lsst.fgcmcal gd8e65d7270+c37b654641
fgcmLoadReferenceCatalog.py
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23"""Load reference catalog objects for input to FGCM.
24
25This task will load multi-band reference objects and apply color terms (if
26configured). This wrapper around LoadReferenceObjects task also allows loading
27by healpix pixel (the native pixelization of fgcm), and is self-contained so
28the task can be called by third-party code.
29"""
30
31import numpy as np
32import hpgeom as hpg
33from astropy import units
34
35import lsst.pex.config as pexConfig
36import lsst.pipe.base as pipeBase
37from lsst.meas.algorithms import LoadIndexedReferenceObjectsTask, ReferenceSourceSelectorTask
38from lsst.meas.algorithms import getRefFluxField
39from lsst.pipe.tasks.colorterms import ColortermLibrary
40from lsst.afw.image import abMagErrFromFluxErr
41
42import lsst.geom
43
44__all__ = ['FgcmLoadReferenceCatalogConfig', 'FgcmLoadReferenceCatalogTask']
45
46
47class FgcmLoadReferenceCatalogConfig(pexConfig.Config):
48 """Config for FgcmLoadReferenceCatalogTask"""
49
50 refObjLoader = pexConfig.ConfigurableField(
51 target=LoadIndexedReferenceObjectsTask,
52 doc="Reference object loader for photometry",
53 deprecated="refObjLoader is deprecated, and will be removed after v24.",
54 )
55 filterMap = pexConfig.DictField(
56 doc="Mapping from physicalFilter label 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.filterMap:
79 msg = 'Must set filterMap'
80 raise pexConfig.FieldValidationError(FgcmLoadReferenceCatalogConfig.filterMap, self, msg)
81 if self.applyColorTerms and len(self.colorterms.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
86class FgcmLoadReferenceCatalogTask(pipeBase.Task):
87 """
88 Load multi-band reference objects from a reference catalog.
89
90 Parameters
91 ----------
92 refObjLoader : `lsst.meas.algorithms.ReferenceObjectLoader`
93 Reference object loader.
94 refCatName : `str`
95 Name of reference catalog (for color term lookups).
96 """
97 ConfigClass = FgcmLoadReferenceCatalogConfig
98 _DefaultName = 'fgcmLoadReferenceCatalog'
99
100 def __init__(self, refObjLoader=None, refCatName=None, **kwargs):
101 """Construct an FgcmLoadReferenceCatalogTask
102 """
103 pipeBase.Task.__init__(self, **kwargs)
104 self.refObjLoader = refObjLoader
105 self.refCatName = refCatName
106
107 if refObjLoader is None or refCatName is None:
108 raise RuntimeError("FgcmLoadReferenceCatalogTask requires a refObjLoader and refCatName.")
109
110 self.makeSubtask('referenceSelector')
111 self._fluxFilters = None
112 self._fluxFields = None
113 self._referenceFilter = None
114
115 def getFgcmReferenceStarsHealpix(self, nside, pixel, filterList, nest=False):
116 """
117 Get a reference catalog that overlaps a healpix pixel, using multiple
118 filters. In addition, apply colorterms if available.
119
120 Return format is a numpy recarray for use with fgcm, with the format:
121
122 dtype = ([('ra', `np.float64`),
123 ('dec', `np.float64`),
124 ('refMag', `np.float32`, len(filterList)),
125 ('refMagErr', `np.float32`, len(filterList)])
126
127 Reference magnitudes (AB) will be 99 for non-detections.
128
129 Parameters
130 ----------
131 nside: `int`
132 Healpix nside of pixel to load
133 pixel: `int`
134 Healpix pixel of pixel to load
135 filterList: `list`
136 list of `str` of camera filter names.
137 nest: `bool`, optional
138 Is the pixel in nest format? Default is False.
139
140 Returns
141 -------
142 fgcmRefCat: `np.recarray`
143 """
144
145 # Determine the size of the sky circle to load
146 lon, lat = hpg.pixel_to_angle(nside, pixel, nest=nest, degrees=False)
147 center = lsst.geom.SpherePoint(lon * lsst.geom.degrees, lat * lsst.geom.radians)
148
149 theta_phi = hpg.boundaries(nside, pixel, step=1, nest=nest, lonlat=False)
150
151 radius = 0.0 * lsst.geom.radians
152 for ctheta, cphi in zip(*theta_phi):
153 rad = center.separation(lsst.geom.SpherePoint(cphi * lsst.geom.radians,
154 (np.pi/2. - ctheta) * lsst.geom.radians))
155 if (rad > radius):
156 radius = rad
157
158 # Load the fgcm-format reference catalog
159 fgcmRefCat = self.getFgcmReferenceStarsSkyCircle(center.getRa().asDegrees(),
160 center.getDec().asDegrees(),
161 radius.asDegrees(),
162 filterList)
163 catPix = hpg.angle_to_pixel(nside, fgcmRefCat['ra'], fgcmRefCat['dec'], nest=nest)
164
165 inPix, = np.where(catPix == pixel)
166
167 return fgcmRefCat[inPix]
168
169 def getFgcmReferenceStarsSkyCircle(self, ra, dec, radius, filterList):
170 """
171 Get a reference catalog that overlaps a circular sky region, using
172 multiple filters. In addition, apply colorterms if available.
173
174 Return format is a numpy recarray for use with fgcm.
175
176 dtype = ([('ra', `np.float64`),
177 ('dec', `np.float64`),
178 ('refMag', `np.float32`, len(filterList)),
179 ('refMagErr', `np.float32`, len(filterList)])
180
181 Reference magnitudes (AB) will be 99 for non-detections.
182
183 Parameters
184 ----------
185 ra: `float`
186 ICRS right ascension, degrees.
187 dec: `float`
188 ICRS declination, degrees.
189 radius: `float`
190 Radius to search, degrees.
191 filterList: `list`
192 list of `str` of camera filter names.
193
194 Returns
195 -------
196 fgcmRefCat: `np.recarray`
197 """
198
199 center = lsst.geom.SpherePoint(ra * lsst.geom.degrees, dec * lsst.geom.degrees)
200
201 # Check if we haev previously cached values for the fluxFields
202 if self._fluxFilters is None or self._fluxFilters != filterList:
203 self._determine_flux_fields(center, filterList)
204
205 skyCircle = self.refObjLoader.loadSkyCircle(center,
206 radius * lsst.geom.degrees,
207 self._referenceFilter)
208
209 if not skyCircle.refCat.isContiguous():
210 refCat = skyCircle.refCat.copy(deep=True)
211 else:
212 refCat = skyCircle.refCat
213
214 # Select on raw (uncorrected) catalog, where the errors should make more sense
215 goodSources = self.referenceSelector.selectSources(refCat)
216 selected = goodSources.selected
217
218 fgcmRefCat = np.zeros(np.sum(selected), dtype=[('ra', 'f8'),
219 ('dec', 'f8'),
220 ('refMag', 'f4', len(filterList)),
221 ('refMagErr', 'f4', len(filterList))])
222 if fgcmRefCat.size == 0:
223 # Return an empty catalog if we don't have any selected sources
224 return fgcmRefCat
225
226 # The ra/dec native Angle format is radians
227 # We determine the conversion from the native units (typically
228 # radians) to degrees for the first observation. This allows us
229 # to treate ra/dec as numpy arrays rather than Angles, which would
230 # be approximately 600x slower.
231
232 conv = refCat[0]['coord_ra'].asDegrees() / float(refCat[0]['coord_ra'])
233 fgcmRefCat['ra'] = refCat['coord_ra'][selected] * conv
234 fgcmRefCat['dec'] = refCat['coord_dec'][selected] * conv
235
236 # Default (unset) values are 99.0
237 fgcmRefCat['refMag'][:, :] = 99.0
238 fgcmRefCat['refMagErr'][:, :] = 99.0
239
240 if self.config.applyColorTerms:
241 for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)):
242 if fluxField is None:
243 continue
244
245 self.log.debug("Applying color terms for filtername=%r" % (filterName))
246
247 colorterm = self.config.colorterms.getColorterm(filterName, self.refCatName, doRaise=True)
248
249 refMag, refMagErr = colorterm.getCorrectedMagnitudes(refCat)
250
251 # nan_to_num replaces nans with zeros, and this ensures that we select
252 # magnitudes that both filter out nans and are not very large (corresponding
253 # to very small fluxes), as "99" is a common sentinel for illegal magnitudes.
254
255 good, = np.where((np.nan_to_num(refMag[selected]) < 90.0)
256 & (np.nan_to_num(refMagErr[selected]) < 90.0)
257 & (np.nan_to_num(refMagErr[selected]) > 0.0))
258
259 fgcmRefCat['refMag'][good, i] = refMag[selected][good]
260 fgcmRefCat['refMagErr'][good, i] = refMagErr[selected][good]
261
262 else:
263 # No colorterms
264
265 for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)):
266 # nan_to_num replaces nans with zeros, and this ensures that we select
267 # fluxes that both filter out nans and are positive.
268 good, = np.where((np.nan_to_num(refCat[fluxField][selected]) > 0.0)
269 & (np.nan_to_num(refCat[fluxField+'Err'][selected]) > 0.0))
270 refMag = (refCat[fluxField][selected][good] * units.nJy).to_value(units.ABmag)
271 refMagErr = abMagErrFromFluxErr(refCat[fluxField+'Err'][selected][good],
272 refCat[fluxField][selected][good])
273 fgcmRefCat['refMag'][good, i] = refMag
274 fgcmRefCat['refMagErr'][good, i] = refMagErr
275
276 return fgcmRefCat
277
278 def _determine_flux_fields(self, center, filterList):
279 """
280 Determine the flux field names for a reference catalog.
281
282 Will set self._fluxFields, self._referenceFilter.
283
284 Parameters
285 ----------
286 center: `lsst.geom.SpherePoint`
287 The center around which to load test sources.
288 filterList: `list`
289 list of `str` of camera filter names.
290 """
291
292 # Record self._fluxFilters for checks on subsequent calls
293 self._fluxFilters = filterList
294
295 # Search for a good filter to use to load the reference catalog
296 # via the refObjLoader task which requires a valid filterName
297 foundReferenceFilter = False
298 for filterName in filterList:
299 refFilterName = self.config.filterMap.get(filterName)
300 if refFilterName is None:
301 continue
302
303 try:
304 results = self.refObjLoader.loadSkyCircle(center,
305 0.05 * lsst.geom.degrees,
306 refFilterName)
307 foundReferenceFilter = True
308 self._referenceFilter = refFilterName
309 break
310 except RuntimeError:
311 # This just means that the filterName wasn't listed
312 # in the reference catalog. This is okay.
313 pass
314
315 if not foundReferenceFilter:
316 raise RuntimeError("Could not find any valid flux field(s) %s" %
317 (", ".join(filterList)))
318
319 # Retrieve all the fluxField names
320 self._fluxFields = []
321 for filterName in filterList:
322 fluxField = None
323
324 refFilterName = self.config.filterMap.get(filterName)
325
326 if refFilterName is not None:
327 try:
328 fluxField = getRefFluxField(results.refCat.schema, filterName=refFilterName)
329 except RuntimeError:
330 # This flux field isn't available. Set to None
331 fluxField = None
332
333 if fluxField is None:
334 self.log.warning(f'No reference flux field for camera filter {filterName}')
335
336 self._fluxFields.append(fluxField)
def __init__(self, refObjLoader=None, refCatName=None, **kwargs)
def getFgcmReferenceStarsHealpix(self, nside, pixel, filterList, nest=False)