lsst.fgcmcal  21.0.0-5-gb155db7+5dc39e03a1
fgcmLoadReferenceCatalog.py
Go to the documentation of this file.
1 # See COPYRIGHT file at the top of the source tree.
2 #
3 # This file is part of fgcmcal.
4 #
5 # Developed for the LSST Data Management System.
6 # This product includes software developed by the LSST Project
7 # (https://www.lsst.org).
8 # See the COPYRIGHT file at the top-level directory of this distribution
9 # for details of code ownership.
10 #
11 # This program is free software: you can redistribute it and/or modify
12 # it under the terms of the GNU General Public License as published by
13 # the Free Software Foundation, either version 3 of the License, or
14 # (at your option) any later version.
15 #
16 # This program is distributed in the hope that it will be useful,
17 # but WITHOUT ANY WARRANTY; without even the implied warranty of
18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 # GNU General Public License for more details.
20 #
21 # You should have received a copy of the GNU General Public License
22 # along with this program. If not, see <https://www.gnu.org/licenses/>.
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 from lsst.meas.algorithms import ReferenceObjectLoader
42 
43 import lsst.geom
44 
45 __all__ = ['FgcmLoadReferenceCatalogConfig', 'FgcmLoadReferenceCatalogTask']
46 
47 
48 class FgcmLoadReferenceCatalogConfig(pexConfig.Config):
49  """Config for FgcmLoadReferenceCatalogTask"""
50 
51  refObjLoader = pexConfig.ConfigurableField(
52  target=LoadIndexedReferenceObjectsTask,
53  doc="Reference object loader for photometry",
54  )
55  refFilterMap = pexConfig.DictField(
56  doc="Mapping from camera 'filterName' to reference filter name.",
57  keytype=str,
58  itemtype=str,
59  default={},
60  )
61  applyColorTerms = pexConfig.Field(
62  doc=("Apply photometric color terms to reference stars?"
63  "Requires that colorterms be set to a ColorTermLibrary"),
64  dtype=bool,
65  default=True
66  )
67  colorterms = pexConfig.ConfigField(
68  doc="Library of photometric reference catalog name to color term dict.",
69  dtype=ColortermLibrary,
70  )
71  referenceSelector = pexConfig.ConfigurableField(
72  target=ReferenceSourceSelectorTask,
73  doc="Selection of reference sources",
74  )
75 
76  def validate(self):
77  super().validate()
78  if not self.refFilterMaprefFilterMap:
79  msg = 'Must set refFilterMap'
80  raise pexConfig.FieldValidationError(FgcmLoadReferenceCatalogConfig.refFilterMap, self, msg)
81  if self.applyColorTermsapplyColorTerms and len(self.colortermscolorterms.data) == 0:
82  msg = "applyColorTerms=True requires the `colorterms` field be set to a ColortermLibrary."
83  raise pexConfig.FieldValidationError(FgcmLoadReferenceCatalogConfig.colorterms, self, msg)
84 
85 
86 class FgcmLoadReferenceCatalogTask(pipeBase.Task):
87  """
88  Load multi-band reference objects from a reference catalog.
89 
90  Parameters
91  ----------
92  butler: `lsst.daf.persistence.Butler`
93  Data butler for reading catalogs
94  """
95  ConfigClass = FgcmLoadReferenceCatalogConfig
96  _DefaultName = 'fgcmLoadReferenceCatalog'
97 
98  def __init__(self, butler=None, refObjLoader=None, **kwargs):
99  """Construct an FgcmLoadReferenceCatalogTask
100 
101  Parameters
102  ----------
103  butler: `lsst.daf.persistence.Buter`
104  Data butler for reading catalogs.
105  """
106  pipeBase.Task.__init__(self, **kwargs)
107  if refObjLoader is None and butler is not None:
108  self.makeSubtask('refObjLoader', butler=butler)
109  else:
110  self.refObjLoaderrefObjLoader = refObjLoader
111 
112  self.makeSubtask('referenceSelector')
113  self._fluxFilters_fluxFilters = None
114  self._fluxFields_fluxFields = None
115  self._referenceFilter_referenceFilter = None
116 
117  def getFgcmReferenceStarsHealpix(self, nside, pixel, filterList, nest=False):
118  """
119  Get a reference catalog that overlaps a healpix pixel, using multiple
120  filters. In addition, apply colorterms if available.
121 
122  Return format is a numpy recarray for use with fgcm, with the format:
123 
124  dtype = ([('ra', `np.float64`),
125  ('dec', `np.float64`),
126  ('refMag', `np.float32`, len(filterList)),
127  ('refMagErr', `np.float32`, len(filterList)])
128 
129  Reference magnitudes (AB) will be 99 for non-detections.
130 
131  Parameters
132  ----------
133  nside: `int`
134  Healpix nside of pixel to load
135  pixel: `int`
136  Healpix pixel of pixel to load
137  filterList: `list`
138  list of `str` of camera filter names.
139  nest: `bool`, optional
140  Is the pixel in nest format? Default is False.
141 
142  Returns
143  -------
144  fgcmRefCat: `np.recarray`
145  """
146 
147  # Determine the size of the sky circle to load
148  theta, phi = hp.pix2ang(nside, pixel, nest=nest)
149  center = lsst.geom.SpherePoint(phi * lsst.geom.radians, (np.pi/2. - theta) * lsst.geom.radians)
150 
151  corners = hp.boundaries(nside, pixel, step=1, nest=nest)
152  theta_phi = hp.vec2ang(np.transpose(corners))
153 
154  radius = 0.0 * lsst.geom.radians
155  for ctheta, cphi in zip(*theta_phi):
156  rad = center.separation(lsst.geom.SpherePoint(cphi * lsst.geom.radians,
157  (np.pi/2. - ctheta) * lsst.geom.radians))
158  if (rad > radius):
159  radius = rad
160 
161  # Load the fgcm-format reference catalog
162  fgcmRefCat = self.getFgcmReferenceStarsSkyCirclegetFgcmReferenceStarsSkyCircle(center.getRa().asDegrees(),
163  center.getDec().asDegrees(),
164  radius.asDegrees(),
165  filterList)
166  catPix = hp.ang2pix(nside, np.radians(90.0 - fgcmRefCat['dec']),
167  np.radians(fgcmRefCat['ra']), nest=nest)
168 
169  inPix, = np.where(catPix == pixel)
170 
171  return fgcmRefCat[inPix]
172 
173  def getFgcmReferenceStarsSkyCircle(self, ra, dec, radius, filterList):
174  """
175  Get a reference catalog that overlaps a circular sky region, using
176  multiple filters. In addition, apply colorterms if available.
177 
178  Return format is a numpy recarray for use with fgcm.
179 
180  dtype = ([('ra', `np.float64`),
181  ('dec', `np.float64`),
182  ('refMag', `np.float32`, len(filterList)),
183  ('refMagErr', `np.float32`, len(filterList)])
184 
185  Reference magnitudes (AB) will be 99 for non-detections.
186 
187  Parameters
188  ----------
189  ra: `float`
190  ICRS right ascension, degrees.
191  dec: `float`
192  ICRS declination, degrees.
193  radius: `float`
194  Radius to search, degrees.
195  filterList: `list`
196  list of `str` of camera filter names.
197 
198  Returns
199  -------
200  fgcmRefCat: `np.recarray`
201  """
202 
203  center = lsst.geom.SpherePoint(ra * lsst.geom.degrees, dec * lsst.geom.degrees)
204 
205  # Check if we haev previously cached values for the fluxFields
206  if self._fluxFilters_fluxFilters is None or self._fluxFilters_fluxFilters != filterList:
207  self._determine_flux_fields_determine_flux_fields(center, filterList)
208 
209  skyCircle = self.refObjLoaderrefObjLoader.loadSkyCircle(center,
210  radius * lsst.geom.degrees,
211  self._referenceFilter_referenceFilter)
212 
213  if not skyCircle.refCat.isContiguous():
214  refCat = skyCircle.refCat.copy(deep=True)
215  else:
216  refCat = skyCircle.refCat
217 
218  # Select on raw (uncorrected) catalog, where the errors should make more sense
219  goodSources = self.referenceSelector.selectSources(refCat)
220  selected = goodSources.selected
221 
222  fgcmRefCat = np.zeros(np.sum(selected), dtype=[('ra', 'f8'),
223  ('dec', 'f8'),
224  ('refMag', 'f4', len(filterList)),
225  ('refMagErr', 'f4', len(filterList))])
226  if fgcmRefCat.size == 0:
227  # Return an empty catalog if we don't have any selected sources
228  return fgcmRefCat
229 
230  # The ra/dec native Angle format is radians
231  # We determine the conversion from the native units (typically
232  # radians) to degrees for the first observation. This allows us
233  # to treate ra/dec as numpy arrays rather than Angles, which would
234  # be approximately 600x slower.
235 
236  conv = refCat[0]['coord_ra'].asDegrees() / float(refCat[0]['coord_ra'])
237  fgcmRefCat['ra'] = refCat['coord_ra'][selected] * conv
238  fgcmRefCat['dec'] = refCat['coord_dec'][selected] * conv
239 
240  # Default (unset) values are 99.0
241  fgcmRefCat['refMag'][:, :] = 99.0
242  fgcmRefCat['refMagErr'][:, :] = 99.0
243 
244  if self.config.applyColorTerms:
245  if isinstance(self.refObjLoaderrefObjLoader, ReferenceObjectLoader):
246  # Gen3
247  refCatName = self.refObjLoaderrefObjLoader.config.value.ref_dataset_name
248  else:
249  # Gen2
250  refCatName = self.refObjLoaderrefObjLoader.ref_dataset_name
251 
252  for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters_fluxFilters, self._fluxFields_fluxFields)):
253  if fluxField is None:
254  continue
255 
256  self.log.debug("Applying color terms for filtername=%r" % (filterName))
257 
258  colorterm = self.config.colorterms.getColorterm(
259  filterName=filterName, photoCatName=refCatName, doRaise=True)
260 
261  refMag, refMagErr = colorterm.getCorrectedMagnitudes(refCat, filterName)
262 
263  # nan_to_num replaces nans with zeros, and this ensures that we select
264  # magnitudes that both filter out nans and are not very large (corresponding
265  # to very small fluxes), as "99" is a common sentinel for illegal magnitudes.
266 
267  good, = np.where((np.nan_to_num(refMag[selected]) < 90.0)
268  & (np.nan_to_num(refMagErr[selected]) < 90.0)
269  & (np.nan_to_num(refMagErr[selected]) > 0.0))
270 
271  fgcmRefCat['refMag'][good, i] = refMag[selected][good]
272  fgcmRefCat['refMagErr'][good, i] = refMagErr[selected][good]
273 
274  else:
275  # No colorterms
276 
277  for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters_fluxFilters, self._fluxFields_fluxFields)):
278  # nan_to_num replaces nans with zeros, and this ensures that we select
279  # fluxes that both filter out nans and are positive.
280  good, = np.where((np.nan_to_num(refCat[fluxField][selected]) > 0.0)
281  & (np.nan_to_num(refCat[fluxField+'Err'][selected]) > 0.0))
282  refMag = (refCat[fluxField][selected][good] * units.nJy).to_value(units.ABmag)
283  refMagErr = abMagErrFromFluxErr(refCat[fluxField+'Err'][selected][good],
284  refCat[fluxField][selected][good])
285  fgcmRefCat['refMag'][good, i] = refMag
286  fgcmRefCat['refMagErr'][good, i] = refMagErr
287 
288  return fgcmRefCat
289 
290  def _determine_flux_fields(self, center, filterList):
291  """
292  Determine the flux field names for a reference catalog.
293 
294  Will set self._fluxFields, self._referenceFilter.
295 
296  Parameters
297  ----------
298  center: `lsst.geom.SpherePoint`
299  The center around which to load test sources.
300  filterList: `list`
301  list of `str` of camera filter names.
302  """
303 
304  # Record self._fluxFilters for checks on subsequent calls
305  self._fluxFilters_fluxFilters = filterList
306 
307  # Search for a good filter to use to load the reference catalog
308  # via the refObjLoader task which requires a valid filterName
309  foundReferenceFilter = False
310  for filterName in filterList:
311  refFilterName = self.config.refFilterMap.get(filterName)
312  if refFilterName is None:
313  continue
314 
315  try:
316  results = self.refObjLoaderrefObjLoader.loadSkyCircle(center,
317  0.05 * lsst.geom.degrees,
318  refFilterName)
319  foundReferenceFilter = True
320  self._referenceFilter_referenceFilter = refFilterName
321  break
322  except RuntimeError:
323  # This just means that the filterName wasn't listed
324  # in the reference catalog. This is okay.
325  pass
326 
327  if not foundReferenceFilter:
328  raise RuntimeError("Could not find any valid flux field(s) %s" %
329  (", ".join(filterList)))
330 
331  # Retrieve all the fluxField names
332  self._fluxFields_fluxFields = []
333  for filterName in filterList:
334  fluxField = None
335 
336  refFilterName = self.config.refFilterMap.get(filterName)
337 
338  if refFilterName is not None:
339  try:
340  fluxField = getRefFluxField(results.refCat.schema, filterName=refFilterName)
341  except RuntimeError:
342  # This flux field isn't available. Set to None
343  fluxField = None
344 
345  if fluxField is None:
346  self.log.warn(f'No reference flux field for camera filter {filterName}')
347 
348  self._fluxFields_fluxFields.append(fluxField)
def __init__(self, butler=None, refObjLoader=None, **kwargs)
def getFgcmReferenceStarsHealpix(self, nside, pixel, filterList, nest=False)