ADD: Add to_radar() method to xradar objects (#1622)

* ADD: Add to_radar() method

* FIX: Fix the examples to use new to_radar() interface

examples/xradar/plot_dealias_xradar.py

@@ -23,7 +23,7 @@
 tree = xd.io.open_cfradial1_datatree(filename)
 
 # Give the tree Py-ART radar methods
-radar = pyart.xradar.Xradar(tree)
+radar = tree.pyart.to_radar()
 
 # Determine the nyquist velocity using the maximum radial velocity from the first sweep
 nyq = radar["sweep_0"]["mean_doppler_velocity"].max().values

examples/xradar/plot_grid_xradar.py

@@ -21,7 +21,7 @@
 tree = xd.io.open_cfradial1_datatree(filename)
 
 # Give the tree Py-ART radar methods
-radar = pyart.xradar.Xradar(tree)
+radar = tree.pyart.to_radar()
 
 # Grid using 11 vertical levels, and 101 horizontal grid cells at a resolution on 1 km
 grid = pyart.map.grid_from_radars(

examples/xradar/plot_xradar.py

@@ -21,7 +21,7 @@
 tree = xd.io.open_cfradial1_datatree(filename)
 
 # Give the tree Py-ART radar methods
-radar = pyart.xradar.Xradar(tree)
+radar = tree.pyart.to_radar()
 
 # Plot the Reflectivity Field (corrected_reflectivity_horizontal)
 display = pyart.graph.RadarMapDisplay(radar)

pyart/xradar/accessor.py

@@ -5,12 +5,14 @@
 
 import copy
 
+import datatree
 import numpy as np
 import pandas as pd
 from datatree import DataTree, formatting, formatting_html
 from datatree.treenode import NodePath
 from xarray import DataArray, Dataset, concat
 from xarray.core import utils
+from xradar.accessors import XradarAccessor
 from xradar.util import get_sweep_keys
 
 from ..config import get_metadata
@@ -591,7 +593,11 @@ def _combine_sweeps(self):
         # Loop through and extract the different datasets
         ds_list = []
         for sweep in self.sweep_group_names:
-            ds_list.append(self.xradar[sweep].ds.drop_duplicates("azimuth"))
+            ds_list.append(
+                self.xradar[sweep]
+                .ds.drop_duplicates("azimuth")
+                .set_coords("sweep_number")
+            )
 
         # Merge based on the sweep number
         merged = concat(ds_list, dim="sweep_number")
@@ -800,3 +806,23 @@ def _point_altitude_data():
         return grid.origin_altitude["data"][0] + grid.point_z["data"]
 
     return _point_altitude_data
+
+
+@datatree.register_datatree_accessor("pyart")
+class XradarDataTreeAccessor(XradarAccessor):
+    """Adds a number of pyart specific methods to datatree.DataTree objects."""
+
+    def to_radar(self, scan_type=None) -> DataTree:
+        """
+        Add pyart radar object methods to the xradar datatree object
+        Parameters
+        ----------
+        scan_type: string
+            Scan type (ppi, rhi, etc.)
+        Returns
+        -------
+        dt: datatree.Datatree
+            Datatree including pyart.Radar methods
+        """
+        dt = self.xarray_obj
+        return Xradar(dt, scan_type=scan_type)

tests/xradar/test_accessor.py

@@ -154,3 +154,16 @@ def test_grid_write_read():
         assert grid1.radar_name["data"] == grid2.radar_name["data"]
         assert grid1.nradar == grid2.nradar
         grid2.ds.close()
+
+
+def test_to_xradar_object():
+    """Test the to_radar_object"""
+    dtree = xd.io.open_cfradial1_datatree(
+        filename,
+        optional=False,
+    )
+    radar = dtree.pyart.to_radar()
+    reflectivity = radar.get_field(0, "DBZ")
+    assert reflectivity.shape == (480, 996)
+    assert radar.nsweeps == 9
+    assert radar.ngates == 996