lsst.meas.base  13.0-33-gb1a1d47+1
forcedPhotCoadd.py
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1 #!/usr/bin/env python
2 #
3 # LSST Data Management System
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23 from builtins import zip
24 
25 import lsst.pex.config
26 import lsst.pipe.base
27 import lsst.coadd.utils
28 import lsst.afw.table
29 
30 from .forcedPhotImage import ForcedPhotImageConfig, ForcedPhotImageTask
31 
32 __all__ = ("ForcedPhotCoaddConfig", "ForcedPhotCoaddTask")
33 
34 
36  footprintDatasetName = lsst.pex.config.Field(
37  doc="Dataset (without coadd prefix) that should be used to obtain (Heavy)Footprints for sources. "
38  "Must have IDs that match those of the reference catalog."
39  "If None, Footprints will be generated by transforming the reference Footprints.",
40  dtype=str,
41  default="meas",
42  optional=True
43  )
44 
45  def setDefaults(self):
46  ForcedPhotImageTask.ConfigClass.setDefaults(self)
47  # Copy 'id' and 'parent' columns without renaming them; since these are
48  # the only IDs we have in coadd processing, there's no need to qualify
49  # them with 'object'.
50  self.measurement.copyColumns["id"] = "id"
51  self.measurement.copyColumns["parent"] = "parent"
52  self.references.removePatchOverlaps = False # see validate() for why
53 
54  def validate(self):
55  ForcedPhotImageTask.ConfigClass.validate(self)
56  if (self.measurement.doReplaceWithNoise and self.footprintDatasetName is not None
57  and self.references.removePatchOverlaps):
58  raise ValueError("Cannot use removePatchOverlaps=True with deblended footprints, as parent "
59  "sources may be rejected while their children are not.")
60 
61 
67 
68 
70  """!
71  A command-line driver for performing forced measurement on coadd images
72 
73  This task is a subclass of ForcedPhotImageTask which is specifically for doing forced
74  measurement on a coadd, using as a reference catalog detections which were made on overlapping
75  coadds (i.e. in other bands).
76 
77  The run method (inherited from ForcedPhotImageTask) takes a lsst.daf.persistence.ButlerDataRef
78  argument that corresponds to a coadd image. This is used to provide all the inputs and outputs
79  for the task:
80  - A "*Coadd_src" (e.g. "deepCoadd_src") dataset is used as the reference catalog. This not loaded
81  directly from the passed dataRef, however; only the patch and tract are used, while the filter
82  is set by the configuration for the references subtask (see CoaddSrcReferencesTask).
83  - A "*Coadd_calexp" (e.g. "deepCoadd_calexp") dataset is used as the measurement image. Note that
84  this means that ProcessCoaddTask must be run on an image before ForcedPhotCoaddTask, in order
85  to generate the "*Coadd_calexp" dataset.
86  - A "*Coadd_forced_src" (e.g. "deepCoadd_forced_src") dataset will be written with the output
87  measurement catalog.
88 
89  In addition to the run method, ForcedPhotCcdTask overrides several methods of ForcedPhotImageTask
90  to specialize it for coadd processing, including makeIdFactory() and fetchReferences(). None of these
91  should be called directly by the user, though it may be useful to override them further in subclasses.
92  """
93 
94  ConfigClass = ForcedPhotCoaddConfig
95  RunnerClass = lsst.pipe.base.ButlerInitializedTaskRunner
96  _DefaultName = "forcedPhotCoadd"
97  dataPrefix = "deepCoadd_"
98 
99  def getExposure(self, dataRef):
100  name = self.config.coaddName + "Coadd_calexp"
101  return dataRef.get(name) if dataRef.datasetExists(name) else None
102 
103  def makeIdFactory(self, dataRef):
104  """Create an object that generates globally unique source IDs from per-CCD IDs and the CCD ID.
105 
106  @param dataRef Data reference from butler. The "CoaddId_bits" and "CoaddId"
107  datasets are accessed. The data ID must have tract and patch keys.
108  """
109  # With the default configuration, this IdFactory doesn't do anything, because
110  # the IDs it generates are immediately overwritten by the ID from the reference
111  # catalog (since that's in config.measurement.copyColumns). But we create one here anyway, to
112  # allow us to revert back to the old behavior of generating new forced source IDs,
113  # just by renaming the ID in config.copyColumns to "object_id".
114  expBits = dataRef.get(self.config.coaddName + "CoaddId_bits")
115  expId = int(dataRef.get(self.config.coaddName + "CoaddId"))
116  return lsst.afw.table.IdFactory.makeSource(expId, 64 - expBits)
117 
118  def getExposureId(self, dataRef):
119  return int(dataRef.get(self.config.coaddName + "CoaddId"))
120 
121  def fetchReferences(self, dataRef, exposure):
122  """Return an iterable of reference sources which overlap the exposure
123 
124  @param dataRef Data reference from butler corresponding to the image to be measured;
125  should have tract, patch, and filter keys.
126  @param exposure lsst.afw.image.Exposure to be measured (not used by this implementation)
127 
128  All work is delegated to the references subtask; see CoaddSrcReferencesTask for information
129  about the default behavior.
130  """
131  skyMap = dataRef.get(self.dataPrefix + "skyMap", immediate=True)
132  tractInfo = skyMap[dataRef.dataId["tract"]]
133  patch = tuple(int(v) for v in dataRef.dataId["patch"].split(","))
134  patchInfo = tractInfo.getPatchInfo(patch)
135  references = lsst.afw.table.SourceCatalog(self.references.schema)
136  references.extend(self.references.fetchInPatches(dataRef, patchList=[patchInfo]))
137  return references
138 
139  def attachFootprints(self, sources, refCat, exposure, refWcs, dataRef):
140  """For coadd forced photometry, we use the deblended HeavyFootprints from the single-band
141  measurements of the same band - because we've guaranteed that the peaks (and hence child sources)
142  will be consistent across all bands before we get to measurement, this should yield reasonable
143  deblending for most sources. It's most likely limitation is that it will not provide good flux
144  upper limits for sources that were not detected in this band but were blended with sources that
145  were.
146  """
147  if self.config.footprintDatasetName is None:
148  return ForcedPhotImageTask.attachFootprints(self, sources, refCat, exposure, refWcs, dataRef)
149  self.log.info("Loading deblended footprints for sources from %s, %s" %
150  (self.config.footprintDatasetName, dataRef.dataId))
151  fpCat = dataRef.get("%sCoadd_%s" % (self.config.coaddName, self.config.footprintDatasetName),
152  immediate=True)
153  for refRecord, srcRecord in zip(refCat, sources):
154  fpRecord = fpCat.find(refRecord.getId())
155  if fpRecord is None:
156  raise LookupError("Cannot find Footprint for source %s; please check that %sCoadd_%s "
157  "IDs are compatible with reference source IDs" %
158  (srcRecord.getId(), self.config.coaddName,
159  self.config.footprintDatasetName))
160  srcRecord.setFootprint(fpRecord.getFootprint())
161 
162  @classmethod
163  def _makeArgumentParser(cls):
164  parser = lsst.pipe.base.ArgumentParser(name=cls._DefaultName)
165  parser.add_id_argument("--id", "deepCoadd_forced_src", help="data ID, with raw CCD keys + tract",
166  ContainerClass=lsst.coadd.utils.CoaddDataIdContainer)
167  return parser
A base class for command-line forced measurement drivers.
def attachFootprints(self, sources, refCat, exposure, refWcs, dataRef)
A command-line driver for performing forced measurement on coadd images.
Config class for forced measurement driver task.