
Definition: wcs.h:2095
wcsprm::mjdend
double mjdend
Definition: wcs.h:2106
wcsprm::wcsname
char wcsname[72]
Definition: wcs.h:2097
wcsprm::tab
struct tabprm * tab
Definition: wcs.h:2133
wcsprm::lin
struct linprm lin
Definition: wcs.h:2145
wcsprm::pc
double * pc
Definition: wcs.h:2053
wcsprm::flag
int flag
Definition: wcs.h:2047
wcsprm::aux
struct auxprm * aux
Definition: wcs.h:2127
wcsprm::npsmax
int npsmax
Definition: wcs.h:2071
wcsprm::m_cdelt
double * m_cdelt
Definition: wcs.h:2160
wcsprm::timeoffs
double timeoffs
Definition: wcs.h:2103
wcsprm::crder
double * crder
Definition: wcs.h:2092
wcsprm::nps
int nps
Definition: wcs.h:2070
wcsprm::m_colax
int * m_colax
Definition: wcs.h:2165
wcsprm::m_crval
double * m_crval
Definition: wcs.h:2160
wcsprm::timepixr
double timepixr
Definition: wcs.h:2112
wcsprm::m_crota
double * m_crota
Definition: wcs.h:2164
wcsprm::m_cperi
double * m_cperi
Definition: wcs.h:2167
wcsprm::m_flag
int m_flag
Definition: wcs.h:2159
wcsprm::lngtyp
char lngtyp[8]
Definition: wcs.h:2139
wcsprm::restwav
double restwav
Definition: wcs.h:2064
wcsprm::latpole
double latpole
Definition: wcs.h:2061
wcsprm::m_naxis
int m_naxis
Definition: wcs.h:2159
wcsprm::radesys
char radesys[72]
Definition: wcs.h:2116
wcsprm::m_pc
double * m_pc
Definition: wcs.h:2160
wcsprm::m_pv
struct pvcard * m_pv
Definition: wcs.h:2162
wcsprm::naxis
int naxis
Definition: wcs.h:2051
wcsprm::m_czphs
double * m_czphs
Definition: wcs.h:2167
wcsprm::colax
int * colax
Definition: wcs.h:2089
wcsprm::crval
double * crval
Definition: wcs.h:2055
wcsprm::m_cd
double * m_cd
Definition: wcs.h:2164
wcsprm::tstop
double tstop
Definition: wcs.h:2108
wcsprm::obsgeo
double obsgeo[6]
Definition: wcs.h:2114
wcsprm::timsyer
double timsyer
Definition: wcs.h:2111
wcsprm::nwtb
int nwtb
Definition: wcs.h:2132
wcsprm::ssyssrc
char ssyssrc[72]
Definition: wcs.h:2122
wcsprm::equinox
double equinox
Definition: wcs.h:2117
wcsprm::altlin
int altlin
Definition: wcs.h:2078
wcsprm::wtb
struct wtbarr * wtb
Definition: wcs.h:2134
wcsprm::npvmax
int npvmax
Definition: wcs.h:2067
wcsprm::cname
char(* cname)[72]
Definition: wcs.h:2091
wcsprm::jepoch
double jepoch
Definition: wcs.h:2107
wcsprm::ntab
int ntab
Definition: wcs.h:2131
wcsprm::ssysobs
char ssysobs[72]
Definition: wcs.h:2119
wcsprm::ps
struct pscard * ps
Definition: wcs.h:2072
wcsprm::colnum
int colnum
Definition: wcs.h:2088
wcsprm::datebeg
char datebeg[72]
Definition: wcs.h:2105
wcsprm::velangl
double velangl
Definition: wcs.h:2123
wcsprm::mjdbeg
double mjdbeg
Definition: wcs.h:2106
wcsprm::cunit
char(* cunit)[72]
Definition: wcs.h:2057
wcsprm::bepoch
double bepoch
Definition: wcs.h:2107
wcsprm::mjdref
double mjdref[2]
Definition: wcs.h:2102
wcsprm::trefdir
char trefdir[72]
Definition: wcs.h:2099
wcsprm::plephem
char plephem[72]
Definition: wcs.h:2099
wcsprm::dateobs
char dateobs[72]
Definition: wcs.h:2105
wcsprm::crpix
double * crpix
Definition: wcs.h:2052
wcsprm::types
int * types
Definition: wcs.h:2143
wcsprm::lat
int lat
Definition: wcs.h:2140
wcsprm::spec
int spec
Definition: wcs.h:2140
wcsprm::specsys
char specsys[72]
Definition: wcs.h:2118
wcsprm::mjdobs
double mjdobs
Definition: wcs.h:2106
wcsprm::xposure
double xposure
Definition: wcs.h:2109
wcsprm::velref
int velref
Definition: wcs.h:2082
wcsprm::cel
struct celprm cel
Definition: wcs.h:2146
wcsprm::m_wtb
struct wtbarr * m_wtb
Definition: wcs.h:2170
wcsprm::dateend
char dateend[72]
Definition: wcs.h:2105
wcsprm::m_aux
struct auxprm * m_aux
Definition: wcs.h:2168
wcsprm::restfrq
double restfrq
Definition: wcs.h:2063
wcsprm::cdelt
double * cdelt
Definition: wcs.h:2054
wcsprm::cubeface
int cubeface
Definition: wcs.h:2142
wcsprm::m_tab
struct tabprm * m_tab
Definition: wcs.h:2169
wcsprm::obsorbit
char obsorbit[72]
Definition: wcs.h:2115
wcsprm::ctype
char(* ctype)[72]
Definition: wcs.h:2058
wcsprm::lattyp
char lattyp[8]
Definition: wcs.h:2139
wcsprm::dateavg
char dateavg[72]
Definition: wcs.h:2105
wcsprm::alt
char alt[4]
Definition: wcs.h:2087
wcsprm::spc
struct spcprm spc
Definition: wcs.h:2147
wcsprm::timedel
double timedel
Definition: wcs.h:2112
wcsprm::crota
double * crota
Definition: wcs.h:2077
wcsprm::m_cunit
char(* m_cunit)[72]
Definition: wcs.h:2161
wcsprm::velosys
double velosys
Definition: wcs.h:2120
wcsprm::err
struct wcserr * err
Definition: wcs.h:2155
wcsprm::lonpole
double lonpole
Definition: wcs.h:2060
wcsprm::cd
double * cd
Definition: wcs.h:2076
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:1986
WCSERR_BAD_WORLD
@ WCSERR_BAD_WORLD
Definition: wcs.h:2000
WCSERR_BAD_PIX
@ WCSERR_BAD_PIX
Definition: wcs.h:1998
WCSERR_SINGULAR_MTX
@ WCSERR_SINGULAR_MTX
Definition: wcs.h:1990
WCSERR_NON_SEPARABLE
@ WCSERR_NON_SEPARABLE
Definition: wcs.h:2006
WCSERR_BAD_CTYPE
@ WCSERR_BAD_CTYPE
Definition: wcs.h:1991
WCSERR_MEMORY
@ WCSERR_MEMORY
Definition: wcs.h:1989
WCSERR_BAD_WORLD_COORD
@ WCSERR_BAD_WORLD_COORD
Definition: wcs.h:2002
WCSERR_BAD_COORD_TRANS
@ WCSERR_BAD_COORD_TRANS
Definition: wcs.h:1994
WCSERR_NO_SOLUTION
@ WCSERR_NO_SOLUTION
Definition: wcs.h:2003
WCSERR_BAD_SUBIMAGE
@ WCSERR_BAD_SUBIMAGE
Definition: wcs.h:2005
WCSERR_SUCCESS
@ WCSERR_SUCCESS
Definition: wcs.h:1987
WCSERR_UNSET
@ WCSERR_UNSET
Definition: wcs.h:2007
WCSERR_NULL_POINTER
@ WCSERR_NULL_POINTER
Definition: wcs.h:1988
WCSERR_ILL_COORD_TRANS
@ WCSERR_ILL_COORD_TRANS
Definition: wcs.h:1996
WCSERR_BAD_PARAM
@ WCSERR_BAD_PARAM
Definition: wcs.h:1993
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.
wcslib_version
const char * wcslib_version(int vers[3])
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.
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.
wcs_errmsg
const char * wcs_errmsg[]
Status return messages.
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.
wcsmix
int wcsmix(struct wcsprm *wcs, int mixpix, int mixcel, const double vspan[], double vstep, int viter, double world[], double phi[], double theta[], double imgcrd[], double pixcrd[])
Hybrid coordinate transformation.