WCSLIB: wcs.h Source File

WCSLIB 7.3.1

wcs.h
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1 /*============================================================================
2 WCSLIB 7.3 - an implementation of the FITS WCS standard.
3 Copyright (C) 1995-2020, 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 Direct correspondence concerning WCSLIB to mark@calabretta.id.au
21
22 Author: Mark Calabretta, Australia Telescope National Facility, CSIRO.
23 http://www.atnf.csiro.au/people/Mark.Calabretta
24 $Id: wcs.h,v 7.3.1.2 2020/08/17 12:10:44 mcalabre Exp mcalabre $
25 *=============================================================================
26 *
27 * WCSLIB 7.3 - C routines that implement the FITS World Coordinate System
28 * (WCS) standard. Refer to the README file provided with WCSLIB for an
29 * overview of the library.
30 *
31 *
32 * Summary of the wcs routines
33 * ---------------------------
34 * Routines in this suite implement the FITS World Coordinate System (WCS)
35 * standard which defines methods to be used for computing world coordinates
36 * from image pixel coordinates, and vice versa. The standard, and proposed
37 * extensions for handling distortions, are described in
38 *
39 = "Representations of world coordinates in FITS",
40 = Greisen, E.W., & Calabretta, M.R. 2002, A&A, 395, 1061 (WCS Paper I)
41 =
42 = "Representations of celestial coordinates in FITS",
43 = Calabretta, M.R., & Greisen, E.W. 2002, A&A, 395, 1077 (WCS Paper II)
44 =
45 = "Representations of spectral coordinates in FITS",
46 = Greisen, E.W., Calabretta, M.R., Valdes, F.G., & Allen, S.L.
47 = 2006, A&A, 446, 747 (WCS Paper III)
48 =
49 = "Representations of distortions in FITS world coordinate systems",
50 = Calabretta, M.R. et al. (WCS Paper IV, draft dated 2004/04/22),
51 = available from http://www.atnf.csiro.au/people/Mark.Calabretta
52 =
53 = "Mapping on the HEALPix grid",
54 = Calabretta, M.R., & Roukema, B.F. 2007, MNRAS, 381, 865 (WCS Paper V)
55 =
56 = "Representing the 'Butterfly' Projection in FITS -- Projection Code XPH",
57 = Calabretta, M.R., & Lowe, S.R. 2013, PASA, 30, e050 (WCS Paper VI)
58 =
59 = "Representations of time coordinates in FITS -
60 = Time and relative dimension in space",
61 = Rots, A.H., Bunclark, P.S., Calabretta, M.R., Allen, S.L.,
62 = Manchester, R.N., & Thompson, W.T. 2015, A&A, 574, A36 (WCS Paper VII)
63 *
64 * These routines are based on the wcsprm struct which contains all information
65 * needed for the computations. The struct contains some members that must be
66 * set by the user, and others that are maintained by these routines, somewhat
67 * like a C++ class but with no encapsulation.
68 *
69 * wcsnpv(), wcsnps(), wcsini(), wcsinit(), wcssub(), and wcsfree() are
70 * provided to manage the wcsprm struct and another, wcsprt(), prints its
71 * contents. Refer to the description of the wcsprm struct for an explanation
72 * of the anticipated usage of these routines. wcscopy(), which does a deep
73 * copy of one wcsprm struct to another, is defined as a preprocessor macro
74 * function that invokes wcssub().
75 *
76 * wcsperr() prints the error message(s) (if any) stored in a wcsprm struct,
77 * and the linprm, celprm, prjprm, spcprm, and tabprm structs that it contains.
78 *
79 * A setup routine, wcsset(), computes intermediate values in the wcsprm struct
80 * from parameters in it that were supplied by the user. The struct always
81 * needs to be set up by wcsset() but this need not be called explicitly -
82 * refer to the explanation of wcsprm::flag.
83 *
84 * wcsp2s() and wcss2p() implement the WCS world coordinate transformations.
85 * In fact, they are high level driver routines for the WCS linear,
86 * logarithmic, celestial, spectral and tabular transformation routines
87 * described in lin.h, log.h, cel.h, spc.h and tab.h.
88 *
89 * Given either the celestial longitude or latitude plus an element of the
90 * pixel coordinate a hybrid routine, wcsmix(), iteratively solves for the
91 * unknown elements.
92 *
93 * wcssptr() translates the spectral axis in a wcsprm struct. For example, a
94 * 'FREQ' axis may be translated into 'ZOPT-F2W' and vice versa.
95 *
96 * wcslib_version() returns the WCSLIB version number.
97 *
98 * Quadcube projections:
99 * ---------------------
100 * The quadcube projections (TSC, CSC, QSC) may be represented in FITS in
101 * either of two ways:
102 *
103 * a: The six faces may be laid out in one plane and numbered as follows:
104 *
105 = 0
106 =
107 = 4 3 2 1 4 3 2
108 =
109 = 5
110 *
111 * Faces 2, 3 and 4 may appear on one side or the other (or both). The
112 * world-to-pixel routines map faces 2, 3 and 4 to the left but the
113 * pixel-to-world routines accept them on either side.
114 *
115 * b: The "COBE" convention in which the six faces are stored in a
116 * three-dimensional structure using a CUBEFACE axis indexed from
117 * 0 to 5 as above.
118 *
119 * These routines support both methods; wcsset() determines which is being
120 * used by the presence or absence of a CUBEFACE axis in ctype[]. wcsp2s()
121 * and wcss2p() translate the CUBEFACE axis representation to the single
122 * plane representation understood by the lower-level WCSLIB projection
123 * routines.
124 *
125 *
126 * wcsnpv() - Memory allocation for PVi_ma
127 * ---------------------------------------
128 * wcsnpv() sets or gets the value of NPVMAX (default 64). This global
129 * variable controls the number of pvcard structs, for holding PVi_ma
130 * keyvalues, that wcsini() should allocate space for. It is also used by
131 * wcsinit() as the default value of npvmax.
132 *
133 * PLEASE NOTE: This function is not thread-safe.
134 *
135 * Given:
136 * n int Value of NPVMAX; ignored if < 0. Use a value less
137 * than zero to get the current value.
138 *
139 * Function return value:
140 * int Current value of NPVMAX.
141 *
142 *
143 * wcsnps() - Memory allocation for PSi_ma
144 * ---------------------------------------
145 * wcsnps() sets or gets the value of NPSMAX (default 8). This global variable
146 * controls the number of pscard structs, for holding PSi_ma keyvalues, that
147 * wcsini() should allocate space for. It is also used by wcsinit() as the
148 * default value of npsmax.
149 *
150 * PLEASE NOTE: This function is not thread-safe.
151 *
152 * Given:
153 * n int Value of NPSMAX; ignored if < 0. Use a value less
154 * than zero to get the current value.
155 *
156 * Function return value:
157 * int Current value of NPSMAX.
158 *
159 *
160 * wcsini() - Default constructor for the wcsprm struct
161 * ----------------------------------------------------
162 * wcsini() is a thin wrapper on wcsinit(). It invokes it with npvmax,
163 * npsmax, and ndpmax set to -1 which causes it to use the values of the
164 * global variables NDPMAX, NPSMAX, and NDPMAX. It is thereby potentially
165 * thread-unsafe if these variables are altered dynamically via wcsnpv(),
166 * wcsnps(), and disndp(). Use wcsinit() for a thread-safe alternative in
167 * this case.
168 *
169 *
170 * wcsinit() - Default constructor for the wcsprm struct
171 * -----------------------------------------------------
172 * wcsinit() optionally allocates memory for arrays in a wcsprm struct and sets
173 * all members of the struct to default values.
174 *
175 * PLEASE NOTE: every wcsprm struct should be initialized by wcsinit(),
176 * possibly repeatedly. On the first invokation, and only the first
177 * invokation, wcsprm::flag must be set to -1 to initialize memory management,
178 * regardless of whether wcsinit() will actually be used to allocate memory.
179 *
180 * Given:
181 * alloc int If true, allocate memory unconditionally for the
182 * crpix, etc. arrays. Please note that memory is never
183 * allocated by wcsinit() for the auxprm, tabprm, nor
184 * wtbarr structs.
185 *
186 * If false, it is assumed that pointers to these arrays
187 * have been set by the user except if they are null
188 * pointers in which case memory will be allocated for
189 * them regardless. (In other words, setting alloc true
190 * saves having to initalize these pointers to zero.)
191 *
192 * naxis int The number of world coordinate axes. This is used to
193 * determine the length of the various wcsprm vectors and
194 * matrices and therefore the amount of memory to
195 * allocate for them.
196 *
197 * Given and returned:
198 * wcs struct wcsprm*
199 * Coordinate transformation parameters.
200 *
201 * Note that, in order to initialize memory management,
202 * wcsprm::flag should be set to -1 when wcs is
203 * initialized for the first time (memory leaks may
204 * result if it had already been initialized).
205 *
206 * Given:
207 * npvmax int The number of PVi_ma keywords to allocate space for.
208 * If set to -1, the value of the global variable NPVMAX
209 * will be used. This is potentially thread-unsafe if
210 * wcsnpv() is being used dynamically to alter its value.
211 *
212 * npsmax int The number of PSi_ma keywords to allocate space for.
213 * If set to -1, the value of the global variable NPSMAX
214 * will be used. This is potentially thread-unsafe if
215 * wcsnps() is being used dynamically to alter its value.
216 *
217 * ndpmax int The number of DPja or DQia keywords to allocate space
218 * for. If set to -1, the value of the global variable
219 * NDPMAX will be used. This is potentially
220 * thread-unsafe if disndp() is being used dynamically to
221 * alter its value.
222 *
223 * Function return value:
224 * int Status return value:
225 * 0: Success.
226 * 1: Null wcsprm pointer passed.
227 * 2: Memory allocation failed.
228 *
229 * For returns > 1, a detailed error message is set in
230 * wcsprm::err if enabled, see wcserr_enable().
231 *
232 *
233 * wcsauxi() - Default constructor for the auxprm struct
234 * -----------------------------------------------------
235 * wcsauxi() optionally allocates memory for an auxprm struct, attaches it to
236 * wcsprm, and sets all members of the struct to default values.
237 *
238 * Given:
239 * alloc int If true, allocate memory unconditionally for the
240 * auxprm struct.
241 *
242 * If false, it is assumed that wcsprm::aux has already
243 * been set to point to an auxprm struct, in which case
244 * the user is responsible for managing that memory.
245 * However, if wcsprm::aux is a null pointer, memory will
246 * be allocated regardless. (In other words, setting
247 * alloc true saves having to initalize the pointer to
248 * zero.)
249 *
250 * Given and returned:
251 * wcs struct wcsprm*
252 * Coordinate transformation parameters.
253 *
254 * Function return value:
255 * int Status return value:
256 * 0: Success.
257 * 1: Null wcsprm pointer passed.
258 * 2: Memory allocation failed.
259 *
260 *
261 * wcssub() - Subimage extraction routine for the wcsprm struct
262 * ------------------------------------------------------------
263 * wcssub() extracts the coordinate description for a subimage from a wcsprm
264 * struct. It does a deep copy, using wcsinit() to allocate memory for its
265 * arrays if required. Only the "information to be provided" part of the
266 * struct is extracted. Consequently, wcsset() need not have been, and won't
267 * be invoked on the struct from which the subimage is extracted. A call to
268 * wcsset() is required to set up the subimage struct.
269 *
270 * The world coordinate system of the subimage must be separable in the sense
271 * that the world coordinates at any point in the subimage must depend only on
272 * the pixel coordinates of the axes extracted. In practice, this means that
273 * the linear transformation matrix of the original image must not contain
274 * non-zero off-diagonal terms that associate any of the subimage axes with any
275 * of the non-subimage axes. Likewise, if any distortions are associated with
276 * the subimage axes, they must not depend on any of the axes that are not
277 * being extracted.
278 *
279 * Note that while the required elements of the tabprm array are extracted, the
280 * wtbarr array is not. (Thus it is not appropriate to call wcssub() after
281 * wcstab() but before filling the tabprm structs - refer to wcshdr.h.)
282 *
283 * wcssub() can also add axes to a wcsprm struct. The new axes will be created
284 * using the defaults set by wcsinit() which produce a simple, unnamed, linear
285 * axis with world coordinate equal to the pixel coordinate. These default
286 * values can be changed afterwards, before invoking wcsset().
287 *
288 * Given:
289 * alloc int If true, allocate memory for the crpix, etc. arrays in
290 * the destination. Otherwise, it is assumed that
291 * pointers to these arrays have been set by the user
292 * except if they are null pointers in which case memory
293 * will be allocated for them regardless.
294 *
295 * wcssrc const struct wcsprm*
296 * Struct to extract from.
297 *
298 * Given and returned:
299 * nsub int*
300 * axes int[] Vector of length *nsub containing the image axis
301 * numbers (1-relative) to extract. Order is
302 * significant; axes[0] is the axis number of the input
303 * image that corresponds to the first axis in the
304 * subimage, etc.
305 *
306 * Use an axis number of 0 to create a new axis using
307 * the defaults set by wcsinit(). They can be changed
308 * later.
309 *
310 * nsub (the pointer) may be set to zero, and so also may
311 * *nsub, which is interpreted to mean all axes in the
312 * input image; the number of axes will be returned if
313 * nsub != 0x0. axes itself (the pointer) may be set to
314 * zero to indicate the first *nsub axes in their
315 * original order.
316 *
317 * Set both nsub (or *nsub) and axes to zero to do a deep
318 * copy of one wcsprm struct to another.
319 *
320 * Subimage extraction by coordinate axis type may be
321 * done by setting the elements of axes[] to the
322 * following special preprocessor macro values:
323 *
324 * WCSSUB_LONGITUDE: Celestial longitude.
325 * WCSSUB_LATITUDE: Celestial latitude.
326 * WCSSUB_CUBEFACE: Quadcube CUBEFACE axis.
327 * WCSSUB_SPECTRAL: Spectral axis.
328 * WCSSUB_STOKES: Stokes axis.
329 *
330 * Refer to the notes (below) for further usage examples.
331 *
332 * On return, *nsub will be set to the number of axes in
333 * the subimage; this may be zero if there were no axes
334 * of the required type(s) (in which case no memory will
335 * be allocated). axes[] will contain the axis numbers
336 * that were extracted, or 0 for newly created axes. The
337 * vector length must be sufficient to contain all axis
338 * numbers. No checks are performed to verify that the
339 * coordinate axes are consistent, this is done by
340 * wcsset().
341 *
342 * wcsdst struct wcsprm*
343 * Struct describing the subimage. wcsprm::flag should
344 * be set to -1 if wcsdst was not previously initialized
345 * (memory leaks may result if it was previously
346 * initialized).
347 *
348 * Function return value:
349 * int Status return value:
350 * 0: Success.
351 * 1: Null wcsprm pointer passed.
352 * 2: Memory allocation failed.
353 * 12: Invalid subimage specification.
354 * 13: Non-separable subimage coordinate system.
355 *
356 * For returns > 1, a detailed error message is set in
357 * wcsprm::err if enabled, see wcserr_enable().
358 *
359 * Notes:
360 * Combinations of subimage axes of particular types may be extracted in the
361 * same order as they occur in the input image by combining preprocessor
362 * codes, for example
363 *
364 = *nsub = 1;
365 = axes[0] = WCSSUB_LONGITUDE | WCSSUB_LATITUDE | WCSSUB_SPECTRAL;
366 *
367 * would extract the longitude, latitude, and spectral axes in the same order
368 * as the input image. If one of each were present, *nsub = 3 would be
369 * returned.
370 *
371 * For convenience, WCSSUB_CELESTIAL is defined as the combination
372 * WCSSUB_LONGITUDE | WCSSUB_LATITUDE | WCSSUB_CUBEFACE.
373 *
374 * The codes may also be negated to extract all but the types specified, for
375 * example
376 *
377 = *nsub = 4;
378 = axes[0] = WCSSUB_LONGITUDE;
379 = axes[1] = WCSSUB_LATITUDE;
380 = axes[2] = WCSSUB_CUBEFACE;
381 = axes[3] = -(WCSSUB_SPECTRAL | WCSSUB_STOKES);
382 *
383 * The last of these specifies all axis types other than spectral or Stokes.
384 * Extraction is done in the order specified by axes[] a longitude axis (if
385 * present) would be extracted first (via axes[0]) and not subsequently (via
386 * axes[3]). Likewise for the latitude and cubeface axes in this example.
387 *
388 * From the foregoing, it is apparent that the value of *nsub returned may be
389 * less than or greater than that given. However, it will never exceed the
390 * number of axes in the input image (plus the number of newly-created axes
391 * if any were specified on input).
392 *
393 *
394 * wcscompare() - Compare two wcsprm structs for equality
395 * ------------------------------------------------------
396 * wcscompare() compares two wcsprm structs for equality.
397 *
398 * Given:
399 * cmp int A bit field controlling the strictness of the
400 * comparison. When 0, all fields must be identical.
401 *
402 * The following constants may be or'ed together to
403 * relax the comparison:
404 * WCSCOMPARE_ANCILLARY: Ignore ancillary keywords
405 * that don't change the WCS transformation, such
406 * as DATE-OBS or EQUINOX.
407 * WCSCOMPARE_TILING: Ignore integral differences in
408 * CRPIXja. This is the 'tiling' condition, where
409 * two WCSes cover different regions of the same
410 * map projection and align on the same map grid.
411 * WCSCOMPARE_CRPIX: Ignore any differences at all in
412 * CRPIXja. The two WCSes cover different regions
413 * of the same map projection but may not align on
414 * the same map grid. Overrides WCSCOMPARE_TILING.
415 *
416 * tol double Tolerance for comparison of floating-point values.
417 * For example, for tol == 1e-6, all floating-point
418 * values in the structs must be equal to the first 6
419 * decimal places. A value of 0 implies exact equality.
420 *
421 * wcs1 const struct wcsprm*
422 * The first wcsprm struct to compare.
423 *
424 * wcs2 const struct wcsprm*
425 * The second wcsprm struct to compare.
426 *
427 * Returned:
428 * equal int* Non-zero when the given structs are equal.
429 *
430 * Function return value:
431 * int Status return value:
432 * 0: Success.
433 * 1: Null pointer passed.
434 *
435 *
436 * wcscopy() macro - Copy routine for the wcsprm struct
437 * ----------------------------------------------------
438 * wcscopy() does a deep copy of one wcsprm struct to another. As of
439 * WCSLIB 3.6, it is implemented as a preprocessor macro that invokes
440 * wcssub() with the nsub and axes pointers both set to zero.
441 *
442 *
443 * wcsfree() - Destructor for the wcsprm struct
444 * --------------------------------------------
445 * wcsfree() frees memory allocated for the wcsprm arrays by wcsinit() and/or
446 * wcsset(). wcsinit() records the memory it allocates and wcsfree() will only
447 * attempt to free this.
448 *
449 * PLEASE NOTE: wcsfree() must not be invoked on a wcsprm struct that was not
450 * initialized by wcsinit().
451 *
452 * Returned:
453 * wcs struct wcsprm*
454 * Coordinate transformation parameters.
455 *
456 * Function return value:
457 * int Status return value:
458 * 0: Success.
459 * 1: Null wcsprm pointer passed.
460 *
461 *
462 * wcsprt() - Print routine for the wcsprm struct
463 * ----------------------------------------------
464 * wcsprt() prints the contents of a wcsprm struct using wcsprintf(). Mainly
465 * intended for diagnostic purposes.
466 *
467 * Given:
468 * wcs const struct wcsprm*
469 * Coordinate transformation parameters.
470 *
471 * Function return value:
472 * int Status return value:
473 * 0: Success.
474 * 1: Null wcsprm pointer passed.
475 *
476 *
477 * wcsperr() - Print error messages from a wcsprm struct
478 * -----------------------------------------------------
479 * wcsperr() prints the error message(s), if any, stored in a wcsprm struct,
480 * and the linprm, celprm, prjprm, spcprm, and tabprm structs that it contains.
481 * If there are no errors then nothing is printed. It uses wcserr_prt(), q.v.
482 *
483 * Given:
484 * wcs const struct wcsprm*
485 * Coordinate transformation parameters.
486 *
487 * prefix const char *
488 * If non-NULL, each output line will be prefixed with
489 * this string.
490 *
491 * Function return value:
492 * int Status return value:
493 * 0: Success.
494 * 1: Null wcsprm pointer passed.
495 *
496 *
497 * wcsbchk() - Enable/disable bounds checking
498 * ------------------------------------------
499 * wcsbchk() is used to control bounds checking in the projection routines.
500 * Note that wcsset() always enables bounds checking. wcsbchk() will invoke
501 * wcsset() on the wcsprm struct beforehand if necessary.
502 *
503 * Given and returned:
504 * wcs struct wcsprm*
505 * Coordinate transformation parameters.
506 *
507 * Given:
508 * bounds int If bounds&1 then enable strict bounds checking for the
509 * spherical-to-Cartesian (s2x) transformation for the
510 * AZP, SZP, TAN, SIN, ZPN, and COP projections.
511 *
512 * If bounds&2 then enable strict bounds checking for the
513 * Cartesian-to-spherical (x2s) transformation for the
514 * HPX and XPH projections.
515 *
516 * If bounds&4 then enable bounds checking on the native
517 * coordinates returned by the Cartesian-to-spherical
518 * (x2s) transformations using prjchk().
519 *
520 * Zero it to disable all checking.
521 *
522 * Function return value:
523 * int Status return value:
524 * 0: Success.
525 * 1: Null wcsprm pointer passed.
526 *
527 *
528 * wcsset() - Setup routine for the wcsprm struct
529 * ----------------------------------------------
530 * wcsset() sets up a wcsprm struct according to information supplied within
531 * it (refer to the description of the wcsprm struct).
532 *
533 * wcsset() recognizes the NCP projection and converts it to the equivalent SIN
534 * projection and likewise translates GLS into SFL. It also translates the
535 * AIPS spectral types ('FREQ-LSR', 'FELO-HEL', etc.), possibly changing the
536 * input header keywords wcsprm::ctype and/or wcsprm::specsys if necessary.
537 *
538 * Note that this routine need not be called directly; it will be invoked by
539 * wcsp2s() and wcss2p() if the wcsprm::flag is anything other than a
540 * predefined magic value.
541 *
542 * Given and returned:
543 * wcs struct wcsprm*
544 * Coordinate transformation parameters.
545 *
546 * Function return value:
547 * int Status return value:
548 * 0: Success.
549 * 1: Null wcsprm pointer passed.
550 * 2: Memory allocation failed.
551 * 3: Linear transformation matrix is singular.
552 * 4: Inconsistent or unrecognized coordinate axis
553 * types.
554 * 5: Invalid parameter value.
555 * 6: Invalid coordinate transformation parameters.
556 * 7: Ill-conditioned coordinate transformation
557 * parameters.
558 *
559 * For returns > 1, a detailed error message is set in
560 * wcsprm::err if enabled, see wcserr_enable().
561 *
562 * Notes:
563 * wcsset() always enables strict bounds checking in the projection routines
564 * (via a call to prjini()). Use wcsbchk() to modify bounds-checking after
565 * wcsset() is invoked.
566 *
567 *
568 * wcsp2s() - Pixel-to-world transformation
569 * ----------------------------------------
570 * wcsp2s() transforms pixel coordinates to world coordinates.
571 *
572 * Given and returned:
573 * wcs struct wcsprm*
574 * Coordinate transformation parameters.
575 *
576 * Given:
577 * ncoord,
578 * nelem int The number of coordinates, each of vector length
579 * nelem but containing wcs.naxis coordinate elements.
580 * Thus nelem must equal or exceed the value of the
581 * NAXIS keyword unless ncoord == 1, in which case nelem
582 * is not used.
583 *
584 * pixcrd const double[ncoord][nelem]
585 * Array of pixel coordinates.
586 *
587 * Returned:
588 * imgcrd double[ncoord][nelem]
589 * Array of intermediate world coordinates. For
590 * celestial axes, imgcrd[][wcs.lng] and
591 * imgcrd[][wcs.lat] are the projected x-, and
592 * y-coordinates in pseudo "degrees". For spectral
593 * axes, imgcrd[][wcs.spec] is the intermediate spectral
594 * coordinate, in SI units.
595 *
596 * phi,theta double[ncoord]
597 * Longitude and latitude in the native coordinate system
598 * of the projection [deg].
599 *
600 * world double[ncoord][nelem]
601 * Array of world coordinates. For celestial axes,
602 * world[][wcs.lng] and world[][wcs.lat] are the
603 * celestial longitude and latitude [deg]. For
604 * spectral axes, imgcrd[][wcs.spec] is the intermediate
605 * spectral coordinate, in SI units.
606 *
607 * stat int[ncoord]
608 * Status return value for each coordinate:
609 * 0: Success.
610 * 1+: A bit mask indicating invalid pixel coordinate
611 * element(s).
612 *
613 * Function return value:
614 * int Status return value:
615 * 0: Success.
616 * 1: Null wcsprm pointer passed.
617 * 2: Memory allocation failed.
618 * 3: Linear transformation matrix is singular.
619 * 4: Inconsistent or unrecognized coordinate axis
620 * types.
621 * 5: Invalid parameter value.
622 * 6: Invalid coordinate transformation parameters.
623 * 7: Ill-conditioned coordinate transformation
624 * parameters.
625 * 8: One or more of the pixel coordinates were
626 * invalid, as indicated by the stat vector.
627 *
628 * For returns > 1, a detailed error message is set in
629 * wcsprm::err if enabled, see wcserr_enable().
630 *
631 *
632 * wcss2p() - World-to-pixel transformation
633 * ----------------------------------------
634 * wcss2p() transforms world coordinates to pixel coordinates.
635 *
636 * Given and returned:
637 * wcs struct wcsprm*
638 * Coordinate transformation parameters.
639 *
640 * Given:
641 * ncoord,
642 * nelem int The number of coordinates, each of vector length nelem
643 * but containing wcs.naxis coordinate elements. Thus
644 * nelem must equal or exceed the value of the NAXIS
645 * keyword unless ncoord == 1, in which case nelem is not
646 * used.
647 *
648 * world const double[ncoord][nelem]
649 * Array of world coordinates. For celestial axes,
650 * world[][wcs.lng] and world[][wcs.lat] are the
651 * celestial longitude and latitude [deg]. For spectral
652 * axes, world[][wcs.spec] is the spectral coordinate, in
653 * SI units.
654 *
655 * Returned:
656 * phi,theta double[ncoord]
657 * Longitude and latitude in the native coordinate
658 * system of the projection [deg].
659 *
660 * imgcrd double[ncoord][nelem]
661 * Array of intermediate world coordinates. For
662 * celestial axes, imgcrd[][wcs.lng] and
663 * imgcrd[][wcs.lat] are the projected x-, and
664 * y-coordinates in pseudo "degrees". For quadcube
665 * projections with a CUBEFACE axis the face number is
666 * also returned in imgcrd[][wcs.cubeface]. For
667 * spectral axes, imgcrd[][wcs.spec] is the intermediate
668 * spectral coordinate, in SI units.
669 *
670 * pixcrd double[ncoord][nelem]
671 * Array of pixel coordinates.
672 *
673 * stat int[ncoord]
674 * Status return value for each coordinate:
675 * 0: Success.
676 * 1+: A bit mask indicating invalid world coordinate
677 * element(s).
678 *
679 * Function return value:
680 * int Status return value:
681 * 0: Success.
682 * 1: Null wcsprm pointer passed.
683 * 2: Memory allocation failed.
684 * 3: Linear transformation matrix is singular.
685 * 4: Inconsistent or unrecognized coordinate axis
686 * types.
687 * 5: Invalid parameter value.
688 * 6: Invalid coordinate transformation parameters.
689 * 7: Ill-conditioned coordinate transformation
690 * parameters.
691 * 9: One or more of the world coordinates were
692 * invalid, as indicated by the stat vector.
693 *
694 * For returns > 1, a detailed error message is set in
695 * wcsprm::err if enabled, see wcserr_enable().
696 *
697 *
698 * wcsmix() - Hybrid coordinate transformation
699 * -------------------------------------------
700 * wcsmix(), given either the celestial longitude or latitude plus an element
701 * of the pixel coordinate, solves for the remaining elements by iterating on
702 * the unknown celestial coordinate element using wcss2p(). Refer also to the
703 * notes below.
704 *
705 * Given and returned:
706 * wcs struct wcsprm*
707 * Indices for the celestial coordinates obtained
708 * by parsing the wcsprm::ctype[].
709 *
710 * Given:
711 * mixpix int Which element of the pixel coordinate is given.
712 *
713 * mixcel int Which element of the celestial coordinate is given:
714 * 1: Celestial longitude is given in
715 * world[wcs.lng], latitude returned in
716 * world[wcs.lat].
717 * 2: Celestial latitude is given in
718 * world[wcs.lat], longitude returned in
719 * world[wcs.lng].
720 *
721 * vspan const double[2]
722 * Solution interval for the celestial coordinate [deg].
723 * The ordering of the two limits is irrelevant.
724 * Longitude ranges may be specified with any convenient
725 * normalization, for example [-120,+120] is the same as
726 * [240,480], except that the solution will be returned
727 * with the same normalization, i.e. lie within the
728 * interval specified.
729 *
730 * vstep const double
731 * Step size for solution search [deg]. If zero, a
732 * sensible, although perhaps non-optimal default will be
733 * used.
734 *
735 * viter int If a solution is not found then the step size will be
736 * halved and the search recommenced. viter controls how
737 * many times the step size is halved. The allowed range
738 * is 5 - 10.
739 *
740 * Given and returned:
741 * world double[naxis]
742 * World coordinate elements. world[wcs.lng] and
743 * world[wcs.lat] are the celestial longitude and
744 * latitude [deg]. Which is given and which returned
745 * depends on the value of mixcel. All other elements
746 * are given.
747 *
748 * Returned:
749 * phi,theta double[naxis]
750 * Longitude and latitude in the native coordinate
751 * system of the projection [deg].
752 *
753 * imgcrd double[naxis]
754 * Image coordinate elements. imgcrd[wcs.lng] and
755 * imgcrd[wcs.lat] are the projected x-, and
756 * y-coordinates in pseudo "degrees".
757 *
758 * Given and returned:
759 * pixcrd double[naxis]
760 * Pixel coordinate. The element indicated by mixpix is
761 * given and the remaining elements are returned.
762 *
763 * Function return value:
764 * int Status return value:
765 * 0: Success.
766 * 1: Null wcsprm pointer passed.
767 * 2: Memory allocation failed.
768 * 3: Linear transformation matrix is singular.
769 * 4: Inconsistent or unrecognized coordinate axis
770 * types.
771 * 5: Invalid parameter value.
772 * 6: Invalid coordinate transformation parameters.
773 * 7: Ill-conditioned coordinate transformation
774 * parameters.
775 * 10: Invalid world coordinate.
776 * 11: No solution found in the specified interval.
777 *
778 * For returns > 1, a detailed error message is set in
779 * wcsprm::err if enabled, see wcserr_enable().
780 *
781 * Notes:
782 * Initially the specified solution interval is checked to see if it's a
783 * "crossing" interval. If it isn't, a search is made for a crossing
784 * solution by iterating on the unknown celestial coordinate starting at the
785 * upper limit of the solution interval and decrementing by the specified
786 * step size. A crossing is indicated if the trial value of the pixel
787 * coordinate steps through the value specified. If a crossing interval is
788 * found then the solution is determined by a modified form of "regula falsi"
789 * division of the crossing interval. If no crossing interval was found
790 * within the specified solution interval then a search is made for a
791 * "non-crossing" solution as may arise from a point of tangency. The
792 * process is complicated by having to make allowance for the discontinuities
793 * that occur in all map projections.
794 *
795 * Once one solution has been determined others may be found by subsequent
796 * invokations of wcsmix() with suitably restricted solution intervals.
797 *
798 * Note the circumstance that arises when the solution point lies at a native
799 * pole of a projection in which the pole is represented as a finite curve,
800 * for example the zenithals and conics. In such cases two or more valid
801 * solutions may exist but wcsmix() only ever returns one.
802 *
803 * Because of its generality wcsmix() is very compute-intensive. For
804 * compute-limited applications more efficient special-case solvers could be
805 * written for simple projections, for example non-oblique cylindrical
806 * projections.
807 *
808 *
809 * wcssptr() - Spectral axis translation
810 * -------------------------------------
811 * wcssptr() translates the spectral axis in a wcsprm struct. For example, a
812 * 'FREQ' axis may be translated into 'ZOPT-F2W' and vice versa.
813 *
814 * Given and returned:
815 * wcs struct wcsprm*
816 * Coordinate transformation parameters.
817 *
818 * i int* Index of the spectral axis (0-relative). If given < 0
819 * it will be set to the first spectral axis identified
820 * from the ctype[] keyvalues in the wcsprm struct.
821 *
822 * ctype char[9] Desired spectral CTYPEia. Wildcarding may be used as
823 * for the ctypeS2 argument to spctrn() as described in
824 * the prologue of spc.h, i.e. if the final three
825 * characters are specified as "???", or if just the
826 * eighth character is specified as '?', the correct
827 * algorithm code will be substituted and returned.
828 *
829 * Function return value:
830 * int Status return value:
831 * 0: Success.
832 * 1: Null wcsprm pointer passed.
833 * 2: Memory allocation failed.
834 * 3: Linear transformation matrix is singular.
835 * 4: Inconsistent or unrecognized coordinate axis
836 * types.
837 * 5: Invalid parameter value.
838 * 6: Invalid coordinate transformation parameters.
839 * 7: Ill-conditioned coordinate transformation
840 * parameters.
841 * 12: Invalid subimage specification (no spectral
842 * axis).
843 *
844 * For returns > 1, a detailed error message is set in
845 * wcsprm::err if enabled, see wcserr_enable().
846 *
847 *
848 * wcslib_version() - WCSLIB version number
849 * ----------------------------------------
850 * wcslib_version() returns the WCSLIB version number.
851 *
852 * The major version number changes when the ABI changes or when the license
853 * conditions change. ABI changes typically result from a change to the
854 * contents of one of the structs. The major version number is used to
855 * distinguish between incompatible versions of the sharable library.
856 *
857 * The minor version number changes with new functionality or bug fixes that do
858 * not involve a change in the ABI.
859 *
860 * The auxiliary version number (which is often absent) signals changes to the
861 * documentation, test suite, build procedures, or any other change that does
862 * not affect the compiled library.
863 *
864 * Returned:
865 * vers[3] int[3] The broken-down version number:
866 * 0: Major version number.
867 * 1: Minor version number.
868 * 2: Auxiliary version number (zero if absent).
869 * May be given as a null pointer if not required.
870 *
871 * Function return value:
872 * char* A null-terminated, statically allocated string
873 * containing the version number in the usual form, i.e.
874 * "<major>.<minor>.<auxiliary>".
875 *
876 *
877 * wcsprm struct - Coordinate transformation parameters
878 * ----------------------------------------------------
879 * The wcsprm struct contains information required to transform world
880 * coordinates. It consists of certain members that must be set by the user
881 * ("given") and others that are set by the WCSLIB routines ("returned").
882 * While the addresses of the arrays themselves may be set by wcsinit() if it
883 * (optionally) allocates memory, their contents must be set by the user.
884 *
885 * Some parameters that are given are not actually required for transforming
886 * coordinates. These are described as "auxiliary"; the struct simply provides
887 * a place to store them, though they may be used by wcshdo() in constructing a
888 * FITS header from a wcsprm struct. Some of the returned values are supplied
889 * for informational purposes and others are for internal use only as
890 * indicated.
891 *
892 * In practice, it is expected that a WCS parser would scan the FITS header to
893 * determine the number of coordinate axes. It would then use wcsinit() to
894 * allocate memory for arrays in the wcsprm struct and set default values.
895 * Then as it reread the header and identified each WCS keyrecord it would load
896 * the value into the relevant wcsprm array element. This is essentially what
897 * wcspih() does - refer to the prologue of wcshdr.h. As the final step,
898 * wcsset() is invoked, either directly or indirectly, to set the derived
899 * members of the wcsprm struct. wcsset() strips off trailing blanks in all
900 * string members and null-fills the character array.
901 *
902 * int flag
903 * (Given and returned) This flag must be set to zero whenever any of the
904 * following wcsprm struct members are set or changed:
905 *
906 * - wcsprm::naxis (q.v., not normally set by the user),
907 * - wcsprm::crpix,
908 * - wcsprm::pc,
909 * - wcsprm::cdelt,
910 * - wcsprm::crval,
911 * - wcsprm::cunit,
912 * - wcsprm::ctype,
913 * - wcsprm::lonpole,
914 * - wcsprm::latpole,
915 * - wcsprm::restfrq,
916 * - wcsprm::restwav,
917 * - wcsprm::npv,
918 * - wcsprm::pv,
919 * - wcsprm::nps,
920 * - wcsprm::ps,
921 * - wcsprm::cd,
922 * - wcsprm::crota,
923 * - wcsprm::altlin,
924 * - wcsprm::ntab,
925 * - wcsprm::nwtb,
926 * - wcsprm::tab,
927 * - wcsprm::wtb.
928 *
929 * This signals the initialization routine, wcsset(), to recompute the
930 * returned members of the celprm struct. celset() will reset flag to
931 * indicate that this has been done.
932 *
933 * PLEASE NOTE: flag should be set to -1 when wcsinit() is called for the
934 * first time for a particular wcsprm struct in order to initialize memory
935 * management. It must ONLY be used on the first initialization otherwise
936 * memory leaks may result.
937 *
938 * int naxis
939 * (Given or returned) Number of pixel and world coordinate elements.
940 *
941 * If wcsinit() is used to initialize the linprm struct (as would normally
942 * be the case) then it will set naxis from the value passed to it as a
943 * function argument. The user should not subsequently modify it.
944 *
945 * double *crpix
946 * (Given) Address of the first element of an array of double containing
947 * the coordinate reference pixel, CRPIXja.
948 *
949 * double *pc
950 * (Given) Address of the first element of the PCi_ja (pixel coordinate)
951 * transformation matrix. The expected order is
952 *
953 = struct wcsprm wcs;
954 = wcs.pc = {PC1_1, PC1_2, PC2_1, PC2_2};
955 *
956 * This may be constructed conveniently from a 2-D array via
957 *
958 = double m[2][2] = {{PC1_1, PC1_2},
959 = {PC2_1, PC2_2}};
960 *
961 * which is equivalent to
962 *
963 = double m[2][2];
964 = m[0][0] = PC1_1;
965 = m[0][1] = PC1_2;
966 = m[1][0] = PC2_1;
967 = m[1][1] = PC2_2;
968 *
969 * The storage order for this 2-D array is the same as for the 1-D array,
970 * whence
971 *
972 = wcs.pc = *m;
973 *
974 * would be legitimate.
975 *
976 * double *cdelt
977 * (Given) Address of the first element of an array of double containing
978 * the coordinate increments, CDELTia.
979 *
980 * double *crval
981 * (Given) Address of the first element of an array of double containing
982 * the coordinate reference values, CRVALia.
983 *
984 * char (*cunit)[72]
985 * (Given) Address of the first element of an array of char[72] containing
986 * the CUNITia keyvalues which define the units of measurement of the
987 * CRVALia, CDELTia, and CDi_ja keywords.
988 *
989 * As CUNITia is an optional header keyword, cunit[][72] may be left blank
990 * but otherwise is expected to contain a standard units specification as
991 * defined by WCS Paper I. Utility function wcsutrn(), described in
992 * wcsunits.h, is available to translate commonly used non-standard units
993 * specifications but this must be done as a separate step before invoking
994 * wcsset().
995 *
996 * For celestial axes, if cunit[][72] is not blank, wcsset() uses
997 * wcsunits() to parse it and scale cdelt[], crval[], and cd[][*] to
998 * degrees. It then resets cunit[][72] to "deg".
999 *
1000 * For spectral axes, if cunit[][72] is not blank, wcsset() uses wcsunits()
1001 * to parse it and scale cdelt[], crval[], and cd[][*] to SI units. It
1002 * then resets cunit[][72] accordingly.
1003 *
1004 * wcsset() ignores cunit[][72] for other coordinate types; cunit[][72] may
1005 * be used to label coordinate values.
1006 *
1007 * These variables accomodate the longest allowed string-valued FITS
1008 * keyword, being limited to 68 characters, plus the null-terminating
1009 * character.
1010 *
1011 * char (*ctype)[72]
1012 * (Given) Address of the first element of an array of char[72] containing
1013 * the coordinate axis types, CTYPEia.
1014 *
1015 * The ctype[][72] keyword values must be in upper case and there must be
1016 * zero or one pair of matched celestial axis types, and zero or one
1017 * spectral axis. The ctype[][72] strings should be padded with blanks on
1018 * the right and null-terminated so that they are at least eight characters
1019 * in length.
1020 *
1021 * These variables accomodate the longest allowed string-valued FITS
1022 * keyword, being limited to 68 characters, plus the null-terminating
1023 * character.
1024 *
1025 * double lonpole
1026 * (Given and returned) The native longitude of the celestial pole, phi_p,
1027 * given by LONPOLEa [deg] or by PVi_2a [deg] attached to the longitude
1028 * axis which takes precedence if defined, and ...
1029 * double latpole
1030 * (Given and returned) ... the native latitude of the celestial pole,
1031 * theta_p, given by LATPOLEa [deg] or by PVi_3a [deg] attached to the
1032 * longitude axis which takes precedence if defined.
1033 *
1034 * lonpole and latpole may be left to default to values set by wcsinit()
1035 * (see celprm::ref), but in any case they will be reset by wcsset() to
1036 * the values actually used. Note therefore that if the wcsprm struct is
1037 * reused without resetting them, whether directly or via wcsinit(), they
1038 * will no longer have their default values.
1039 *
1040 * double restfrq
1041 * (Given) The rest frequency [Hz], and/or ...
1042 * double restwav
1043 * (Given) ... the rest wavelength in vacuo [m], only one of which need be
1044 * given, the other should be set to zero.
1045 *
1046 * int npv
1047 * (Given) The number of entries in the wcsprm::pv[] array.
1048 *
1049 * int npvmax
1050 * (Given or returned) The length of the wcsprm::pv[] array.
1051 *
1052 * npvmax will be set by wcsinit() if it allocates memory for wcsprm::pv[],
1053 * otherwise it must be set by the user. See also wcsnpv().
1054 *
1055 * struct pvcard *pv
1056 * (Given) Address of the first element of an array of length npvmax of
1057 * pvcard structs.
1058 *
1059 * As a FITS header parser encounters each PVi_ma keyword it should load it
1060 * into a pvcard struct in the array and increment npv. wcsset()
1061 * interprets these as required.
1062 *
1063 * Note that, if they were not given, wcsset() resets the entries for
1064 * PVi_1a, PVi_2a, PVi_3a, and PVi_4a for longitude axis i to match
1065 * phi_0 and theta_0 (the native longitude and latitude of the reference
1066 * point), LONPOLEa and LATPOLEa respectively.
1067 *
1068 * int nps
1069 * (Given) The number of entries in the wcsprm::ps[] array.
1070 *
1071 * int npsmax
1072 * (Given or returned) The length of the wcsprm::ps[] array.
1073 *
1074 * npsmax will be set by wcsinit() if it allocates memory for wcsprm::ps[],
1075 * otherwise it must be set by the user. See also wcsnps().
1076 *
1077 * struct pscard *ps
1078 * (Given) Address of the first element of an array of length npsmax of
1079 * pscard structs.
1080 *
1081 * As a FITS header parser encounters each PSi_ma keyword it should load it
1082 * into a pscard struct in the array and increment nps. wcsset()
1083 * interprets these as required (currently no PSi_ma keyvalues are
1084 * recognized).
1085 *
1086 * double *cd
1087 * (Given) For historical compatibility, the wcsprm struct supports two
1088 * alternate specifications of the linear transformation matrix, those
1089 * associated with the CDi_ja keywords, and ...
1090 * double *crota
1091 * (Given) ... those associated with the CROTAi keywords. Although these
1092 * may not formally co-exist with PCi_ja, the approach taken here is simply
1093 * to ignore them if given in conjunction with PCi_ja.
1094 *
1095 * int altlin
1096 * (Given) altlin is a bit flag that denotes which of the PCi_ja, CDi_ja
1097 * and CROTAi keywords are present in the header:
1098 *
1099 * - Bit 0: PCi_ja is present.
1100 *
1101 * - Bit 1: CDi_ja is present.
1102 *
1103 * Matrix elements in the IRAF convention are
1104 * equivalent to the product CDi_ja = CDELTia * PCi_ja, but the
1105 * defaults differ from that of the PCi_ja matrix. If one or more
1106 * CDi_ja keywords are present then all unspecified CDi_ja default to
1107 * zero. If no CDi_ja (or CROTAi) keywords are present, then the
1108 * header is assumed to be in PCi_ja form whether or not any PCi_ja
1109 * keywords are present since this results in an interpretation of
1110 * CDELTia consistent with the original FITS specification.
1111 *
1112 * While CDi_ja may not formally co-exist with PCi_ja, it may co-exist
1113 * with CDELTia and CROTAi which are to be ignored.
1114 *
1115 * - Bit 2: CROTAi is present.
1116 *
1117 * In the AIPS convention, CROTAi may only be
1118 * associated with the latitude axis of a celestial axis pair. It
1119 * specifies a rotation in the image plane that is applied AFTER the
1120 * CDELTia; any other CROTAi keywords are ignored.
1121 *
1122 * CROTAi may not formally co-exist with PCi_ja.
1123 *
1124 * CROTAi and CDELTia may formally co-exist with CDi_ja but if so are to
1125 * be ignored.
1126 *
1127 * CDi_ja and CROTAi keywords, if found, are to be stored in the
1128 * wcsprm::cd and wcsprm::crota arrays which are dimensioned similarly to
1129 * wcsprm::pc and wcsprm::cdelt. FITS
1130 * header parsers should use the following procedure:
1131 *
1132 * - Whenever a PCi_ja keyword is encountered: altlin |= 1;
1133 *
1134 * - Whenever a CDi_ja keyword is encountered: altlin |= 2;
1135 *
1136 * - Whenever a CROTAi keyword is encountered: altlin |= 4;
1137 *
1138 * If none of these bits are set the PCi_ja representation results, i.e.
1139 * wcsprm::pc and wcsprm::cdelt will be used as given.
1140 *
1141 * These alternate specifications of the linear transformation matrix are
1142 * translated immediately to PCi_ja by wcsset() and are invisible to the
1143 * lower-level WCSLIB routines. In particular, wcsset() resets
1144 * wcsprm::cdelt to unity if CDi_ja is present (and no PCi_ja).
1145 *
1146 * If CROTAi are present but none is associated with the latitude axis
1147 * (and no PCi_ja or CDi_ja), then wcsset() reverts to a unity PCi_ja
1148 * matrix.
1149 *
1150 * int velref
1151 * (Given) AIPS velocity code VELREF, refer to spcaips().
1152 *
1153 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1154 * wcsprm::velref is changed.
1155 *
1156 * char alt[4]
1157 * (Given, auxiliary) Character code for alternate coordinate descriptions
1158 * (i.e. the 'a' in keyword names such as CTYPEia). This is blank for the
1159 * primary coordinate description, or one of the 26 upper-case letters,
1160 * A-Z.
1161 *
1162 * An array of four characters is provided for alignment purposes, only the
1163 * first is used.
1164 *
1165 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1166 * wcsprm::alt is changed.
1167 *
1168 * int colnum
1169 * (Given, auxiliary) Where the coordinate representation is associated
1170 * with an image-array column in a FITS binary table, this variable may be
1171 * used to record the relevant column number.
1172 *
1173 * It should be set to zero for an image header or pixel list.
1174 *
1175 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1176 * wcsprm::colnum is changed.
1177 *
1178 * int *colax
1179 * (Given, auxiliary) Address of the first element of an array of int
1180 * recording the column numbers for each axis in a pixel list.
1181 *
1182 * The array elements should be set to zero for an image header or image
1183 * array in a binary table.
1184 *
1185 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1186 * wcsprm::colax is changed.
1187 *
1188 * char (*cname)[72]
1189 * (Given, auxiliary) The address of the first element of an array of
1190 * char[72] containing the coordinate axis names, CNAMEia.
1191 *
1192 * These variables accomodate the longest allowed string-valued FITS
1193 * keyword, being limited to 68 characters, plus the null-terminating
1194 * character.
1195 *
1196 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1197 * wcsprm::cname is changed.
1198 *
1199 * double *crder
1200 * (Given, auxiliary) Address of the first element of an array of double
1201 * recording the random error in the coordinate value, CRDERia.
1202 *
1203 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1204 * wcsprm::crder is changed.
1205 *
1206 * double *csyer
1207 * (Given, auxiliary) Address of the first element of an array of double
1208 * recording the systematic error in the coordinate value, CSYERia.
1209 *
1210 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1211 * wcsprm::csyer is changed.
1212 *
1213 * double *czphs
1214 * (Given, auxiliary) Address of the first element of an array of double
1215 * recording the time at the zero point of a phase axis, CZPHSia.
1216 *
1217 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1218 * wcsprm::czphs is changed.
1219 *
1220 * double *cperi
1221 * (Given, auxiliary) Address of the first element of an array of double
1222 * recording the period of a phase axis, CPERIia.
1223 *
1224 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1225 * wcsprm::cperi is changed.
1226 *
1227 * char wcsname[72]
1228 * (Given, auxiliary) The name given to the coordinate representation,
1229 * WCSNAMEa. This variable accomodates the longest allowed string-valued
1230 * FITS keyword, being limited to 68 characters, plus the null-terminating
1231 * character.
1232 *
1233 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1234 * wcsprm::wcsname is changed.
1235 *
1236 * char timesys[72]
1237 * (Given, auxiliary) TIMESYS keyvalue, being the time scale (UTC, TAI,
1238 * etc.) in which all other time-related auxiliary header values are
1239 * recorded. Also defines the time scale for an image axis with CTYPEia
1240 * set to 'TIME'.
1241 *
1242 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1243 * wcsprm::timesys is changed.
1244 *
1245 * char trefpos[72]
1246 * (Given, auxiliary) TREFPOS keyvalue, being the location in space where
1247 * the recorded time is valid.
1248 *
1249 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1250 * wcsprm::trefpos is changed.
1251 *
1252 * char trefdir[72]
1253 * (Given, auxiliary) TREFDIR keyvalue, being the reference direction used
1254 * in calculating a pathlength delay.
1255 *
1256 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1257 * wcsprm::trefdir is changed.
1258 *
1259 * char plephem[72]
1260 * (Given, auxiliary) PLEPHEM keyvalue, being the Solar System ephemeris
1261 * used for calculating a pathlength delay.
1262 *
1263 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1264 * wcsprm::plephem is changed.
1265 *
1266 * char timeunit[72]
1267 * (Given, auxiliary) TIMEUNIT keyvalue, being the time units in which
1268 * the following header values are expressed: TSTART, TSTOP, TIMEOFFS,
1269 * TIMSYER, TIMRDER, TIMEDEL. It also provides the default value for
1270 * CUNITia for time axes.
1271 *
1272 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1273 * wcsprm::timeunit is changed.
1274 *
1275 * char dateref[72]
1276 * (Given, auxiliary) DATEREF keyvalue, being the date of a reference epoch
1277 * relative to which other time measurements refer.
1278 *
1279 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1280 * wcsprm::dateref is changed.
1281 *
1282 * double mjdref[2]
1283 * (Given, auxiliary) MJDREF keyvalue, equivalent to DATEREF expressed as
1284 * a Modified Julian Date (MJD = JD - 2400000.5). The value is given as
1285 * the sum of the two-element vector, allowing increased precision.
1286 *
1287 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1288 * wcsprm::mjdref is changed.
1289 *
1290 * double timeoffs
1291 * (Given, auxiliary) TIMEOFFS keyvalue, being a time offset, which may be
1292 * used, for example, to provide a uniform clock correction for times
1293 * referenced to DATEREF.
1294 *
1295 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1296 * wcsprm::timeoffs is changed.
1297 *
1298 * char dateobs[72]
1299 * (Given, auxiliary) DATE-OBS keyvalue, being the date at the start of the
1300 * observation unless otherwise explained in the DATE-OBS keycomment, in
1301 * ISO format, yyyy-mm-ddThh:mm:ss.
1302 *
1303 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1304 * wcsprm::dateobs is changed.
1305 *
1306 * char datebeg[72]
1307 * (Given, auxiliary) DATE-BEG keyvalue, being the date at the start of the
1308 * observation in ISO format, yyyy-mm-ddThh:mm:ss.
1309 *
1310 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1311 * wcsprm::datebeg is changed.
1312 *
1313 * char dateavg[72]
1314 * (Given, auxiliary) DATE-AVG keyvalue, being the date at a representative
1315 * mid-point of the observation in ISO format, yyyy-mm-ddThh:mm:ss.
1316 *
1317 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1318 * wcsprm::dateavg is changed.
1319 *
1320 * char dateend[72]
1321 * (Given, auxiliary) DATE-END keyvalue, baing the date at the end of the
1322 * observation in ISO format, yyyy-mm-ddThh:mm:ss.
1323 *
1324 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1325 * wcsprm::dateend is changed.
1326 *
1327 * double mjdobs
1328 * (Given, auxiliary) MJD-OBS keyvalue, equivalent to DATE-OBS expressed
1329 * as a Modified Julian Date (MJD = JD - 2400000.5).
1330 *
1331 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1332 * wcsprm::mjdobs is changed.
1333 *
1334 * double mjdbeg
1335 * (Given, auxiliary) MJD-BEG keyvalue, equivalent to DATE-BEG expressed
1336 * as a Modified Julian Date (MJD = JD - 2400000.5).
1337 *
1338 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1339 * wcsprm::mjdbeg is changed.
1340 *
1341 * double mjdavg
1342 * (Given, auxiliary) MJD-AVG keyvalue, equivalent to DATE-AVG expressed
1343 * as a Modified Julian Date (MJD = JD - 2400000.5).
1344 *
1345 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1346 * wcsprm::mjdavg is changed.
1347 *
1348 * double mjdend
1349 * (Given, auxiliary) MJD-END keyvalue, equivalent to DATE-END expressed
1350 * as a Modified Julian Date (MJD = JD - 2400000.5).
1351 *
1352 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1353 * wcsprm::mjdend is changed.
1354 *
1355 * double jepoch
1356 * (Given, auxiliary) JEPOCH keyvalue, equivalent to DATE-OBS expressed
1357 * as a Julian epoch.
1358 *
1359 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1360 * wcsprm::jepoch is changed.
1361 *
1362 * double bepoch
1363 * (Given, auxiliary) BEPOCH keyvalue, equivalent to DATE-OBS expressed
1364 * as a Besselian epoch
1365 *
1366 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1367 * wcsprm::bepoch is changed.
1368 *
1369 * double tstart
1370 * (Given, auxiliary) TSTART keyvalue, equivalent to DATE-BEG expressed
1371 * as a time in units of TIMEUNIT relative to DATEREF+TIMEOFFS.
1372 *
1373 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1374 * wcsprm::tstart is changed.
1375 *
1376 * double tstop
1377 * (Given, auxiliary) TSTOP keyvalue, equivalent to DATE-END expressed
1378 * as a time in units of TIMEUNIT relative to DATEREF+TIMEOFFS.
1379 *
1380 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1381 * wcsprm::tstop is changed.
1382 *
1383 * double xposure
1384 * (Given, auxiliary) XPOSURE keyvalue, being the effective exposure time
1385 * in units of TIMEUNIT.
1386 *
1387 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1388 * wcsprm::xposure is changed.
1389 *
1390 * double telapse
1391 * (Given, auxiliary) TELAPSE keyvalue, equivalent to the elapsed time
1392 * between DATE-BEG and DATE-END, in units of TIMEUNIT.
1393 *
1394 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1395 * wcsprm::telapse is changed.
1396 *
1397 * double timsyer
1398 * (Given, auxiliary) TIMSYER keyvalue, being the absolute error of the
1399 * time values, in units of TIMEUNIT.
1400 *
1401 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1402 * wcsprm::timsyer is changed.
1403 *
1404 * double timrder
1405 * (Given, auxiliary) TIMRDER keyvalue, being the accuracy of time stamps
1406 * relative to each other, in units of TIMEUNIT.
1407 *
1408 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1409 * wcsprm::timrder is changed.
1410 *
1411 * double timedel
1412 * (Given, auxiliary) TIMEDEL keyvalue, being the resolution of the time
1413 * stamps.
1414 *
1415 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1416 * wcsprm::timedel is changed.
1417 *
1418 * double timepixr
1419 * (Given, auxiliary) TIMEPIXR keyvalue, being the relative position of the
1420 * time stamps in binned time intervals, a value between 0.0 and 1.0.
1421 *
1422 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1423 * wcsprm::timepixr is changed.
1424 *
1425 * double obsgeo[6]
1426 * (Given, auxiliary) Location of the observer in a standard terrestrial
1427 * reference frame. The first three give ITRS Cartesian coordinates
1428 * OBSGEO-X [m], OBSGEO-Y [m], OBSGEO-Z [m], and the second three give
1429 * OBSGEO-L [deg], OBSGEO-B [deg], OBSGEO-H [m], which are related through
1430 * a standard transformation.
1431 *
1432 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1433 * wcsprm::obsgeo is changed.
1434 *
1435 * char obsorbit[72]
1436 * (Given, auxiliary) OBSORBIT keyvalue, being the URI, URL, or name of an
1437 * orbit ephemeris file giving spacecraft coordinates relating to TREFPOS.
1438 *
1439 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1440 * wcsprm::obsorbit is changed.
1441 *
1442 * char radesys[72]
1443 * (Given, auxiliary) The equatorial or ecliptic coordinate system type,
1444 * RADESYSa.
1445 *
1446 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1447 * wcsprm::radesys is changed.
1448 *
1449 * double equinox
1450 * (Given, auxiliary) The equinox associated with dynamical equatorial or
1451 * ecliptic coordinate systems, EQUINOXa (or EPOCH in older headers). Not
1452 * applicable to ICRS equatorial or ecliptic coordinates.
1453 *
1454 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1455 * wcsprm::equinox is changed.
1456 *
1457 * char specsys[72]
1458 * (Given, auxiliary) Spectral reference frame (standard of rest),
1459 * SPECSYSa.
1460 *
1461 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1462 * wcsprm::specsys is changed.
1463 *
1464 * char ssysobs[72]
1465 * (Given, auxiliary) The spectral reference frame in which there is no
1466 * differential variation in the spectral coordinate across the
1467 * field-of-view, SSYSOBSa.
1468 *
1469 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1470 * wcsprm::ssysobs is changed.
1471 *
1472 * double velosys
1473 * (Given, auxiliary) The relative radial velocity [m/s] between the
1474 * observer and the selected standard of rest in the direction of the
1475 * celestial reference coordinate, VELOSYSa.
1476 *
1477 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1478 * wcsprm::velosys is changed.
1479 *
1480 * double zsource
1481 * (Given, auxiliary) The redshift, ZSOURCEa, of the source.
1482 *
1483 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1484 * wcsprm::zsource is changed.
1485 *
1486 * char ssyssrc[72]
1487 * (Given, auxiliary) The spectral reference frame (standard of rest),
1488 * SSYSSRCa, in which wcsprm::zsource was measured.
1489 *
1490 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1491 * wcsprm::ssyssrc is changed.
1492 *
1493 * double velangl
1494 * (Given, auxiliary) The angle [deg] that should be used to decompose an
1495 * observed velocity into radial and transverse components.
1496 *
1497 * It is not necessary to reset the wcsprm struct (via wcsset()) when
1498 * wcsprm::velangl is changed.
1499 *
1500 * struct auxprm *aux
1501 * (Given, auxiliary) This struct holds auxiliary coordinate system
1502 * information of a specialist nature. While these parameters may be
1503 * widely recognized within particular fields of astronomy, they differ
1504 * from the above auxiliary parameters in not being defined by any of the
1505 * FITS WCS standards. Collecting them together in a separate struct that
1506 * is allocated only when required helps to control bloat in the size of
1507 * the wcsprm struct.
1508 *
1509 * int ntab
1510 * (Given) See wcsprm::tab.
1511 *
1512 * int nwtb
1513 * (Given) See wcsprm::wtb.
1514 *
1515 * struct tabprm *tab
1516 * (Given) Address of the first element of an array of ntab tabprm structs
1517 * for which memory has been allocated. These are used to store tabular
1518 * transformation parameters.
1519 *
1520 * Although technically wcsprm::ntab and tab are "given", they will
1521 * normally be set by invoking wcstab(), whether directly or indirectly.
1522 *
1523 * The tabprm structs contain some members that must be supplied and others
1524 * that are derived. The information to be supplied comes primarily from
1525 * arrays stored in one or more FITS binary table extensions. These
1526 * arrays, referred to here as "wcstab arrays", are themselves located by
1527 * parameters stored in the FITS image header.
1528 *
1529 * struct wtbarr *wtb
1530 * (Given) Address of the first element of an array of nwtb wtbarr structs
1531 * for which memory has been allocated. These are used in extracting
1532 * wcstab arrays from a FITS binary table.
1533 *
1534 * Although technically wcsprm::nwtb and wtb are "given", they will
1535 * normally be set by invoking wcstab(), whether directly or indirectly.
1536 *
1537 * char lngtyp[8]
1538 * (Returned) Four-character WCS celestial longitude and ...
1539 * char lattyp[8]
1540 * (Returned) ... latitude axis types. e.g. "RA", "DEC", "GLON", "GLAT",
1541 * etc. extracted from 'RA--', 'DEC-', 'GLON', 'GLAT', etc. in the first
1542 * four characters of CTYPEia but with trailing dashes removed. (Declared
1543 * as char[8] for alignment reasons.)
1544 *
1545 * int lng
1546 * (Returned) Index for the longitude coordinate, and ...
1547 * int lat
1548 * (Returned) ... index for the latitude coordinate, and ...
1549 * int spec
1550 * (Returned) ... index for the spectral coordinate in the imgcrd[][] and
1551 * world[][] arrays in the API of wcsp2s(), wcss2p() and wcsmix().
1552 *
1553 * These may also serve as indices into the pixcrd[][] array provided that
1554 * the PCi_ja matrix does not transpose axes.
1555 *
1556 * int cubeface
1557 * (Returned) Index into the pixcrd[][] array for the CUBEFACE axis. This
1558 * is used for quadcube projections where the cube faces are stored on a
1559 * separate axis (see wcs.h).
1560 *
1561 * int *types
1562 * (Returned) Address of the first element of an array of int containing a
1563 * four-digit type code for each axis.
1564 *
1565 * - First digit (i.e. 1000s):
1566 * - 0: Non-specific coordinate type.
1567 * - 1: Stokes coordinate.
1568 * - 2: Celestial coordinate (including CUBEFACE).
1569 * - 3: Spectral coordinate.
1570 *
1571 * - Second digit (i.e. 100s):
1572 * - 0: Linear axis.
1573 * - 1: Quantized axis (STOKES, CUBEFACE).
1574 * - 2: Non-linear celestial axis.
1575 * - 3: Non-linear spectral axis.
1576 * - 4: Logarithmic axis.
1577 * - 5: Tabular axis.
1578 *
1579 * - Third digit (i.e. 10s):
1580 * - 0: Group number, e.g. lookup table number, being an index into the
1581 * tabprm array (see above).
1582 *
1583 * - The fourth digit is used as a qualifier depending on the axis type.
1584 *
1585 * - For celestial axes:
1586 * - 0: Longitude coordinate.
1587 * - 1: Latitude coordinate.
1588 * - 2: CUBEFACE number.
1589 *
1590 * - For lookup tables: the axis number in a multidimensional table.
1591 *
1592 * CTYPEia in "4-3" form with unrecognized algorithm code will have its
1593 * type set to -1 and generate an error.
1594 *
1595 * struct linprm lin
1596 * (Returned) Linear transformation parameters (usage is described in the
1597 * prologue to lin.h).
1598 *
1599 * struct celprm cel
1600 * (Returned) Celestial transformation parameters (usage is described in
1601 * the prologue to cel.h).
1602 *
1603 * struct spcprm spc
1604 * (Returned) Spectral transformation parameters (usage is described in the
1605 * prologue to spc.h).
1606 *
1607 * struct wcserr *err
1608 * (Returned) If enabled, when an error status is returned, this struct
1609 * contains detailed information about the error, see wcserr_enable().
1610 *
1611 * int m_flag
1612 * (For internal use only.)
1613 * int m_naxis
1614 * (For internal use only.)
1615 * double *m_crpix
1616 * (For internal use only.)
1617 * double *m_pc
1618 * (For internal use only.)
1619 * double *m_cdelt
1620 * (For internal use only.)
1621 * double *m_crval
1622 * (For internal use only.)
1623 * char (*m_cunit)[72]
1624 * (For internal use only.)
1625 * char (*m_ctype)[72]
1626 * (For internal use only.)
1627 * struct pvcard *m_pv
1628 * (For internal use only.)
1629 * struct pscard *m_ps
1630 * (For internal use only.)
1631 * double *m_cd
1632 * (For internal use only.)
1633 * double *m_crota
1634 * (For internal use only.)
1635 * int *m_colax
1636 * (For internal use only.)
1637 * char (*m_cname)[72]
1638 * (For internal use only.)
1639 * double *m_crder
1640 * (For internal use only.)
1641 * double *m_csyer
1642 * (For internal use only.)
1643 * double *m_czphs
1644 * (For internal use only.)
1645 * double *m_cperi
1646 * (For internal use only.)
1647 * struct tabprm *m_tab
1648 * (For internal use only.)
1649 * struct wtbarr *m_wtb
1650 * (For internal use only.)
1651 *
1652 *
1653 * pvcard struct - Store for PVi_ma keyrecords
1654 * -------------------------------------------
1655 * The pvcard struct is used to pass the parsed contents of PVi_ma keyrecords
1656 * to wcsset() via the wcsprm struct.
1657 *
1658 * All members of this struct are to be set by the user.
1659 *
1660 * int i
1661 * (Given) Axis number (1-relative), as in the FITS PVi_ma keyword. If
1662 * i == 0, wcsset() will replace it with the latitude axis number.
1663 *
1664 * int m
1665 * (Given) Parameter number (non-negative), as in the FITS PVi_ma keyword.
1666 *
1667 * double value
1668 * (Given) Parameter value.
1669 *
1670 *
1671 * pscard struct - Store for PSi_ma keyrecords
1672 * -------------------------------------------
1673 * The pscard struct is used to pass the parsed contents of PSi_ma keyrecords
1674 * to wcsset() via the wcsprm struct.
1675 *
1676 * All members of this struct are to be set by the user.
1677 *
1678 * int i
1679 * (Given) Axis number (1-relative), as in the FITS PSi_ma keyword.
1680 *
1681 * int m
1682 * (Given) Parameter number (non-negative), as in the FITS PSi_ma keyword.
1683 *
1684 * char value[72]
1685 * (Given) Parameter value.
1686 *
1687 *
1688 * auxprm struct - Additional auxiliary parameters
1689 * -----------------------------------------------
1690 * The auxprm struct holds auxiliary coordinate system information of a
1691 * specialist nature. It is anticipated that this struct will expand in future
1692 * to accomodate additional parameters.
1693 *
1694 * All members of this struct are to be set by the user.
1695 *
1696 * double rsun_ref
1697 * (Given, auxiliary) Reference radius of the Sun used in coordinate
1698 * calculations (m).
1699 *
1700 * double dsun_obs
1701 * (Given, auxiliary) Distance between the centre of the Sun and the
1702 * observer (m).
1703 *
1704 * double crln_obs
1705 * (Given, auxiliary) Carrington heliographic longitude of the observer
1706 * (deg).
1707 *
1708 * double hgln_obs
1709 * (Given, auxiliary) Stonyhurst heliographic longitude of the observer
1710 * (deg).
1711 *
1712 * double hglt_obs
1713 * (Given, auxiliary) Heliographic latitude (Carrington or Stonyhurst) of
1714 * the observer (deg).
1715 *
1716 *
1717 * Global variable: const char *wcs_errmsg[] - Status return messages
1718 * ------------------------------------------------------------------
1719 * Error messages to match the status value returned from each function.
1720 *
1721 *===========================================================================*/
1722
1723 #ifndef WCSLIB_WCS
1724 #define WCSLIB_WCS
1725
1726 #include "lin.h"
1727 #include "cel.h"
1728 #include "spc.h"
1729
1730 #ifdef __cplusplus
1731 extern "C" {
1732 #define wtbarr wtbarr_s // See prologue of wtbarr.h.
1733 #endif
1734
1735 #define WCSSUB_LONGITUDE 0x1001
1736 #define WCSSUB_LATITUDE 0x1002
1737 #define WCSSUB_CUBEFACE 0x1004
1738 #define WCSSUB_CELESTIAL 0x1007
1739 #define WCSSUB_SPECTRAL 0x1008
1740 #define WCSSUB_STOKES 0x1010
1741
1742
1743 #define WCSCOMPARE_ANCILLARY 0x0001
1744 #define WCSCOMPARE_TILING 0x0002
1745 #define WCSCOMPARE_CRPIX 0x0004
1746
1747
1748 extern const char *wcs_errmsg[];
1749
1750 enum wcs_errmsg_enum {
1751 WCSERR_SUCCESS = 0, // Success.
1752 WCSERR_NULL_POINTER = 1, // Null wcsprm pointer passed.
1753 WCSERR_MEMORY = 2, // Memory allocation failed.
1754 WCSERR_SINGULAR_MTX = 3, // Linear transformation matrix is singular.
1755 WCSERR_BAD_CTYPE = 4, // Inconsistent or unrecognized coordinate
1756 // axis type.
1757 WCSERR_BAD_PARAM = 5, // Invalid parameter value.
1758 WCSERR_BAD_COORD_TRANS = 6, // Unrecognized coordinate transformation
1759 // parameter.
1760 WCSERR_ILL_COORD_TRANS = 7, // Ill-conditioned coordinate transformation
1761 // parameter.
1762 WCSERR_BAD_PIX = 8, // One or more of the pixel coordinates were
1763 // invalid.
1764 WCSERR_BAD_WORLD = 9, // One or more of the world coordinates were
1765 // invalid.
1766 WCSERR_BAD_WORLD_COORD = 10, // Invalid world coordinate.
1767 WCSERR_NO_SOLUTION = 11, // No solution found in the specified
1768 // interval.
1769 WCSERR_BAD_SUBIMAGE = 12, // Invalid subimage specification.
1770 WCSERR_NON_SEPARABLE = 13 // Non-separable subimage coordinate system.
1771 };
1772
1773
1774 // Struct used for storing PVi_ma keywords.
1775 struct pvcard {
1776 int i; // Axis number, as in PVi_ma (1-relative).
1777 int m; // Parameter number, ditto (0-relative).
1778 double value; // Parameter value.
1779 };
1780
1781 // Size of the pvcard struct in int units, used by the Fortran wrappers.
1782 #define PVLEN (sizeof(struct pvcard)/sizeof(int))
1783
1784 // Struct used for storing PSi_ma keywords.
1785 struct pscard {
1786 int i; // Axis number, as in PSi_ma (1-relative).
1787 int m; // Parameter number, ditto (0-relative).
1788 char value[72]; // Parameter value.
1789 };
1790
1791 // Size of the pscard struct in int units, used by the Fortran wrappers.
1792 #define PSLEN (sizeof(struct pscard)/sizeof(int))
1793
1794 // Struct used to hold additional auxiliary parameters.
1795 struct auxprm {
1796 double rsun_ref; // Solar radius.
1797 double dsun_obs; // Distance from Sun centre to observer.
1798 double crln_obs; // Carrington heliographic lng of observer.
1799 double hgln_obs; // Stonyhurst heliographic lng of observer.
1800 double hglt_obs; // Heliographic latitude of observer.
1801 };
1802
1803 // Size of the auxprm struct in int units, used by the Fortran wrappers.
1804 #define AUXLEN (sizeof(struct auxprm)/sizeof(int))
1805
1806
1807 struct wcsprm {
1808 // Initialization flag (see the prologue above).
1809 //--------------------------------------------------------------------------
1810 int flag; // Set to zero to force initialization.
1811
1812 // FITS header keyvalues to be provided (see the prologue above).
1813 //--------------------------------------------------------------------------
1814 int naxis; // Number of axes (pixel and coordinate).
1815 double *crpix; // CRPIXja keyvalues for each pixel axis.
1816 double *pc; // PCi_ja linear transformation matrix.
1817 double *cdelt; // CDELTia keyvalues for each coord axis.
1818 double *crval; // CRVALia keyvalues for each coord axis.
1819
1820 char (*cunit)[72]; // CUNITia keyvalues for each coord axis.
1821 char (*ctype)[72]; // CTYPEia keyvalues for each coord axis.
1822
1823 double lonpole; // LONPOLEa keyvalue.
1824 double latpole; // LATPOLEa keyvalue.
1825
1826 double restfrq; // RESTFRQa keyvalue.
1827 double restwav; // RESTWAVa keyvalue.
1828
1829 int npv; // Number of PVi_ma keywords, and the
1830 int npvmax; // number for which space was allocated.
1831 struct pvcard *pv; // PVi_ma keywords for each i and m.
1832
1833 int nps; // Number of PSi_ma keywords, and the
1834 int npsmax; // number for which space was allocated.
1835 struct pscard *ps; // PSi_ma keywords for each i and m.
1836
1837 // Alternative header keyvalues (see the prologue above).
1838 //--------------------------------------------------------------------------
1839 double *cd; // CDi_ja linear transformation matrix.
1840 double *crota; // CROTAi keyvalues for each coord axis.
1841 int altlin; // Alternative representations
1842 // Bit 0: PCi_ja is present,
1843 // Bit 1: CDi_ja is present,
1844 // Bit 2: CROTAi is present.
1845 int velref; // AIPS velocity code, VELREF.
1846
1847 // Auxiliary coordinate system information of a general nature. Not
1848 // used by WCSLIB. Refer to the prologue comments above for a brief
1849 // explanation of these values.
1850 char alt[4];
1851 int colnum;
1852 int *colax;
1853 // Auxiliary coordinate axis information.
1854 char (*cname)[72];
1855 double *crder;
1856 double *csyer;
1857 double *czphs;
1858 double *cperi;
1859
1860 char wcsname[72];
1861 // Time reference system and measurement.
1862 char timesys[72], trefpos[72], trefdir[72], plephem[72];
1863 char timeunit[72];
1864 char dateref[72];
1865 double mjdref[2];
1866 double timeoffs;
1867 // Data timestamps and durations.
1868 char dateobs[72], datebeg[72], dateavg[72], dateend[72];
1869 double mjdobs, mjdbeg, mjdavg, mjdend;
1870 double jepoch, bepoch;
1871 double tstart, tstop;
1872 double xposure, telapse;
1873 // Timing accuracy.
1874 double timsyer, timrder;
1875 double timedel, timepixr;
1876 // Spatial & celestial reference frame.
1877 double obsgeo[6];
1878 char obsorbit[72];
1879 char radesys[72];
1880 double equinox;
1881 char specsys[72];
1882 char ssysobs[72];
1883 double velosys;
1884 double zsource;
1885 char ssyssrc[72];
1886 double velangl;
1887
1888 // Additional auxiliary coordinate system information of a specialist
1889 // nature. Not used by WCSLIB. Refer to the prologue comments above.
1890 struct auxprm *aux;
1891
1892 // Coordinate lookup tables (see the prologue above).
1893 //--------------------------------------------------------------------------
1894 int ntab; // Number of separate tables.
1895 int nwtb; // Number of wtbarr structs.
1896 struct tabprm *tab; // Tabular transformation parameters.
1897 struct wtbarr *wtb; // Array of wtbarr structs.
1898
1899 //--------------------------------------------------------------------------
1900 // Information derived from the FITS header keyvalues by wcsset().
1901 //--------------------------------------------------------------------------
1902 char lngtyp[8], lattyp[8]; // Celestial axis types, e.g. RA, DEC.
1903 int lng, lat, spec; // Longitude, latitude and spectral axis
1904 // indices (0-relative).
1905 int cubeface; // True if there is a CUBEFACE axis.
1906 int *types; // Coordinate type codes for each axis.
1907
1908 struct linprm lin; // Linear transformation parameters.
1909 struct celprm cel; // Celestial transformation parameters.
1910 struct spcprm spc; // Spectral transformation parameters.
1911
1912 //--------------------------------------------------------------------------
1913 // THE REMAINDER OF THE WCSPRM STRUCT IS PRIVATE.
1914 //--------------------------------------------------------------------------
1915
1916 // Error handling, if enabled.
1917 //--------------------------------------------------------------------------
1918 struct wcserr *err;
1919
1920 // Memory management.
1921 //--------------------------------------------------------------------------
1922 int m_flag, m_naxis;
1923 double *m_crpix, *m_pc, *m_cdelt, *m_crval;
1924 char (*m_cunit)[72], (*m_ctype)[72];
1925 struct pvcard *m_pv;
1926 struct pscard *m_ps;
1927 double *m_cd, *m_crota;
1928 int *m_colax;
1929 char (*m_cname)[72];
1930 double *m_crder, *m_csyer, *m_czphs, *m_cperi;
1931 struct auxprm *m_aux;
1932 struct tabprm *m_tab;
1933 struct wtbarr *m_wtb;
1934 };
1935
1936 // Size of the wcsprm struct in int units, used by the Fortran wrappers.
1937 #define WCSLEN (sizeof(struct wcsprm)/sizeof(int))
1938
1939
1940 int wcsnpv(int n);
1941
1942 int wcsnps(int n);
1943
1944 int wcsini(int alloc, int naxis, struct wcsprm *wcs);
1945
1946 int wcsinit(int alloc, int naxis, struct wcsprm *wcs, int npvmax, int npsmax,
1947 int ndpmax);
1948
1949 int wcsauxi(int alloc, struct wcsprm *wcs);
1950
1951 int wcssub(int alloc, const struct wcsprm *wcssrc, int *nsub, int axes[],
1952 struct wcsprm *wcsdst);
1953
1954 int wcscompare(int cmp, double tol, const struct wcsprm *wcs1,
1955 const struct wcsprm *wcs2, int *equal);
1956
1957 int wcsfree(struct wcsprm *wcs);
1958
1959 int wcsprt(const struct wcsprm *wcs);
1960
1961 int wcsperr(const struct wcsprm *wcs, const char *prefix);
1962
1963 int wcsbchk(struct wcsprm *wcs, int bounds);
1964
1965 int wcsset(struct wcsprm *wcs);
1966
1967 int wcsp2s(struct wcsprm *wcs, int ncoord, int nelem, const double pixcrd[],
1968 double imgcrd[], double phi[], double theta[], double world[],
1969 int stat[]);
1970
1971 int wcss2p(struct wcsprm *wcs, int ncoord, int nelem, const double world[],
1972 double phi[], double theta[], double imgcrd[], double pixcrd[],
1973 int stat[]);
1974
1975 int wcsmix(struct wcsprm *wcs, int mixpix, int mixcel, const double vspan[],
1976 double vstep, int viter, double world[], double phi[],
1977 double theta[], double imgcrd[], double pixcrd[]);
1978
1979 int wcssptr(struct wcsprm *wcs, int *i, char ctype[9]);
1980
1981 const char* wcslib_version(int vers[3]);
1982
1983 // Defined mainly for backwards compatibility, use wcssub() instead.
1984 #define wcscopy(alloc, wcssrc, wcsdst) wcssub(alloc, wcssrc, 0x0, 0x0, wcsdst)
1985
1986
1987 // Deprecated.
1988 #define wcsini_errmsg wcs_errmsg
1989 #define wcssub_errmsg wcs_errmsg
1990 #define wcscopy_errmsg wcs_errmsg
1991 #define wcsfree_errmsg wcs_errmsg
1992 #define wcsprt_errmsg wcs_errmsg
1993 #define wcsset_errmsg wcs_errmsg
1994 #define wcsp2s_errmsg wcs_errmsg
1995 #define wcss2p_errmsg wcs_errmsg
1996 #define wcsmix_errmsg wcs_errmsg
1997
1998 #ifdef __cplusplus
1999 #undef wtbarr
2000 }
2001 #endif
2002
2003 #endif // WCSLIB_WCS
pscard::m
int m
Definition: wcs.h:1787
wcsprm::timepixr
double timepixr
Definition: wcs.h:1875
wcsprm::m_pv
struct pvcard * m_pv
Definition: wcs.h:1925
wcsprm::nps
int nps
Definition: wcs.h:1833
wcsprm::timesys
char timesys[72]
Definition: wcs.h:1862
pscard::value
char value[72]
Definition: wcs.h:1788
auxprm::crln_obs
double crln_obs
Definition: wcs.h:1798
wcsprm::dateref
char dateref[72]
Definition: wcs.h:1864
wcsprm::cel
struct celprm cel
Definition: wcs.h:1909
wcsprm::spec
int spec
Definition: wcs.h:1903
wcsprm::ssysobs
char ssysobs[72]
Definition: wcs.h:1882
wcsprm::cubeface
int cubeface
Definition: wcs.h:1905
wcsprm::trefdir
char trefdir[72]
Definition: wcs.h:1862
wcsprm::dateobs
char dateobs[72]
Definition: wcs.h:1868
cel.h
wcsprm::m_crota
double * m_crota
Definition: wcs.h:1927
wcsprm::m_tab
struct tabprm * m_tab
Definition: wcs.h:1932
WCSERR_BAD_PIX
@ WCSERR_BAD_PIX
Definition: wcs.h:1762
WCSERR_ILL_COORD_TRANS
@ WCSERR_ILL_COORD_TRANS
Definition: wcs.h:1760
WCSERR_NULL_POINTER
@ WCSERR_NULL_POINTER
Definition: wcs.h:1752
wcsprm::lng
int lng
Definition: wcs.h:1903
wcslib_version
const char * wcslib_version(int vers[3])
wcscompare
int wcscompare(int cmp, double tol, const struct wcsprm *wcs1, const struct wcsprm *wcs2, int *equal)
Compare two wcsprm structs for equality.
spc.h
wcsprm::m_cname
char(* m_cname)[72]
Definition: wcs.h:1929
wcsprm::lngtyp
char lngtyp[8]
Definition: wcs.h:1902
wcsinit
int wcsinit(int alloc, int naxis, struct wcsprm *wcs, int npvmax, int npsmax, int ndpmax)
Default constructor for the wcsprm struct.
wcsprm::crota
double * crota
Definition: wcs.h:1840
wcsprm::lat
int lat
Definition: wcs.h:1903
wcsprm::obsorbit
char obsorbit[72]
Definition: wcs.h:1878
wcsprm::dateavg
char dateavg[72]
Definition: wcs.h:1868
wcsprm::cd
double * cd
Definition: wcs.h:1839
WCSERR_BAD_COORD_TRANS
@ WCSERR_BAD_COORD_TRANS
Definition: wcs.h:1758
wcsprm::m_pc
double * m_pc
Definition: wcs.h:1923
wcsprm::trefpos
char trefpos[72]
Definition: wcs.h:1862
spcprm
Spectral transformation parameters.
Definition: spc.h:806
wcsprm::m_cperi
double * m_cperi
Definition: wcs.h:1930
wcsprm::ps
struct pscard * ps
Definition: wcs.h:1835
wcsprm::zsource
double zsource
Definition: wcs.h:1884
wcsprm::velangl
double velangl
Definition: wcs.h:1886
wcsprm::npv
int npv
Definition: wcs.h:1829
wcsprm::crval
double * crval
Definition: wcs.h:1818
wcsprm::colax
int * colax
Definition: wcs.h:1852
WCSERR_NON_SEPARABLE
@ WCSERR_NON_SEPARABLE
Definition: wcs.h:1770
wcsprm::specsys
char specsys[72]
Definition: wcs.h:1881
wtbarr
Extraction of coordinate lookup tables from BINTABLE.
Definition: getwcstab.h:169
wcsprm::m_crpix
double * m_crpix
Definition: wcs.h:1923
wcsprm::m_wtb
struct wtbarr * m_wtb
Definition: wcs.h:1933
auxprm::rsun_ref
double rsun_ref
Definition: wcs.h:1796
wcsprm::timrder
double timrder
Definition: wcs.h:1874
wcsprm::m_aux
struct auxprm * m_aux
Definition: wcs.h:1931
wcsprm::cname
char(* cname)[72]
Definition: wcs.h:1854
wcsprm::timedel
double timedel
Definition: wcs.h:1875
wcsprm::lattyp
char lattyp[8]
Definition: wcs.h:1902
wcsprm::alt
char alt[4]
Definition: wcs.h:1850
wcsset
int wcsset(struct wcsprm *wcs)
Setup routine for the wcsprm struct.
pscard::i
int i
Definition: wcs.h:1786
wcsprm::timsyer
double timsyer
Definition: wcs.h:1874
wcsprm::m_flag
int m_flag
Definition: wcs.h:1922
pvcard::i
int i
Definition: wcs.h:1776
wcs_errmsg_enum
wcs_errmsg_enum
Definition: wcs.h:1750
wcsprm::crpix
double * crpix
Definition: wcs.h:1815
wcsprm::flag
int flag
Definition: wcs.h:1810
WCSERR_BAD_PARAM
@ WCSERR_BAD_PARAM
Definition: wcs.h:1757
wcsprm::mjdend
double mjdend
Definition: wcs.h:1869
WCSERR_SUCCESS
@ WCSERR_SUCCESS
Definition: wcs.h:1751
wcsprm::tstart
double tstart
Definition: wcs.h:1871
wcsnpv
int wcsnpv(int n)
Memory allocation for PVi_ma.
wcsprm::m_cd
double * m_cd
Definition: wcs.h:1927
wcsprm::timeoffs
double timeoffs
Definition: wcs.h:1866
wcsprm::timeunit
char timeunit[72]
Definition: wcs.h:1863
wcsprm::restfrq
double restfrq
Definition: wcs.h:1826
wcsprm::types
int * types
Definition: wcs.h:1906
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.
wcsprt
int wcsprt(const struct wcsprm *wcs)
Print routine for the wcsprm struct.
WCSERR_BAD_CTYPE
@ WCSERR_BAD_CTYPE
Definition: wcs.h:1755
wcsprm
Coordinate transformation parameters.
Definition: wcs.h:1807
wcsprm::datebeg
char datebeg[72]
Definition: wcs.h:1868
wcsprm::latpole
double latpole
Definition: wcs.h:1824
wcsprm::lin
struct linprm lin
Definition: wcs.h:1908
wcsprm::tstop
double tstop
Definition: wcs.h:1871
auxprm::dsun_obs
double dsun_obs
Definition: wcs.h:1797
wcsprm::pv
struct pvcard * pv
Definition: wcs.h:1831
wcsprm::mjdbeg
double mjdbeg
Definition: wcs.h:1869
wcsprm::altlin
int altlin
Definition: wcs.h:1841
wcsprm::jepoch
double jepoch
Definition: wcs.h:1870
wcsprm::cperi
double * cperi
Definition: wcs.h:1858
wcsprm::obsgeo
double obsgeo[6]
Definition: wcs.h:1877
wcsprm::m_ps
struct pscard * m_ps
Definition: wcs.h:1926
auxprm::hglt_obs
double hglt_obs
Definition: wcs.h:1800
WCSERR_BAD_SUBIMAGE
@ WCSERR_BAD_SUBIMAGE
Definition: wcs.h:1769
wcsprm::dateend
char dateend[72]
Definition: wcs.h:1868
wcsprm::m_crder
double * m_crder
Definition: wcs.h:1930
wcsprm::mjdavg
double mjdavg
Definition: wcs.h:1869
wcsprm::telapse
double telapse
Definition: wcs.h:1872
wcsauxi
int wcsauxi(int alloc, struct wcsprm *wcs)
Default constructor for the auxprm struct.
wcsprm::err
struct wcserr * err
Definition: wcs.h:1918
wcsprm::restwav
double restwav
Definition: wcs.h:1827
WCSERR_BAD_WORLD_COORD
@ WCSERR_BAD_WORLD_COORD
Definition: wcs.h:1766
WCSERR_NO_SOLUTION
@ WCSERR_NO_SOLUTION
Definition: wcs.h:1767
tabprm
Tabular transformation parameters.
Definition: tab.h:545
wcssub
int wcssub(int alloc, const struct wcsprm *wcssrc, int *nsub, int axes[], struct wcsprm *wcsdst)
Subimage extraction routine for the wcsprm struct.
wcsprm::spc
struct spcprm spc
Definition: wcs.h:1910
celprm
Celestial transformation parameters.
Definition: cel.h:397
wcsprm::pc
double * pc
Definition: wcs.h:1816
wcsprm::mjdobs
double mjdobs
Definition: wcs.h:1869
wcsprm::ctype
char(* ctype)[72]
Definition: wcs.h:1821
pvcard::m
int m
Definition: wcs.h:1777
wcsprm::m_csyer
double * m_csyer
Definition: wcs.h:1930
wcsprm::wcsname
char wcsname[72]
Definition: wcs.h:1860
wcsprm::radesys
char radesys[72]
Definition: wcs.h:1879
wcsprm::naxis
int naxis
Definition: wcs.h:1814
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.
pvcard::value
double value
Definition: wcs.h:1778
wcsbchk
int wcsbchk(struct wcsprm *wcs, int bounds)
Enable/disable bounds checking.
wcsprm::tab
struct tabprm * tab
Definition: wcs.h:1896
wcsprm::xposure
double xposure
Definition: wcs.h:1872
wcsprm::colnum
int colnum
Definition: wcs.h:1851
wcsperr
int wcsperr(const struct wcsprm *wcs, const char *prefix)
Print error messages from a wcsprm struct.
wcsprm::m_naxis
int m_naxis
Definition: wcs.h:1922
wcsprm::plephem
char plephem[72]
Definition: wcs.h:1862
wcsprm::cunit
char(* cunit)[72]
Definition: wcs.h:1820
wcsprm::npvmax
int npvmax
Definition: wcs.h:1830
wcsprm::m_czphs
double * m_czphs
Definition: wcs.h:1930
wcsprm::aux
struct auxprm * aux
Definition: wcs.h:1890
linprm
Linear transformation parameters.
Definition: lin.h:630
wtbarr::i
int i
Definition: getwcstab.h:170
WCSERR_BAD_WORLD
@ WCSERR_BAD_WORLD
Definition: wcs.h:1764
wcsprm::npsmax
int npsmax
Definition: wcs.h:1834
auxprm::hgln_obs
double hgln_obs
Definition: wcs.h:1799
wcsprm::m_colax
int * m_colax
Definition: wcs.h:1928
wcsprm::bepoch
double bepoch
Definition: wcs.h:1870
pvcard
Store for PVi_ma keyrecords.
Definition: wcs.h:1775
wcsprm::crder
double * crder
Definition: wcs.h:1855
wcserr
Error message handling.
Definition: wcserr.h:222
wcsprm::equinox
double equinox
Definition: wcs.h:1880
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.
wcsnps
int wcsnps(int n)
Memory allocation for PSi_ma.
wcsprm::csyer
double * csyer
Definition: wcs.h:1856
wcsfree
int wcsfree(struct wcsprm *wcs)
Destructor for the wcsprm struct.
pscard
Store for PSi_ma keyrecords.
Definition: wcs.h:1785
wcs_errmsg
const char * wcs_errmsg[]
Status return messages.
wcsprm::lonpole
double lonpole
Definition: wcs.h:1823
wcsprm::m_cdelt
double * m_cdelt
Definition: wcs.h:1923
wcsprm::velosys
double velosys
Definition: wcs.h:1883
wcsprm::cdelt
double * cdelt
Definition: wcs.h:1817
wcsprm::m_cunit
char(* m_cunit)[72]
Definition: wcs.h:1924
wcsprm::ssyssrc
char ssyssrc[72]
Definition: wcs.h:1885
wcsprm::wtb
struct wtbarr * wtb
Definition: wcs.h:1897
WCSERR_MEMORY
@ WCSERR_MEMORY
Definition: wcs.h:1753
lin.h
wcsprm::velref
int velref
Definition: wcs.h:1845
wcssptr
int wcssptr(struct wcsprm *wcs, int *i, char ctype[9])
Spectral axis translation.
wcsprm::m_crval
double * m_crval
Definition: wcs.h:1923
wcsprm::ntab
int ntab
Definition: wcs.h:1894
WCSERR_SINGULAR_MTX
@ WCSERR_SINGULAR_MTX
Definition: wcs.h:1754
wcsprm::czphs
double * czphs
Definition: wcs.h:1857
wcsprm::mjdref
double mjdref[2]
Definition: wcs.h:1865
wcsprm::nwtb
int nwtb
Definition: wcs.h:1895
wcsini
int wcsini(int alloc, int naxis, struct wcsprm *wcs)
Default constructor for the wcsprm struct.
auxprm
Additional auxiliary parameters.
Definition: wcs.h:1795