#from .. pywcs.sip import SIP from pywcs import WCS import pyfits import instruments #from .. distortion import models from updatewcs.distortion import models import numpy as N from pytools import fileutil from pytools.fileutil import DEGTORAD, RADTODEG #from .. mappings import inst_mappings, ins_spec_kw, DEGTORAD, RADTODEG, basic_wcs import mappings from mappings import inst_mappings, ins_spec_kw from mappings import basic_wcs, prim_hdr_kw __docformat__ = 'restructuredtext' __version__ = '0.3' class HSTWCS(WCS): """ Purpose ======= Create a WCS object based on the instrument. It has all basic WCS kw as attribbutes (set by pywcs). It also uses the primary and extension header to define instrument specific attributes needed by the correction classes. """ def __init__(self, fobj=None, ext=None, instrument=None, detector=None): """ :Parameters: `fobj`: string or PyFITS HDUList object or None a file name, e.g j9irw4b1q_flt.fits a fully qualified filename[EXTNAME,EXTNUM], e.g. j9irw4b1q_flt.fits[sci,1] a pyfits file object, e.g pyfits.open('j9irw4b1q_flt.fits') `ext`: int or None extension number if ext==None, it is assumed the data is in the primary hdu `instrument`: string one of 'ACS', 'NICMOS', 'WFPC2', 'STIS', 'WFC3' `detector`: string for example 'WFC' If instrument and detector parameters are give, a default HSTWCS instrument is created. """ self.inst_kw = ins_spec_kw if instrument == None: filename, hdr0, ehdr = self.parseInput(fobj=fobj, ext=ext) self.filename = filename WCS.__init__(self, ehdr, fobj=fobj) self.setHDR0kw(hdr0, ehdr) self.setInstrSpecKw(hdr0, ehdr) self.setPscale() self.setOrient() self.readIDCCoeffs(ehdr) extname = ehdr.get('EXTNAME', "") extnum = ehdr.get('EXTVER', None) self.extname = (extname, extnum) else: # create a default HSTWCS object based on #instrument and detector parameters self.instrument = instrument self.detector = detector self.setInstrSpecKw() def parseInput(self, fobj=None, ext=None): if isinstance(fobj, str): # create an HSTWCS object from a filename if ext != None: filename = fobj extnum = ext elif ext == None: filename, extname = fileutil.parseFilename(fobj) if extname == None: #data may be in the primary array extnum = 0 else: extnum = fileutil.parseExtn(extname) hdr0 = pyfits.getheader(filename) try: ehdr = pyfits.getheader(filename, ext=extnum) except IndexError: print 'Unable to get extension %d. /n' % ext elif isinstance(fobj, pyfits.HDUList): if ext == None: extnum = 0 else: extnum = ext ehdr = fobj[extnum].header hdr0 = fobj[0].header filename = hdr0.get('FILENAME', "") return filename, hdr0, ehdr def setHDR0kw(self, primhdr, ehdr): # Set attributes from kw defined in the primary header. self.instrument = primhdr.get('INSTRUME', None) self.offtab = primhdr.get('OFFTAB', None) self.idctab = primhdr.get('IDCTAB', None) self.date_obs = primhdr.get('DATE-OBS', None) self.ra_targ = primhdr.get('RA_TARG', None) self.dec_targ = primhdr.get('DEC_TARG', None) #self.detector = primhdr.get('DETECTOR', None) try: self.pav3 = primhdr['PA_V3'] except KeyError: print 'Kw PA_V3 not found in primary header.' print 'This is typical for some old files. Please retrieve the files fromthe archive again.' print 'Quitting ...' raise def readIDCCoeffs(self, header): """ Reads in first order IDCTAB coefficients if present in the header """ coeffs = ['ocx10', 'ocx11', 'ocy10', 'ocy11', 'idcscale'] for c in coeffs: self.__setattr__(c, header.get(c, None)) def setInstrSpecKw(self, prim_hdr=None, ext_hdr=None): # Based on the instrument kw creates an instalnce of an instrument WCS class # and sets attributes from instrument specific kw if self.instrument in inst_mappings.keys(): inst_kl = inst_mappings[self.instrument] inst_kl = instruments.__dict__[inst_kl] insobj = inst_kl(prim_hdr, ext_hdr) for key in self.inst_kw: try: self.__setattr__(key, insobj.__getattribute__(key)) except AttributeError: # Some of the instrument's attributes are recorded in the primary header and # were already set, (e.g. 'DETECTOR'), the code below is a check for that case. if not self.__getattribute__(key): raise else: pass else: raise KeyError, "Unsupported instrument - %s" %self.instrument def setPscale(self): # Calculates the plate scale from the cd matrix # this may not be needed now and shoufl probably be done after all # corrections cd11 = self.wcs.cd[0][0] cd21 = self.wcs.cd[1][0] self.pscale = N.sqrt(N.power(cd11,2)+N.power(cd21,2)) * 3600. def setOrient(self): # Recompute ORIENTAT cd12 = self.wcs.cd[0][1] cd22 = self.wcs.cd[1][1] self.orientat = RADTODEG(N.arctan2(cd12,cd22)) def updatePscale(self, pscale): """Given a plate scale, update the CD matrix""" old_pscale = self.pscale self.pscale = pscale self.wcs.cd = self.wcs.cd * pscale/old_pscale self.naxis1 = self.naxis1 * old_pscale/ pscale self.naxis2 = self.naxis2 * old_pscale/ pscale self.wcs.crpix = self.wcs.crpix *old_pscale/pscale def updateOrient(self, orient): """Given n angle update the CD matrix""" if self.orientat == orient: return old_orient = self.orientat self.orientat = orient angle = fileutil.DEGTORAD(orient) cd11 = -N.cos(angle) cd12 = N.sin(angle) cd21 = cd12 cd22 = -cd11 cdmat = N.array([[cd11, cd12],[cd21,cd22]]) self.wcs.cd = cdmat * self.pscale/3600 def readModel(self, update=False, header=None): """ Purpose ======= Read distortion model from idc table. Save some of the information as kw needed for interpreting the distortion If header is provided and update is True, some IDC model kw will be recorded in the header. """ if self.idctab == None or self.date_obs == None: print 'idctab or date_obs not available\n' self.idcmodel = None return if self.filter1 ==None and self.filter2 == None: 'No filter information available\n' self.idcmodel = None return self.idcmodel = models.IDCModel(self.idctab, chip=self.chip, direction='forward', date=self.date_obs, filter1=self.filter1, filter2=self.filter2, offtab=self.offtab, binned=self.binned) if update: if header==None: print 'Update header with IDC model kw requested but header was not provided\n.' return else: self.updatehdr(header) def restore(self, header=None): """ Restore a WCS archive in memory and update the WCS object. Restored are the basic WCS kw as well as pscale and orient. """ from pywcs import Wcsprm backup = {} if header == None: print 'Need a valid header in order to restore archive\n' return for k in basic_wcs: try: nkw = ('O'+k)[:7] backup[k] = header[nkw] except KeyError: pass if backup == {}: print 'No archive was found\n' return cdl=pyfits.CardList() for item in backup.items(): card = pyfits.Card(key=item[0], value=item[1]) cdl.append(card) h = pyfits.Header(cdl) wprm = Wcsprm("".join([str(x) for x in h.ascardlist()])) self.wcs = wprm self.setPscale() self.setOrient() def updatehdr(self, ext_hdr, newkeywords=None): #kw2add : OCX10, OCX11, OCY10, OCY11 # record the model in the header for use by pydrizzle ext_hdr.update('OCX10', self.idcmodel.cx[1,0]) ext_hdr.update('OCX11', self.idcmodel.cx[1,1]) ext_hdr.update('OCY10', self.idcmodel.cy[1,0]) ext_hdr.update('OCY11', self.idcmodel.cy[1,1]) ext_hdr.update('IDCSCALE', self.idcmodel.refpix['PSCALE']) ext_hdr.update('IDCTHETA', self.idcmodel.refpix['THETA']) ext_hdr.update('IDCXREF', self.idcmodel.refpix['XREF']) ext_hdr.update('IDCYREF', self.idcmodel.refpix['YREF']) ext_hdr.update('IDCV2REF', self.idcmodel.refpix['V2REF']) ext_hdr.update('IDCV3REF', self.idcmodel.refpix['V3REF']) def help(): print 'How to create an HSTWCS object:\n\n' print """ \ 1. Using a pyfits HDUList object and an extension number \n Example:\n fobj = pyfits.open('some_file.fits')\n w = wcsutil.HSTWCS(fobj, 3)\n\n 2. Create an HSTWCS object using a qualified file name. \n Example:\n w = wcsutil.HSTWCS('j9irw4b1q_flt.fits[sci,1]')\n\n 3. Create an HSTWCS object using a file name and an extension number. \n Example:\n w = wcsutil.HSTWCS('j9irw4b1q_flt.fits', ext=2)\n\n 4. Create a template HSTWCS object for an instrument/detector combination.]n Example:\n w = wcsutil.HSTWCS(instrument='ACS', detector='WFC'\n\n """