DM-52677: Add functors for trailLengthErr and trailAngleErr

python/lsst/pipe/tasks/functors.py

@@ -28,6 +28,7 @@
            "ComputePixelScale", "ConvertPixelToArcseconds",
            "ConvertPixelSqToArcsecondsSq",
            "ConvertDetectorAngleToPositionAngle",
+           "ConvertDetectorAngleErrToPositionAngleErr",
            "ReferenceBand", "Photometry",
            "NanoJansky", "NanoJanskyErr", "LocalPhotometry", "LocalNanojansky",
            "LocalNanojanskyErr", "LocalDipoleMeanFlux",
@@ -1554,6 +1555,28 @@ def _func(self, df):
         )
 
 
+class ConvertDetectorAngleErrToPositionAngleErr(Functor):
+    """Convert a detector angle error to a position angle error.
+
+    Returns
+    -------
+    position angle error : degrees
+    """
+
+    name = "PositionAngleErr"
+
+    def __init__(self, theta_err_col, **kwargs):
+        self.theta_err_col = theta_err_col
+        super().__init__(**kwargs)
+
+    @property
+    def columns(self):
+        return [self.theta_err_col]
+
+    def _func(self, df):
+        return np.rad2deg(df[self.theta_err_col])
+
+
 class ReferenceBand(Functor):
     """Return the band used to seed multiband forced photometry.
 
@@ -1992,14 +2015,7 @@ def _func(self, df):
 
 
 class MomentsBase(Functor):
-    """Base class for functors that use shape moments and localWCS
-
-    Attributes
-    ----------
-    is_covariance : bool
-        Whether the shape columns are terms of a covariance matrix. If False,
-        they will be assumed to be terms of a correlation matrix instead.
-    """
+    """Base class for functors that use shape moments and localWCS"""
 
     is_covariance: bool = True
 

tests/test_functors.py

@@ -53,8 +53,8 @@
                                       MomentsG1Sky, MomentsG2Sky, MomentsTraceSky,
                                       CorrelationIuuSky, CorrelationIvvSky, CorrelationIuvSky,
                                       SemimajorAxisFromCorrelation, SemiminorAxisFromCorrelation,
-                                      PositionAngleFromCorrelation
-                                      )
+                                      PositionAngleFromCorrelation,
+                                      ConvertDetectorAngleErrToPositionAngleErr)
 
 ROOT = os.path.abspath(os.path.dirname(__file__))
 
@@ -763,6 +763,19 @@ def testConvertDetectorAngleToPositionAngle(self):
 
                     np.testing.assert_allclose(coord_diff, 0, rtol=0, atol=5e-6)
 
+    # Test position angle error
+    def testConvertDetectorAngleErrToPositionAngleErr(self):
+        """Test conversion of detector angle error in radians to position angle error in degrees."""
+        theta_err_values = np.random.uniform(0, np.pi / 4, size=self.nRecords)
+        self.dataDict["theta_err"] = theta_err_values
+        df = self.getSimpleDataFrame(self.dataDict)
+
+        func = ConvertDetectorAngleErrToPositionAngleErr("theta_err")
+        val = self._funcVal(func, df)
+
+        expected = np.rad2deg(theta_err_values)
+        np.testing.assert_allclose(val.values, expected, rtol=0, atol=1e-13)
+
     def testConvertPixelToArcseconds(self):
         """Test calculations of the pixel scale, conversions of pixel to
         arcseconds.