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Diffstat (limited to 'wcsutil/hstwcs.py')
| -rw-r--r-- | wcsutil/hstwcs.py | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/wcsutil/hstwcs.py b/wcsutil/hstwcs.py new file mode 100644 index 0000000..e543550 --- /dev/null +++ b/wcsutil/hstwcs.py @@ -0,0 +1,344 @@ +from __future__ import division # confidence high + +import os.path +from pywcs import WCS +import pyfits +import instruments +from stwcs.distortion import models, coeff_converter +import altwcs +import numpy as np +from pytools import fileutil +from pytools.fileutil import DEGTORAD, RADTODEG + +import mappings +from mappings import inst_mappings, ins_spec_kw +from mappings import basic_wcs + + +__docformat__ = 'restructuredtext' +__version__ = '0.4' + +class HSTWCS(WCS): + """ + Purpose + ======= + Create a WCS object based on the instrument. + It has all basic WCS kw as attributes (set by pywcs). + It also uses the primary and extension header to define + instrument specific attributes. + """ + def __init__(self, fobj='DEFAULT', ext=None, minerr=0.0, wcskey=" "): + """ + :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'), in which case the + user is responsible for closing the file object. + `ext`: int or None + extension number + if ext==None, it is assumed the data is in the primary hdu + + `minerr`: float + minimum value a distortion correction must have in order to be applied. + If CPERRja, CQERRja are smaller than minerr, the corersponding + distortion is not applied. + """ + + self.inst_kw = ins_spec_kw + self.minerr = minerr + self.wcskey = wcskey + + if fobj != 'DEFAULT': + filename, hdr0, ehdr, phdu = self.parseInput(f=fobj, ext=ext) + self.filename = filename + self.instrument = hdr0['INSTRUME'] + + WCS.__init__(self, ehdr, fobj=phdu, minerr=self.minerr, key=self.wcskey) + # If input was a pyfits HDUList object, it's the user's + # responsibility to close it, otherwise, it's closed here. + if not isinstance(fobj, pyfits.HDUList): + phdu.close() + self.setInstrSpecKw(hdr0, ehdr) + self.readIDCCoeffs(ehdr) + extname = ehdr.get('EXTNAME', "") + extnum = ehdr.get('EXTVER', None) + self.extname = (extname, extnum) + else: + # create a default HSTWCS object + self.instrument = 'DEFAULT' + WCS.__init__(self, minerr=self.minerr, key=self.wcskey) + self.wcs.cd = np.array([[1.0, 0.0], [0.0, 1.0]], np.double) + self.wcs.crval = np.zeros((self.naxis,), np.double) + self.wcs.crpix = np.zeros((self.naxis,), np.double) + self.wcs.set() + self.setInstrSpecKw() + self.setPscale() + self.setOrient() + + def parseInput(self, f=None, ext=None): + if isinstance(f, str): + # create an HSTWCS object from a filename + + if ext != None: + filename = f + if isinstance(ext,tuple): + if ext[0] == '': + extnum = ext[1] # handle ext=('',1) + else: + extnum = ext + else: + extnum = int(ext) + elif ext == None: + filename, ext = fileutil.parseFilename(f) + ext = fileutil.parseExtn(ext) + if ext[0] == '': + extnum = int(ext[1]) #handle ext=('',extnum) + else: + extnum = ext + phdu = pyfits.open(filename) + hdr0 = pyfits.getheader(filename) + try: + ehdr = pyfits.getheader(filename, ext=extnum) + except (IndexError,KeyError): + print 'Unable to get extension.', extnum + raise + + elif isinstance(f, pyfits.HDUList): + phdu = f + if ext == None: + extnum = 0 + else: + extnum = ext + ehdr = f[extnum].header + hdr0 = f[0].header + filename = hdr0.get('FILENAME', "") + + return filename, hdr0, ehdr, phdu + + + 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 + + cd11 = self.wcs.cd[0][0] + cd21 = self.wcs.cd[1][0] + self.pscale = np.sqrt(np.power(cd11,2)+np.power(cd21,2)) * 3600. + + def setOrient(self): + # Recompute ORIENTAT + cd12 = self.wcs.cd[0][1] + cd22 = self.wcs.cd[1][1] + self.orientat = RADTODEG(np.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 = -np.cos(angle) + cd12 = np.sin(angle) + cd21 = cd12 + cd22 = -cd11 + cdmat = np.array([[cd11, cd12],[cd21,cd22]]) + self.wcs.cd = cdmat * self.pscale/3600 + self.wcs.set() + + + def readModel(self, update=False, header=None): + """ + Reads distortion model from IDCTAB. + If IDCTAB is not found ('N/A', "", or not found on disk), then + if SIP coefficients and first order IDCTAb coefficients are present + in the header, restore the idcmodel from the header. + If not - assign None to self.idcmodel. + """ + + if self.idctab == None or self.idctab == ' ': + #Keyword idctab is not present in header - check for sip coefficients + if header.has_key('IDCSCALE'): + self._readModelFromHeader(header) + else: + print "Distortion model is not available: IDCTAB=None\n" + self.idcmodel = None + elif not os.path.exists(fileutil.osfn(self.idctab)): + if header.has_key('IDCSCALE'): + self._readModelFromHeader(header) + else: + print 'Distortion model is not available: IDCTAB file %s not found\n' % self.idctab + self.idcmodel = None + else: + self._readModelFromIDCTAB(header=header, update=update) + + def _readModelFromHeader(self, header): + # Recreate idc model from SIP coefficients and header kw + print 'Restoring IDC model from SIP coefficients\n' + model = models.GeometryModel() + cx, cy = coeff_converter.sip2idc(self) + model.cx = cx + model.cy = cy + model.name = "sip" + model.norder = header['A_ORDER'] + + refpix = {} + refpix['XREF'] = header['IDCXREF'] + refpix['YREF'] = header['IDCYREF'] + refpix['PSCALE'] = header['IDCSCALE'] + refpix['V2REF'] = header['IDCV2REF'] + refpix['V3REF'] = header['IDCV3REF'] + refpix['THETA'] = header['IDCTHETA'] + model.refpix = refpix + + self.idcmodel = model + + + def _readModelFromIDCTAB(self, header=None, update=False): + """ + 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.date_obs == None: + print '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.' + else: + self._updatehdr(header) + + def wcs2header(self, sip2hdr=False): + """ + Create a pyfits.Header object from all WCS keywords, + including the SIP coefficients. + """ + h = self.to_header() + if self.wcs.has_cd(): + h = pc2cd(h) + + if sip2hdr: + hwcs = h.ascardlist() + cards = self._sip2hdr('a') + hwcs.extend(cards) + cards = self._sip2hdr('b') + hwcs.extend(cards) + + try: + ap = self.sip.ap + except AssertionError: + ap = None + try: + bp = self.sip.bp + except AssertionError: + bp = None + + if ap: + cards = self._sip2hdr('ap') + hwcs.extend(cards) + if bp: + cards = self._sip2hdr('bp') + hwcs.extend(cards) + + h = pyfits.Header(hwcs) + + return h + + + def _sip2hdr(self, k): + """ + Get a set of SIP coefficients in the form of an array + and turn them into a pyfits.Cardlist. + k - one of 'a', 'b', 'ap', 'bp' + """ + + cards = pyfits.CardList() + korder = self.sip.__getattribute__(k+'_order') + cards.append(pyfits.Card(key=k.upper()+'_ORDER', value=korder)) + coeffs = self.sip.__getattribute__(k) + ind = coeffs.nonzero() + for i in range(len(ind[0])): + card = pyfits.Card(key=k.upper()+'_'+str(ind[0][i])+'_'+str(ind[1][i]), + value=coeffs[ind[0][i], ind[1][i]]) + cards.append(card) + return cards + + + def _updatehdr(self, ext_hdr): + #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 printwcs(self): + print 'WCS Keywords\n' + print 'CD_11 CD_12: %r %r' % (self.wcs.cd[0,0], self.wcs.cd[0,1]) + print 'CD_21 CD_22: %r %r' % (self.wcs.cd[1,0], self.wcs.cd[1,1]) + print 'CRVAL : %r %r' % (self.wcs.crval[0], self.wcs.crval[1]) + print 'CRPIX : %r %r' % (self.wcs.crpix[0], self.wcs.crpix[1]) + print 'NAXIS : %d %d' % (self.naxis1, self.naxis2) + print 'Plate Scale : %r' % self.pscale + print 'ORIENTAT : %r' % self.orientat + + |