ENH: Improve performance for xradar interface (#1621)

pyart/xradar/accessor.py

@@ -275,17 +275,26 @@ def __init__(self, xradar, default_sweep="sweep_0", scan_type=None):
         self.nsweeps = len(self.sweep_group_names)
         self.combined_sweeps = self._combine_sweeps()
         self.fields = self._find_fields(self.combined_sweeps)
+
+        # Check to see if the time is multidimensional - if it is, collapse it
+        if len(self.combined_sweeps.time.dims) > 1:
+            time = self.combined_sweeps.time.isel(range=0)
+        else:
+            time = self.combined_sweeps.time
         self.time = dict(
-            data=(self.combined_sweeps.time - self.combined_sweeps.time.min()).astype(
-                "int64"
-            )
-            / 1e9,
+            data=(time - time.min()).astype("int64").values / 1e9,
             units=f"seconds since {pd.to_datetime(self.combined_sweeps.time.min().values).strftime('%Y-%m-%d %H:%M:%S.0')}",
             calendar="gregorian",
         )
         self.range = dict(data=self.combined_sweeps.range.values)
         self.azimuth = dict(data=self.combined_sweeps.azimuth.values)
         self.elevation = dict(data=self.combined_sweeps.elevation.values)
+        # Check to see if the time is multidimensional - if it is, collapse it
+        if len(self.combined_sweeps.sweep_fixed_angle.dims) > 1:
+            self.combined_sweeps["sweep_fixed_angle"] = (
+                "sweep_number",
+                np.unique(self.combined_sweeps.sweep_fixed_angle),
+            )
         self.fixed_angle = dict(data=self.combined_sweeps.sweep_fixed_angle.values)
         self.antenna_transition = None
         self.latitude = dict(
@@ -590,6 +599,10 @@ def _combine_sweeps(self):
         # Stack the sweep number and azimuth together
         stacked = merged.stack(gates=["sweep_number", "azimuth"]).transpose()
 
+        # Select the valid azimuths
+        good_azimuths = stacked.time.dropna("gates", how="all").gates
+        stacked = stacked.sel(gates=good_azimuths)
+
         # Drop the missing gates
         cleaned = stacked.where(stacked.time == stacked.time.dropna("gates"))