Coverage for python/lsst/fgcmcal/fgcmLoadReferenceCatalog.py : 17%

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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.
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"""
31import numpy as np
32import healpy as hp
33from astropy import units
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
41import lsst.geom
43__all__ = ['FgcmLoadReferenceCatalogConfig', 'FgcmLoadReferenceCatalogTask']
46class FgcmLoadReferenceCatalogConfig(pexConfig.Config):
47 """Config for FgcmLoadReferenceCatalogTask"""
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 )
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)
84class FgcmLoadReferenceCatalogTask(pipeBase.Task):
85 """
86 Load multi-band reference objects from a reference catalog.
88 Paramters
89 ---------
90 butler: `lsst.daf.persistence.Butler`
91 Data butler for reading catalogs
92 """
93 ConfigClass = FgcmLoadReferenceCatalogConfig
94 _DefaultName = 'fgcmLoadReferenceCatalog'
96 def __init__(self, butler, *args, **kwargs):
97 """Construct an FgcmLoadReferenceCatalogTask
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
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.
117 Return format is a numpy recarray for use with fgcm.
119 Parameters
120 ----------
121 nside: `int`
122 Healpix nside of pixel to load
123 pixel: `int`
124 Healpix pixel of pixel to load
125 filterList: `list`
126 list of `str` of camera filter names.
127 nest: `bool`, optional
128 Is the pixel in nest format? Default is False.
130 Returns
131 -------
132 fgcmRefCat: `np.recarray`
133 Numpy recarray with the following fields:
134 ra: `np.float64`
135 Right ascension, degrees
136 dec: `np.float64`
137 Declination, degrees
138 refMag: (`np.float32`, len(filterList))
139 Reference magnitude for filterList bands
140 Will be 99 for non-detections.
141 refMagErr: (`np.float32`, len(filterList))
142 Reference magnitude error for filterList bands
143 Will be 99 for non-detections.
144 """
146 # Determine the size of the sky circle to load
147 theta, phi = hp.pix2ang(nside, pixel, nest=nest)
148 center = lsst.geom.SpherePoint(phi * lsst.geom.radians, (np.pi/2. - theta) * lsst.geom.radians)
150 corners = hp.boundaries(nside, pixel, step=1, nest=nest)
151 theta_phi = hp.vec2ang(np.transpose(corners))
153 radius = 0.0 * lsst.geom.radians
154 for ctheta, cphi in zip(*theta_phi):
155 rad = center.separation(lsst.geom.SpherePoint(cphi * lsst.geom.radians,
156 (np.pi/2. - ctheta) * lsst.geom.radians))
157 if (rad > radius):
158 radius = rad
160 # Load the fgcm-format reference catalog
161 fgcmRefCat = self.getFgcmReferenceStarsSkyCircle(center.getRa().asDegrees(),
162 center.getDec().asDegrees(),
163 radius.asDegrees(),
164 filterList)
165 catPix = hp.ang2pix(nside, np.radians(90.0 - fgcmRefCat['dec']),
166 np.radians(fgcmRefCat['ra']), nest=nest)
168 inPix, = np.where(catPix == pixel)
170 return fgcmRefCat[inPix]
172 def getFgcmReferenceStarsSkyCircle(self, ra, dec, radius, filterList):
173 """
174 Get a reference catalog that overlaps a circular sky region, using
175 multiple filters. In addition, apply colorterms if available.
177 Return format is a numpy recarray for use with fgcm.
179 Parameters
180 ----------
181 ra: `float`
182 ICRS right ascension, degrees.
183 dec: `float`
184 ICRS declination, degrees.
185 radius: `float`
186 Radius to search, degrees.
187 filterList: `list`
188 list of `str` of camera filter names.
190 Returns
191 -------
192 fgcmRefCat: `np.recarray`
193 Numpy recarray with the following fields:
194 ra: `np.float64`
195 Right ascension, degrees
196 dec: `np.float64`
197 Declination, degrees
198 refMag: (`np.float32`, len(filterList))
199 Reference magnitude for filterList bands
200 Will be 99 for non-detections.
201 refMagErr: (`np.float32`, len(filterList))
202 Reference magnitude error for filterList bands
203 Will be 99 for non-detections.
204 """
206 center = lsst.geom.SpherePoint(ra * lsst.geom.degrees, dec * lsst.geom.degrees)
208 # Check if we haev previously cached values for the fluxFields
209 if self._fluxFilters is None or self._fluxFilters != filterList:
210 self._determine_flux_fields(center, filterList)
212 skyCircle = self.refObjLoader.loadSkyCircle(center,
213 radius * lsst.geom.degrees,
214 self._referenceFilter)
216 if not skyCircle.refCat.isContiguous():
217 refCat = skyCircle.refCat.copy(deep=True)
218 else:
219 refCat = skyCircle.refCat
221 # Select on raw (uncorrected) catalog, where the errors should make more sense
222 goodSources = self.referenceSelector.selectSources(refCat)
223 selected = goodSources.selected
225 fgcmRefCat = np.zeros(np.sum(selected), dtype=[('ra', 'f8'),
226 ('dec', 'f8'),
227 ('refMag', 'f4', len(filterList)),
228 ('refMagErr', 'f4', len(filterList))])
229 if fgcmRefCat.size == 0:
230 # Return an empty catalog if we don't have any selected sources
231 return fgcmRefCat
233 # The ra/dec native Angle format is radians
234 # We determine the conversion from the native units (typically
235 # radians) to degrees for the first observation. This allows us
236 # to treate ra/dec as numpy arrays rather than Angles, which would
237 # be approximately 600x slower.
239 conv = refCat[0]['coord_ra'].asDegrees() / float(refCat[0]['coord_ra'])
240 fgcmRefCat['ra'] = refCat['coord_ra'][selected] * conv
241 fgcmRefCat['dec'] = refCat['coord_dec'][selected] * conv
243 # Default (unset) values are 99.0
244 fgcmRefCat['refMag'][:, :] = 99.0
245 fgcmRefCat['refMagErr'][:, :] = 99.0
247 if self.config.applyColorTerms:
248 try:
249 refCatName = self.refObjLoader.ref_dataset_name
250 except AttributeError:
251 # NOTE: we need this try:except: block in place until we've
252 # completely removed a.net support
253 raise RuntimeError("Cannot perform colorterm corrections with a.net refcats.")
255 for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)):
256 if fluxField is None:
257 continue
259 self.log.debug("Applying color terms for filtername=%r" % (filterName))
261 colorterm = self.config.colorterms.getColorterm(
262 filterName=filterName, photoCatName=refCatName, doRaise=True)
264 refMag, refMagErr = colorterm.getCorrectedMagnitudes(refCat, filterName)
266 # nan_to_num replaces nans with zeros, and this ensures that we select
267 # magnitudes that both filter out nans and are not very large (corresponding
268 # to very small fluxes), as "99" is a common sentinel for illegal magnitudes.
270 good, = np.where((np.nan_to_num(refMag[selected]) < 90.0) &
271 (np.nan_to_num(refMagErr[selected]) < 90.0) &
272 (np.nan_to_num(refMagErr[selected]) > 0.0))
274 fgcmRefCat['refMag'][good, i] = refMag[selected][good]
275 fgcmRefCat['refMagErr'][good, i] = refMagErr[selected][good]
277 else:
278 # No colorterms
280 # TODO: need to use Jy here until RFC-549 is completed and refcats return nanojansky
282 for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)):
283 # nan_to_num replaces nans with zeros, and this ensures that we select
284 # fluxes that both filter out nans and are positive.
285 good, = np.where((np.nan_to_num(refCat[fluxField][selected]) > 0.0) &
286 (np.nan_to_num(refCat[fluxField+'Err'][selected]) > 0.0))
287 refMag = (refCat[fluxField][selected][good] * units.Jy).to_value(units.ABmag)
288 refMagErr = abMagErrFromFluxErr(refCat[fluxField+'Err'][selected][good],
289 refCat[fluxField][selected][good])
290 fgcmRefCat['refMag'][good, i] = refMag
291 fgcmRefCat['refMagErr'][good, i] = refMagErr
293 return fgcmRefCat
295 def _determine_flux_fields(self, center, filterList):
296 """
297 Determine the flux field names for a reference catalog.
299 Will set self._fluxFields, self._referenceFilter.
301 Parameters
302 ----------
303 center: `lsst.geom.SpherePoint`
304 The center around which to load test sources.
305 filterList: `list`
306 list of `str` of camera filter names.
307 """
309 # Record self._fluxFilters for checks on subsequent calls
310 self._fluxFilters = filterList
312 # Search for a good filter to use to load the reference catalog
313 # via the refObjLoader task which requires a valid filterName
314 foundReferenceFilter = False
315 for filterName in filterList:
316 refFilterName = self.config.refFilterMap.get(filterName)
317 if refFilterName is None:
318 continue
320 try:
321 results = self.refObjLoader.loadSkyCircle(center,
322 0.05 * lsst.geom.degrees,
323 refFilterName)
324 foundReferenceFilter = True
325 self._referenceFilter = refFilterName
326 break
327 except RuntimeError:
328 # This just means that the filterName wasn't listed
329 # in the reference catalog. This is okay.
330 pass
332 if not foundReferenceFilter:
333 raise RuntimeError("Could not find any valid flux field(s) %s" %
334 (", ".join(filterList)))
336 # Retrieve all the fluxField names
337 self._fluxFields = []
338 for filterName in filterList:
339 fluxField = None
341 refFilterName = self.config.refFilterMap.get(filterName)
343 if refFilterName is not None:
344 try:
345 fluxField = getRefFluxField(results.refCat.schema, filterName=refFilterName)
346 except RuntimeError:
347 # This flux field isn't available. Set to None
348 fluxField = None
350 if fluxField is None:
351 self.log.warn(f'No reference flux field for camera filter {filterName}')
353 self._fluxFields.append(fluxField)