lsst.fgcmcal  21.0.0-3-g1ff6949+fb2fcf7d32
fgcmLoadReferenceCatalog.py
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23 """Load reference catalog objects for input to FGCM.
24 
25 This task will load multi-band reference objects and apply color terms (if
26 configured). This wrapper around LoadReferenceObjects task also allows loading
27 by healpix pixel (the native pixelization of fgcm), and is self-contained so
28 the task can be called by third-party code.
29 """
30 
31 import numpy as np
32 import healpy as hp
33 from astropy import units
34 
35 import lsst.pex.config as pexConfig
36 import lsst.pipe.base as pipeBase
37 from lsst.meas.algorithms import LoadIndexedReferenceObjectsTask, ReferenceSourceSelectorTask
38 from lsst.meas.algorithms import getRefFluxField
39 from lsst.pipe.tasks.colorterms import ColortermLibrary
40 from lsst.afw.image import abMagErrFromFluxErr
41 import lsst.geom
42 
43 __all__ = ['FgcmLoadReferenceCatalogConfig', 'FgcmLoadReferenceCatalogTask']
44 
45 
46 class FgcmLoadReferenceCatalogConfig(pexConfig.Config):
47  """Config for FgcmLoadReferenceCatalogTask"""
48 
49  refObjLoader = pexConfig.ConfigurableField(
50  target=LoadIndexedReferenceObjectsTask,
51  doc="Reference object loader for photometry",
52  )
53  refFilterMap = pexConfig.DictField(
54  doc="Mapping from camera 'filterName' to reference filter name.",
55  keytype=str,
56  itemtype=str,
57  default={},
58  )
59  applyColorTerms = pexConfig.Field(
60  doc=("Apply photometric color terms to reference stars?"
61  "Requires that colorterms be set to a ColorTermLibrary"),
62  dtype=bool,
63  default=True
64  )
65  colorterms = pexConfig.ConfigField(
66  doc="Library of photometric reference catalog name to color term dict.",
67  dtype=ColortermLibrary,
68  )
69  referenceSelector = pexConfig.ConfigurableField(
70  target=ReferenceSourceSelectorTask,
71  doc="Selection of reference sources",
72  )
73 
74  def validate(self):
75  super().validate()
76  if not self.refFilterMap:
77  msg = 'Must set refFilterMap'
78  raise pexConfig.FieldValidationError(FgcmLoadReferenceCatalogConfig.refFilterMap, self, msg)
79  if self.applyColorTerms and len(self.colorterms.data) == 0:
80  msg = "applyColorTerms=True requires the `colorterms` field be set to a ColortermLibrary."
81  raise pexConfig.FieldValidationError(FgcmLoadReferenceCatalogConfig.colorterms, self, msg)
82 
83 
84 class FgcmLoadReferenceCatalogTask(pipeBase.Task):
85  """
86  Load multi-band reference objects from a reference catalog.
87 
88  Parameters
89  ----------
90  butler: `lsst.daf.persistence.Butler`
91  Data butler for reading catalogs
92  """
93  ConfigClass = FgcmLoadReferenceCatalogConfig
94  _DefaultName = 'fgcmLoadReferenceCatalog'
95 
96  def __init__(self, butler, *args, **kwargs):
97  """Construct an FgcmLoadReferenceCatalogTask
98 
99  Parameters
100  ----------
101  butler: `lsst.daf.persistence.Buter`
102  Data butler for reading catalogs.
103  """
104  pipeBase.Task.__init__(self, *args, **kwargs)
105  self.butler = butler
106  self.makeSubtask('refObjLoader', butler=butler)
107  self.makeSubtask('referenceSelector')
108  self._fluxFilters = None
109  self._fluxFields = None
110  self._referenceFilter = None
111 
112  def getFgcmReferenceStarsHealpix(self, nside, pixel, filterList, nest=False):
113  """
114  Get a reference catalog that overlaps a healpix pixel, using multiple
115  filters. In addition, apply colorterms if available.
116 
117  Return format is a numpy recarray for use with fgcm, with the format:
118 
119  dtype = ([('ra', `np.float64`),
120  ('dec', `np.float64`),
121  ('refMag', `np.float32`, len(filterList)),
122  ('refMagErr', `np.float32`, len(filterList)])
123 
124  Reference magnitudes (AB) will be 99 for non-detections.
125 
126  Parameters
127  ----------
128  nside: `int`
129  Healpix nside of pixel to load
130  pixel: `int`
131  Healpix pixel of pixel to load
132  filterList: `list`
133  list of `str` of camera filter names.
134  nest: `bool`, optional
135  Is the pixel in nest format? Default is False.
136 
137  Returns
138  -------
139  fgcmRefCat: `np.recarray`
140  """
141 
142  # Determine the size of the sky circle to load
143  theta, phi = hp.pix2ang(nside, pixel, nest=nest)
144  center = lsst.geom.SpherePoint(phi * lsst.geom.radians, (np.pi/2. - theta) * lsst.geom.radians)
145 
146  corners = hp.boundaries(nside, pixel, step=1, nest=nest)
147  theta_phi = hp.vec2ang(np.transpose(corners))
148 
149  radius = 0.0 * lsst.geom.radians
150  for ctheta, cphi in zip(*theta_phi):
151  rad = center.separation(lsst.geom.SpherePoint(cphi * lsst.geom.radians,
152  (np.pi/2. - ctheta) * lsst.geom.radians))
153  if (rad > radius):
154  radius = rad
155 
156  # Load the fgcm-format reference catalog
157  fgcmRefCat = self.getFgcmReferenceStarsSkyCircle(center.getRa().asDegrees(),
158  center.getDec().asDegrees(),
159  radius.asDegrees(),
160  filterList)
161  catPix = hp.ang2pix(nside, np.radians(90.0 - fgcmRefCat['dec']),
162  np.radians(fgcmRefCat['ra']), nest=nest)
163 
164  inPix, = np.where(catPix == pixel)
165 
166  return fgcmRefCat[inPix]
167 
168  def getFgcmReferenceStarsSkyCircle(self, ra, dec, radius, filterList):
169  """
170  Get a reference catalog that overlaps a circular sky region, using
171  multiple filters. In addition, apply colorterms if available.
172 
173  Return format is a numpy recarray for use with fgcm.
174 
175  dtype = ([('ra', `np.float64`),
176  ('dec', `np.float64`),
177  ('refMag', `np.float32`, len(filterList)),
178  ('refMagErr', `np.float32`, len(filterList)])
179 
180  Reference magnitudes (AB) will be 99 for non-detections.
181 
182  Parameters
183  ----------
184  ra: `float`
185  ICRS right ascension, degrees.
186  dec: `float`
187  ICRS declination, degrees.
188  radius: `float`
189  Radius to search, degrees.
190  filterList: `list`
191  list of `str` of camera filter names.
192 
193  Returns
194  -------
195  fgcmRefCat: `np.recarray`
196  """
197 
198  center = lsst.geom.SpherePoint(ra * lsst.geom.degrees, dec * lsst.geom.degrees)
199 
200  # Check if we haev previously cached values for the fluxFields
201  if self._fluxFilters is None or self._fluxFilters != filterList:
202  self._determine_flux_fields(center, filterList)
203 
204  skyCircle = self.refObjLoader.loadSkyCircle(center,
205  radius * lsst.geom.degrees,
206  self._referenceFilter)
207 
208  if not skyCircle.refCat.isContiguous():
209  refCat = skyCircle.refCat.copy(deep=True)
210  else:
211  refCat = skyCircle.refCat
212 
213  # Select on raw (uncorrected) catalog, where the errors should make more sense
214  goodSources = self.referenceSelector.selectSources(refCat)
215  selected = goodSources.selected
216 
217  fgcmRefCat = np.zeros(np.sum(selected), dtype=[('ra', 'f8'),
218  ('dec', 'f8'),
219  ('refMag', 'f4', len(filterList)),
220  ('refMagErr', 'f4', len(filterList))])
221  if fgcmRefCat.size == 0:
222  # Return an empty catalog if we don't have any selected sources
223  return fgcmRefCat
224 
225  # The ra/dec native Angle format is radians
226  # We determine the conversion from the native units (typically
227  # radians) to degrees for the first observation. This allows us
228  # to treate ra/dec as numpy arrays rather than Angles, which would
229  # be approximately 600x slower.
230 
231  conv = refCat[0]['coord_ra'].asDegrees() / float(refCat[0]['coord_ra'])
232  fgcmRefCat['ra'] = refCat['coord_ra'][selected] * conv
233  fgcmRefCat['dec'] = refCat['coord_dec'][selected] * conv
234 
235  # Default (unset) values are 99.0
236  fgcmRefCat['refMag'][:, :] = 99.0
237  fgcmRefCat['refMagErr'][:, :] = 99.0
238 
239  if self.config.applyColorTerms:
240  try:
241  refCatName = self.refObjLoader.ref_dataset_name
242  except AttributeError:
243  # NOTE: we need this try:except: block in place until we've
244  # completely removed a.net support
245  raise RuntimeError("Cannot perform colorterm corrections with a.net refcats.")
246 
247  for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)):
248  if fluxField is None:
249  continue
250 
251  self.log.debug("Applying color terms for filtername=%r" % (filterName))
252 
253  colorterm = self.config.colorterms.getColorterm(
254  filterName=filterName, photoCatName=refCatName, doRaise=True)
255 
256  refMag, refMagErr = colorterm.getCorrectedMagnitudes(refCat, filterName)
257 
258  # nan_to_num replaces nans with zeros, and this ensures that we select
259  # magnitudes that both filter out nans and are not very large (corresponding
260  # to very small fluxes), as "99" is a common sentinel for illegal magnitudes.
261 
262  good, = np.where((np.nan_to_num(refMag[selected]) < 90.0) &
263  (np.nan_to_num(refMagErr[selected]) < 90.0) &
264  (np.nan_to_num(refMagErr[selected]) > 0.0))
265 
266  fgcmRefCat['refMag'][good, i] = refMag[selected][good]
267  fgcmRefCat['refMagErr'][good, i] = refMagErr[selected][good]
268 
269  else:
270  # No colorterms
271 
272  # TODO: need to use Jy here until RFC-549 is completed and refcats return nanojansky
273 
274  for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)):
275  # nan_to_num replaces nans with zeros, and this ensures that we select
276  # fluxes that both filter out nans and are positive.
277  good, = np.where((np.nan_to_num(refCat[fluxField][selected]) > 0.0) &
278  (np.nan_to_num(refCat[fluxField+'Err'][selected]) > 0.0))
279  refMag = (refCat[fluxField][selected][good] * units.Jy).to_value(units.ABmag)
280  refMagErr = abMagErrFromFluxErr(refCat[fluxField+'Err'][selected][good],
281  refCat[fluxField][selected][good])
282  fgcmRefCat['refMag'][good, i] = refMag
283  fgcmRefCat['refMagErr'][good, i] = refMagErr
284 
285  return fgcmRefCat
286 
287  def _determine_flux_fields(self, center, filterList):
288  """
289  Determine the flux field names for a reference catalog.
290 
291  Will set self._fluxFields, self._referenceFilter.
292 
293  Parameters
294  ----------
295  center: `lsst.geom.SpherePoint`
296  The center around which to load test sources.
297  filterList: `list`
298  list of `str` of camera filter names.
299  """
300 
301  # Record self._fluxFilters for checks on subsequent calls
302  self._fluxFilters = filterList
303 
304  # Search for a good filter to use to load the reference catalog
305  # via the refObjLoader task which requires a valid filterName
306  foundReferenceFilter = False
307  for filterName in filterList:
308  refFilterName = self.config.refFilterMap.get(filterName)
309  if refFilterName is None:
310  continue
311 
312  try:
313  results = self.refObjLoader.loadSkyCircle(center,
314  0.05 * lsst.geom.degrees,
315  refFilterName)
316  foundReferenceFilter = True
317  self._referenceFilter = refFilterName
318  break
319  except RuntimeError:
320  # This just means that the filterName wasn't listed
321  # in the reference catalog. This is okay.
322  pass
323 
324  if not foundReferenceFilter:
325  raise RuntimeError("Could not find any valid flux field(s) %s" %
326  (", ".join(filterList)))
327 
328  # Retrieve all the fluxField names
329  self._fluxFields = []
330  for filterName in filterList:
331  fluxField = None
332 
333  refFilterName = self.config.refFilterMap.get(filterName)
334 
335  if refFilterName is not None:
336  try:
337  fluxField = getRefFluxField(results.refCat.schema, filterName=refFilterName)
338  except RuntimeError:
339  # This flux field isn't available. Set to None
340  fluxField = None
341 
342  if fluxField is None:
343  self.log.warn(f'No reference flux field for camera filter {filterName}')
344 
345  self._fluxFields.append(fluxField)
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogConfig
Definition: fgcmLoadReferenceCatalog.py:46
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask.getFgcmReferenceStarsSkyCircle
def getFgcmReferenceStarsSkyCircle(self, ra, dec, radius, filterList)
Definition: fgcmLoadReferenceCatalog.py:168
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask._referenceFilter
_referenceFilter
Definition: fgcmLoadReferenceCatalog.py:110
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogConfig.colorterms
colorterms
Definition: fgcmLoadReferenceCatalog.py:65
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogConfig.applyColorTerms
applyColorTerms
Definition: fgcmLoadReferenceCatalog.py:59
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogConfig.refFilterMap
refFilterMap
Definition: fgcmLoadReferenceCatalog.py:53
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask._determine_flux_fields
def _determine_flux_fields(self, center, filterList)
Definition: fgcmLoadReferenceCatalog.py:287
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask.__init__
def __init__(self, butler, *args, **kwargs)
Definition: fgcmLoadReferenceCatalog.py:96
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogConfig.validate
def validate(self)
Definition: fgcmLoadReferenceCatalog.py:74
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask.butler
butler
Definition: fgcmLoadReferenceCatalog.py:105
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask._fluxFields
_fluxFields
Definition: fgcmLoadReferenceCatalog.py:109
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask
Definition: fgcmLoadReferenceCatalog.py:84
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask._fluxFilters
_fluxFilters
Definition: fgcmLoadReferenceCatalog.py:108
lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask.getFgcmReferenceStarsHealpix
def getFgcmReferenceStarsHealpix(self, nside, pixel, filterList, nest=False)
Definition: fgcmLoadReferenceCatalog.py:112