Improve old-style filter translation.

Code will now recognize that filters identified by an afw_name are unlikely to be referred to by any other name.
lsst · Mar 30, 2021 · d2fb979 · d2fb979
1 parent 93d8575
commit d2fb979
Show file tree

Hide file tree

Showing 2 changed files with 14 additions and 10 deletions.
diff --git a/python/lsst/obs/base/cameraMapper.py b/python/lsst/obs/base/cameraMapper.py
@@ -1106,6 +1106,15 @@ def _getBestFilter(self, storedLabel, idFilter):
                 newLabel = list(definitions)[0].makeFilterLabel()
                 return newLabel
             elif definitions:
+                # Some instruments have many filters for the same band, of
+                # which one is known by band name and the others always by
+                # afw name (e.g., i, i2).
+                nonAfw = {f for f in definitions if f.afw_name is None}
+                if len(nonAfw) == 1:
+                    newLabel = list(nonAfw)[0].makeFilterLabel()
+                    self.log.debug("Assuming %r is the correct match.", newLabel)
+                    return newLabel
+
                 self.log.warn("Multiple matches for filter %r with data ID %r.", storedLabel, idFilter)
                 # Can we at least add a band?
                 # Never expect multiple definitions with same physical filter.

diff --git a/tests/test_cameraMapper.py b/tests/test_cameraMapper.py
@@ -416,11 +416,12 @@ def testStandardize(self):
         self.assertEqual(mapper.canStandardize("notPresent"), False)
 
     def testStandardizeFiltersFilterDefs(self):
+        # tuples are (input, desired output)
         testLabels = [
             (None, None),
             (afwImage.FilterLabel(band="i", physical="i.MP9701"),
              afwImage.FilterLabel(band="i", physical="i.MP9701")),
-            (afwImage.FilterLabel(band="i"), afwImage.FilterLabel(band="r", physical="i.MP9701")),
+            (afwImage.FilterLabel(band="i"), afwImage.FilterLabel(band="i", physical="i.MP9701")),
             (afwImage.FilterLabel(physical="i.MP9701"),
              afwImage.FilterLabel(band="i", physical="i.MP9701")),
             (afwImage.FilterLabel(band="i", physical="old-i"),
@@ -437,18 +438,12 @@ def testStandardizeFiltersFilterDefs(self):
         for input, corrected in testLabels:
             for dataId in testIds:
                 if input is None:
-                    if dataId["filter"] == "i":
-                        data = (input, dataId, afwImage.FilterLabel(band="i"))
-                    elif dataId["filter"] == "i2":
+                    if dataId["filter"] == "i2":
                         data = (input, dataId, afwImage.FilterLabel(band="i", physical="HSC-I2"))
                     else:
                         data = (input, dataId, afwImage.FilterLabel(band="i", physical="i.MP9701"))
-                elif input == afwImage.FilterLabel(band="i"):
-                    if dataId["filter"] == "i":
-                        # There are two "i" filters, can't tell which
-                        data = (input, dataId, input)
-                    elif dataId["filter"] == "i2":
-                        data = (input, dataId, afwImage.FilterLabel(band="i", physical="HSC-I2"))
+                elif input == afwImage.FilterLabel(band="i") and dataId["filter"] == "i2":
+                    data = (input, dataId, afwImage.FilterLabel(band="i", physical="HSC-I2"))
                 elif corrected.physicalLabel == "HSC-I2" and dataId["filter"] in ("i.MP9701", "old-i"):
                     # Contradictory inputs, leave as-is
                     data = (input, dataId, input)