Use only stars in internal jointcal fitting

and limit to isolated stars with SNR > 10.
This config shows improvement in the photometric repeatability
and match to the reference catalog.
* Revert to astrometry source selector in unit tests
  that check equality in metrics when jointcal run on testdata.
* Remove some now-redundant config overrides in those
  affected unit tests.

python/lsst/jointcal/jointcal.py

@@ -320,12 +320,28 @@ def validate(self):
             raise pexConfig.FieldValidationError(JointcalConfig.colorterms, self, msg)
 
     def setDefaults(self):
-        sourceSelector = self.sourceSelector["astrometry"]
-        sourceSelector.setDefaults()
-        # don't want to lose existing flags, just add to them.
-        sourceSelector.badFlags.extend(["slot_Shape_flag"])
-        # This should be used to set the FluxField value in jointcal::JointcalControl
-        sourceSelector.sourceFluxType = self.sourceFluxType
+        # Use science source selector which can filter on extendedness, SNR, and whether blended
+        self.sourceSelector.name = 'science'
+        # Use only stars because aperture fluxes of galaxies are biased and depend on seeing
+        self.sourceSelector['science'].doUnresolved = True
+        # with dependable signal to noise ratio.
+        self.sourceSelector['science'].doSignalToNoise = True
+        # Min SNR must be > 0 because jointcal cannot handle negative fluxes,
+        # and S/N > 10 to use sources that are not too faint, and thus better measured.
+        self.sourceSelector['science'].signalToNoise.minimum = 10.
+        # Base SNR on CalibFlux because that is the flux jointcal that fits and must be positive
+        fluxField = f"slot_{self.sourceFluxType}Flux_instFlux"
+        self.sourceSelector['science'].signalToNoise.fluxField = fluxField
+        self.sourceSelector['science'].signalToNoise.errField = fluxField + "Err"
+        # Do not trust blended sources' aperture fluxes which also depend on seeing
+        self.sourceSelector['science'].doIsolated = True
+        # Do not trust either flux or centroid measurements with flags,
+        # chosen from the usual QA flags for stars)
+        self.sourceSelector['science'].doFlags = True
+        badFlags = ['base_PixelFlags_flag_edge', 'base_PixelFlags_flag_saturated',
+                    'base_PixelFlags_flag_interpolatedCenter', 'base_SdssCentroid_flag',
+                    'base_PsfFlux_flag', 'base_PixelFlags_flag_suspectCenter']
+        self.sourceSelector['science'].flags.bad = badFlags
 
 
 class JointcalTask(pipeBase.CmdLineTask):

tests/config/cfht-flagged-config.py

@@ -0,0 +1,5 @@
+config.sourceSelector.name = "flagged"
+# Calib flag names changed with RFC-498 (DM-14997).  The following sets the config to use the
+# old names associated with the current data in testdata_jointcal that was processed pre-RFC-498.
+# Remove line if the data in testdata_jointcal are ever reprocessed post-RFC-498 (e.g. DM-17597)
+config.sourceSelector.active.field = "calib_psfUsed"

tests/config/config.py

@@ -1,2 +1,10 @@
 config.astrometryRefObjLoader.ref_dataset_name = "sdss-dr9-fink-v5b"
 config.photometryRefObjLoader.ref_dataset_name = "sdss-dr9-fink-v5b"
+# TODO DM-17597: Use the astrometrySourceSelector until we redo the refcats and metrics.
+# Once we do that, we can try using the sourceSelector defaults and recompute all
+# the metrics to match, though it may result in problems due to not having enough sources
+# because the testdata is generally fainter than the HSC/LSST data that the defaults
+# are now designed for.
+config.sourceSelector.name = "astrometry"
+config.sourceSelector["astrometry"].sourceFluxType = "Calib"
+config.sourceSelector["astrometry"].badFlags.extend(["slot_Shape_flag", "base_PixelFlags_flag_interpolated"])

tests/test_jointcal_cfht.py

@@ -71,8 +71,6 @@ def test_jointcalTask_2_visits(self):
         self.config.astrometryModel = "simple"
         self.config.photometryModel = "simpleFlux"
 
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
-
         # to test whether we got the expected chi2 contribution files.
         self.other_args.extend(['--config', 'writeChi2FilesInitialFinal=True'])
 
@@ -115,7 +113,6 @@ def setup_jointcalTask_2_visits_constrainedAstrometry(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.astrometryModel = "constrained"
         self.config.doPhotometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_photometry = False
 
         # See Readme for an explanation of these empirical values.
@@ -161,7 +158,6 @@ def setup_jointcalTask_2_visits_constrainedPhotometry(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.photometryModel = "constrainedFlux"
         self.config.doAstrometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_astrometry = False
 
         # See Readme for an explanation of these empirical values.
@@ -211,11 +207,9 @@ def test_jointcalTask_2_visits_constrainedPhotometry_lineSearch(self):
     def test_jointcalTask_2_visits_constrainedPhotometry_flagged(self):
         """Test the use of the FlaggedSourceSelector."""
         pa1, metrics = self.setup_jointcalTask_2_visits_constrainedPhotometry()
-        self.config.sourceSelector.name = "flagged"
-        # Calib flag names changed with RFC-498 (DM-14997).  The following sets the config to use the
-        # old names associated with the current data in testdata_jointcal that was processed pre-RFC-498.
-        # Remove line if the data in testdata_jointcal are ever reprocessed post-RFC-498.
-        self.config.sourceSelector.active.field = "calib_psfUsed"
+        test_config = os.path.join(lsst.utils.getPackageDir('jointcal'),
+                                   'tests/config/cfht-flagged-config.py')
+        self.configfiles.append(test_config)
         # Reduce warnings due to flaggedSourceSelector having fewer sources than astrometrySourceSelector.
         self.config.minMeasuredStarsPerCcd = 30
         self.config.minRefStarsPerCcd = 20

tests/test_jointcal_decam.py

@@ -75,7 +75,6 @@ def test_jointcalTask_2_visits(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.astrometryModel = "simple"
         self.config.photometryModel = "simpleFlux"
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
 
         # See Readme for an explanation of these empirical values.
         # NOTE: the photometry and astrometry refstars numbers are different
@@ -108,7 +107,6 @@ def setup_jointcalTask_2_visits_constrainedAstrometry_no_photometry(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.astrometryModel = "constrained"
         self.config.doPhotometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_photometry = False
 
         # See Readme for an explanation of these empirical values.
@@ -159,7 +157,6 @@ def setup_jointcalTask_2_visits_constrainedPhotometry_no_astrometry(self):
         """
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.photometryModel = "constrainedFlux"
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.config.doAstrometry = False
         self.jointcalStatistics.do_astrometry = False
 

tests/test_jointcal_hsc.py

@@ -71,7 +71,6 @@ def test_jointcalTask_2_visits_simple(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.astrometryModel = "simple"
         self.config.photometryModel = "simpleFlux"
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
 
         # See Readme for an explanation of these empirical values.
         dist_rms_relative = 17e-3*u.arcsecond
@@ -101,7 +100,6 @@ def test_jointcalTask_11_visits_simple_astrometry_no_photometry(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.astrometryModel = "simple"
         self.config.doPhotometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_photometry = False
 
         # See Readme for an explanation of these empirical values.
@@ -124,7 +122,6 @@ def setup_jointcalTask_2_visits_simplePhotometry(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.photometryModel = "simpleFlux"
         self.config.doAstrometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_astrometry = False
 
         # See Readme for an explanation of these empirical values.
@@ -191,7 +188,6 @@ def testJointcalTask_2_visits_simple_astrometry_no_photometry(self):
         self.config = lsst.jointcal.jointcal.JointcalConfig()
         self.config.astrometryModel = "simple"
         self.config.doPhotometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_photometry = False
 
         data_refs = self._testJointcalTask(2, dist_rms_relative, self.dist_rms_absolute,
@@ -206,7 +202,6 @@ def test_jointcalTask_2_visits_simple_astrometry_gaia_refcat(self):
         self.config.astrometryModel = "simple"
         self.config.photometryModel = "simpleFlux"
         # use the a.net refcat for photometry, gaia for astrometry
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         test_config = os.path.join(lsst.utils.getPackageDir('jointcal'), 'tests/config/hsc-gaia-config.py')
         self.configfiles.append(test_config)
         dist_rms_relative = 17e-3*u.arcsecond
@@ -243,7 +238,6 @@ def test_jointcalTask_2_visits_simple_astrometry_no_photometry_match_cut_10(self
         self.config.astrometryModel = "simple"
         self.config.matchCut = 10.0  # TODO: once DM-6885 is fixed, we need to put `*lsst.afw.geom.arcseconds`
         self.config.doPhotometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_photometry = False
 
         # See Readme for an explanation of these empirical values.
@@ -265,7 +259,6 @@ def test_jointcalTask_3_visits_simple_astrometry_no_photometry(self):
         self.config.astrometryModel = "simple"
         self.config.minMeasurements = 2
         self.config.doPhotometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_photometry = False
 
         # See Readme for an explanation of these empirical values.
@@ -289,7 +282,6 @@ def test_jointcalTask_3_visits_simple_astrometry_no_photometry_min_measurements_
         self.config.minMeasurements = 3
         self.config.astrometryModel = "simple"
         self.config.doPhotometry = False
-        self.config.sourceSelector['astrometry'].badFlags.append("base_PixelFlags_flag_interpolated")
         self.jointcalStatistics.do_photometry = False
 
         # See Readme for an explanation of these empirical values.