/*============================================================================ WCSLIB 6.2 - an implementation of the FITS WCS standard. Copyright (C) 1995-2018, Mark Calabretta This file is part of WCSLIB. WCSLIB is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. WCSLIB is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with WCSLIB. If not, see http://www.gnu.org/licenses. Direct correspondence concerning WCSLIB to mark@calabretta.id.au Author: Mark Calabretta, Australia Telescope National Facility, CSIRO. http://www.atnf.csiro.au/people/Mark.Calabretta $Id: wcsfix.h,v 6.2 2018/10/20 10:03:13 mcalabre Exp $ *============================================================================= * * WCSLIB 6.2 - C routines that implement the FITS World Coordinate System * (WCS) standard. Refer to the README file provided with WCSLIB for an * overview of the library. * * * Summary of the wcsfix routines * ------------------------------ * Routines in this suite identify and translate various forms of construct * known to occur in FITS headers that violate the FITS World Coordinate System * (WCS) standard described in * = "Representations of world coordinates in FITS", = Greisen, E.W., & Calabretta, M.R. 2002, A&A, 395, 1061 (WCS Paper I) = = "Representations of celestial coordinates in FITS", = Calabretta, M.R., & Greisen, E.W. 2002, A&A, 395, 1077 (WCS Paper II) = = "Representations of spectral coordinates in FITS", = Greisen, E.W., Calabretta, M.R., Valdes, F.G., & Allen, S.L. = 2006, A&A, 446, 747 (WCS Paper III) = = "Representations of time coordinates in FITS - = Time and relative dimension in space", = Rots, A.H., Bunclark, P.S., Calabretta, M.R., Allen, S.L., = Manchester, R.N., & Thompson, W.T. 2015, A&A, 574, A36 (WCS Paper VII) * * Repairs effected by these routines range from the translation of * non-standard values for standard WCS keywords, to the repair of malformed * coordinate representations. Some routines are also provided to check the * consistency of pairs of keyvalues that define the same measure in two * different ways, for example, as a date and an MJD. * * Non-standard keyvalues: * ----------------------- * AIPS-convention celestial projection types, NCP and GLS, and spectral * types, 'FREQ-LSR', 'FELO-HEL', etc., set in CTYPEia are translated * on-the-fly by wcsset() but without modifying the relevant ctype[], pv[] or * specsys members of the wcsprm struct. That is, only the information * extracted from ctype[] is translated when wcsset() fills in wcsprm::cel * (celprm struct) or wcsprm::spc (spcprm struct). * * On the other hand, these routines do change the values of wcsprm::ctype[], * wcsprm::pv[], wcsprm::specsys and other wcsprm struct members as * appropriate to produce the same result as if the FITS header itself had * been translated. * * Auxiliary WCS header information not used directly by WCSLIB may also be * translated. For example, the older DATE-OBS date format (wcsprm::dateobs) * is recast to year-2000 standard form, and MJD-OBS (wcsprm::mjdobs) will be * deduced from it if not already set. * * Certain combinations of keyvalues that result in malformed coordinate * systems, as described in Sect. 7.3.4 of Paper I, may also be repaired. * These are handled by cylfix(). * * Non-standard keywords: * ---------------------- * The AIPS-convention CROTAn keywords are recognized as quasi-standard * and as such are accomodated by wcsprm::crota[] and translated to * wcsprm::pc[][] by wcsset(). These are not dealt with here, nor are any * other non-standard keywords since these routines work only on the contents * of a wcsprm struct and do not deal with FITS headers per se. In * particular, they do not identify or translate CD00i00j, PC00i00j, PROJPn, * EPOCH, VELREF or VSOURCEa keywords; this may be done by the FITS WCS * header parser supplied with WCSLIB, refer to wcshdr.h. * * wcsfix() and wcsfixi() apply all of the corrections handled by the following * specific functions which may also be invoked separately: * * - cdfix(): Sets the diagonal element of the CDi_ja matrix to 1.0 if all * CDi_ja keywords associated with a particular axis are omitted. * * - datfix(): recast an older DATE-OBS date format in dateobs to year-2000 * standard form. * * Derive mjdobs from dateobs if not already set. Alternatively, if mjdobs * is set and dateobs isn't, then derive dateobs from it. If both are set, * then check consistency. Likewise for datebeg and mjdbeg; dateavg and * mjdavg; and dateend and mjdend. * * - obsfix(): if only one half of obsgeo[] is set, then derive the other * half from it. If both halves are set, then check consistency. * * - unitfix(): translate some commonly used but non-standard unit strings in * the CUNITia keyvalues, e.g. 'DEG' -> 'deg'. * * - spcfix(): translate AIPS-convention spectral types, 'FREQ-LSR', * 'FELO-HEL', etc., in ctype[] as set from CTYPEia. * * - celfix(): translate AIPS-convention celestial projection types, NCP and * GLS, in ctype[] as set from CTYPEia. * * - cylfix(): fixes WCS keyvalues for malformed cylindrical projections that * suffer from the problem described in Sect. 7.3.4 of Paper I. * * * wcsfix() - Translate a non-standard WCS struct * ---------------------------------------------- * wcsfix() is identical to wcsfixi(), but lacks the info argument. * * * wcsfixi() - Translate a non-standard WCS struct * ----------------------------------------------- * wcsfixi() applies all of the corrections handled separately by cdfix(), * datfix(), obsfix(), unitfix(), spcfix(), celfix(), and cylfix(). * * Given: * ctrl int Do potentially unsafe translations of non-standard * unit strings as described in the usage notes to * wcsutrn(). * * naxis const int [] * Image axis lengths. If this array pointer is set to * zero then cylfix() will not be invoked. * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. * * Returned: * stat int [NWCSFIX] * Status returns from each of the functions. Use the * preprocessor macros NWCSFIX to dimension this vector * and CDFIX, DATFIX, OBSFIX, UNITFIX, SPCFIX, CELFIX, * and CYLFIX to access its elements. A status value * of -2 is set for functions that were not invoked. * * info struct wcserr [NWCSFIX] * Status messages from each of the functions. Use the * preprocessor macros NWCSFIX to dimension this vector * and CDFIX, DATFIX, OBSFIX, UNITFIX, SPCFIX, CELFIX, * and CYLFIX to access its elements. * * Function return value: * int Status return value: * 0: Success. * 1: One or more of the translation functions * returned an error. * * * cdfix() - Fix erroneously omitted CDi_ja keywords * ------------------------------------------------- * cdfix() sets the diagonal element of the CDi_ja matrix to unity if all * CDi_ja keywords associated with a given axis were omitted. According to * Paper I, if any CDi_ja keywords at all are given in a FITS header then those * not given default to zero. This results in a singular matrix with an * intersecting row and column of zeros. * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. * * Function return value: * int Status return value: * -1: No change required (not an error). * 0: Success. * 1: Null wcsprm pointer passed. * * * datfix() - Translate DATE-OBS and derive MJD-OBS or vice versa * -------------------------------------------------------------- * datfix() translates the old DATE-OBS date format set in wcsprm::dateobs to * year-2000 standard form (yyyy-mm-ddThh:mm:ss). * * datfix() derives wcsprm::mjdobs from wcsprm::datobs if not already set. * Alternatively, if mjdobs is set and dateobs isn't, then it derives dateobs * from it. If both are set but disagree by more than 0.001 day (86.4 seconds) * then status 5 is returned. Likewise for wcsprm::datebeg and wcsprm::mjdbeg; * wcsprm::dateavg and wcsprm::mjdavg; and wcsprm::dateend and wcsprm::mjdend. * * If neither dateobs nor mjdobs are set, but wcsprm::jepoch (primarily) or * wcsprm::bepoch is, then both are derived from it. If jepoch and/or bepoch * are set but disagree with dateobs or mjdobs by more than 0.000002 year * (63.2 seconds), an informative message is produced. * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. * wcsprm::dateobs and/or wcsprm::mjdobs may be changed. * wcsprm::datebeg and/or wcsprm::mjdbeg may be changed. * wcsprm::dateavg and/or wcsprm::mjdavg may be changed. * wcsprm::dateend and/or wcsprm::mjdend may be changed. * * Function return value: * int Status return value: * -1: No change required (not an error). * 0: Success. * 1: Null wcsprm pointer passed. * 5: Invalid parameter value. * * For returns > 1, a detailed error message is set in * wcsprm::err if enabled, see wcserr_enable(). * * Notes: * The MJD algorithms used by datfix() are from D.A. Hatcher, 1984, QJRAS, * 25, 53-55, as modified by P.T. Wallace for use in SLALIB subroutines CLDJ * and DJCL. * * * obsfix() - complete the OBSGEO-[XYZLBH] vector of observatory coordinates * ------------------------------------------------------------------------- * obsfix() completes the wcsprm::obsgeo vector of observatory coordinates. * That is, if only the (x,y,z) Cartesian coordinate triplet or the (l,b,h) * geodetic coordinate triplet are set, then it derives the other triplet from * it. If both triplets are set, then it checks for consistency at the level * of 1 metre. * * Given: * ctrl int Flag that controls behaviour if one triplet is * defined and the other is only partially defined: * 0: Reset only the undefined elements of an * incomplete coordinate triplet. * 1: Reset all elements of an incomplete triplet. * 2: Don't make any changes, check for consistency * only. Returns an error if either of the two * triplets is incomplete. * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. * wcsprm::obsgeo may be changed. * * Function return value: * int Status return value: * -1: No change required (not an error). * 0: Success. * 1: Null wcsprm pointer passed. * 5: Invalid parameter value. * * For returns > 1, a detailed error message is set in * wcsprm::err if enabled, see wcserr_enable(). * * Notes: * 1: While the International Terrestrial Reference System (ITRS) is based * solely on Cartesian coordinates, it recommends the use of the GRS80 * ellipsoid in converting to geodetic coordinates. However, while WCS * Paper III recommends ITRS Cartesian coordinates, Paper VII prescribes * the use of the IAU(1976) ellipsoid for geodetic coordinates, and * consequently that is what is used here. * * 2: For reference, parameters of commonly used global reference ellipsoids: * = a (m) 1/f Standard = --------- ------------- -------------------------------- = 6378140 298.2577 IAU(1976) = 6378137 298.257222101 GRS80 = 6378137 298.257223563 WGS84 = 6378136 298.257 IERS(1989) = 6378136.6 298.25642 IERS(2003,2010), IAU(2009/2012) * * where f = (a - b) / a is the flattening, and a and b are the semi-major * and semi-minor radii in metres. * * 3: The transformation from geodetic (lng,lat,hgt) to Cartesian (x,y,z) is * = x = (n + hgt)*coslng*coslat, = y = (n + hgt)*sinlng*coslat, = z = (n*(1.0 - e^2) + hgt)*sinlat, * * where the "prime vertical radius", n, is a function of latitude * = n = a / sqrt(1 - (e*sinlat)^2), * * and a, the equatorial radius, and e^2 = (2 - f)*f, the (first) * eccentricity of the ellipsoid, are constants. obsfix() inverts these * iteratively by writing * = x = rho*coslng*coslat, = y = rho*sinlng*coslat, = zeta = rho*sinlat, * * where * = rho = n + hgt, = = sqrt(x^2 + y^2 + zeta^2), = zeta = z / (1 - n*e^2/rho), * * and iterating over the value of zeta. Since e is small, a good first * approximation is given by zeta = z. * * * unitfix() - Correct aberrant CUNITia keyvalues * ---------------------------------------------- * unitfix() applies wcsutrn() to translate non-standard CUNITia keyvalues, * e.g. 'DEG' -> 'deg', also stripping off unnecessary whitespace. * * Given: * ctrl int Do potentially unsafe translations described in the * usage notes to wcsutrn(). * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. * * Function return value: * int Status return value: * -1: No change required (not an error). * 0: Success (an alias was applied). * 1: Null wcsprm pointer passed. * * When units are translated (i.e. status 0), status -2 * is set in the wcserr struct to allow an informative * message to be returned. * * * spcfix() - Translate AIPS-convention spectral types * --------------------------------------------------- * spcfix() translates AIPS-convention spectral coordinate types, * '{FREQ,FELO,VELO}-{LSR,HEL,OBS}' (e.g. 'FREQ-OBS', 'FELO-HEL', 'VELO-LSR') * set in wcsprm::ctype[], subject to VELREF set in wcsprm::velref. * * Note that if wcs::specsys is already set then it will not be overridden. * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. wcsprm::ctype[] * and/or wcsprm::specsys may be changed. * * Function return value: * int Status return value: * -1: No change required (not an error). * 0: Success. * 1: Null wcsprm pointer passed. * 2: Memory allocation failed. * 3: Linear transformation matrix is singular. * 4: Inconsistent or unrecognized coordinate axis * types. * 5: Invalid parameter value. * 6: Invalid coordinate transformation parameters. * 7: Ill-conditioned coordinate transformation * parameters. * * For returns > 1, a detailed error message is set in * wcsprm::err if enabled, see wcserr_enable(). * * * celfix() - Translate AIPS-convention celestial projection types * --------------------------------------------------------------- * celfix() translates AIPS-convention celestial projection types, NCP and * GLS, set in the ctype[] member of the wcsprm struct. * * Two additional pv[] keyvalues are created when translating NCP, and three * are created when translating GLS with non-zero reference point. If the pv[] * array was initially allocated by wcsini() then the array will be expanded if * necessary. Otherwise, error 2 will be returned if sufficient empty slots * are not already available for use. * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. wcsprm::ctype[] * and/or wcsprm::pv[] may be changed. * * Function return value: * int Status return value: * -1: No change required (not an error). * 0: Success. * 1: Null wcsprm pointer passed. * 2: Memory allocation failed. * 3: Linear transformation matrix is singular. * 4: Inconsistent or unrecognized coordinate axis * types. * 5: Invalid parameter value. * 6: Invalid coordinate transformation parameters. * 7: Ill-conditioned coordinate transformation * parameters. * * For returns > 1, a detailed error message is set in * wcsprm::err if enabled, see wcserr_enable(). * * * cylfix() - Fix malformed cylindrical projections * ------------------------------------------------ * cylfix() fixes WCS keyvalues for malformed cylindrical projections that * suffer from the problem described in Sect. 7.3.4 of Paper I. * * Given: * naxis const int [] * Image axis lengths. * * Given and returned: * wcs struct wcsprm* * Coordinate transformation parameters. * * Function return value: * int Status return value: * -1: No change required (not an error). * 0: Success. * 1: Null wcsprm pointer passed. * 2: Memory allocation failed. * 3: Linear transformation matrix is singular. * 4: Inconsistent or unrecognized coordinate axis * types. * 5: Invalid parameter value. * 6: Invalid coordinate transformation parameters. * 7: Ill-conditioned coordinate transformation * parameters. * 8: All of the corner pixel coordinates are invalid. * 9: Could not determine reference pixel coordinate. * 10: Could not determine reference pixel value. * * For returns > 1, a detailed error message is set in * wcsprm::err if enabled, see wcserr_enable(). * * * Global variable: const char *wcsfix_errmsg[] - Status return messages * --------------------------------------------------------------------- * Error messages to match the status value returned from each function. * *===========================================================================*/ #ifndef WCSLIB_WCSFIX #define WCSLIB_WCSFIX #include "wcs.h" #include "wcserr.h" #ifdef __cplusplus extern "C" { #endif #define CDFIX 0 #define DATFIX 1 #define OBSFIX 2 #define UNITFIX 3 #define SPCFIX 4 #define CELFIX 5 #define CYLFIX 6 #define NWCSFIX 7 extern const char *wcsfix_errmsg[]; #define cylfix_errmsg wcsfix_errmsg enum wcsfix_errmsg_enum { FIXERR_OBSGEO_FIX = -5, /* Observatory coordinates amended. */ FIXERR_DATE_FIX = -4, /* Date string reformatted. */ FIXERR_SPC_UPDATE = -3, /* Spectral axis type modified. */ FIXERR_UNITS_ALIAS = -2, /* Units alias translation. */ FIXERR_NO_CHANGE = -1, /* No change. */ FIXERR_SUCCESS = 0, /* Success. */ FIXERR_NULL_POINTER = 1, /* Null wcsprm pointer passed. */ FIXERR_MEMORY = 2, /* Memory allocation failed. */ FIXERR_SINGULAR_MTX = 3, /* Linear transformation matrix is singular. */ FIXERR_BAD_CTYPE = 4, /* Inconsistent or unrecognized coordinate axis types. */ FIXERR_BAD_PARAM = 5, /* Invalid parameter value. */ FIXERR_BAD_COORD_TRANS = 6, /* Invalid coordinate transformation parameters. */ FIXERR_ILL_COORD_TRANS = 7, /* Ill-conditioned coordinate transformation parameters. */ FIXERR_BAD_CORNER_PIX = 8, /* All of the corner pixel coordinates are invalid. */ FIXERR_NO_REF_PIX_COORD = 9, /* Could not determine reference pixel coordinate. */ FIXERR_NO_REF_PIX_VAL = 10 /* Could not determine reference pixel value. */ }; int wcsfix(int ctrl, const int naxis[], struct wcsprm *wcs, int stat[]); int wcsfixi(int ctrl, const int naxis[], struct wcsprm *wcs, int stat[], struct wcserr info[]); int cdfix(struct wcsprm *wcs); int datfix(struct wcsprm *wcs); int obsfix(int ctrl, struct wcsprm *wcs); int unitfix(int ctrl, struct wcsprm *wcs); int spcfix(struct wcsprm *wcs); int celfix(struct wcsprm *wcs); int cylfix(const int naxis[], struct wcsprm *wcs); #ifdef __cplusplus } #endif #endif /* WCSLIB_WCSFIX */