DOC: Add docs for using xradar and Py-ART together (#1469)

* DOC: Add docs for xradar and Py-ART

* DOC: Add docs on using xradar with Py-ART

* FIX: Fix small bugs

doc/environment.yml

@@ -33,6 +33,7 @@ dependencies:
   - sphinx-copybutton
   - nbsphinx
   - pre_commit
+  - cmweather
   - pip
   - pip:
       - pooch

examples/xradar/README.txt

@@ -0,0 +1,6 @@
+.. _xradar_examples:
+
+Xradar Examples
+------------------
+
+Examples of using Xradar with Py-ART to accomplish different tasks.

examples/xradar/plot_xradar.py

@@ -0,0 +1,30 @@
+"""
+==================================
+Plot a PPI Using Xradar and Py-ART
+==================================
+
+An example which uses xradar and Py-ART to create a PPI plot of a Cfradial file.
+
+"""
+
+# Author: Max Grover ([email protected])
+# License: BSD 3 clause
+
+
+import xradar as xd
+
+import pyart
+from pyart.testing import get_test_data
+
+# Locate the test data and read in using xradar
+filename = get_test_data("swx_20120520_0641.nc")
+tree = xd.io.open_cfradial1_datatree(filename)
+
+# Give the tree Py-ART radar methods
+radar = pyart.xradar.Xradar(tree)
+
+# Plot the Reflectivity Field (corrected_reflectivity_horizontal)
+display = pyart.graph.RadarMapDisplay(radar)
+display.plot_ppi(
+    "corrected_reflectivity_horizontal", cmap="ChaseSpectral", vmin=-20, vmax=70
+)

pyart/xradar/accessor.py

@@ -17,12 +17,11 @@
 
 
 class Xradar:
-    def __init__(self, xradar, default_sweep="sweep_0"):
+    def __init__(self, xradar, default_sweep="sweep_0", scan_type=None):
         self.xradar = xradar
-        self.scan_type = "ppi"
+        self.scan_type = scan_type or "ppi"
         self.combined_sweeps = self._combine_sweeps(self.xradar)
         self.fields = self._find_fields(self.combined_sweeps)
-        self.scan_type = None
         self.time = dict(
             data=(self.combined_sweeps.time - self.combined_sweeps.time.min()).astype(
                 "int64"
@@ -196,8 +195,9 @@ def get_field(self, sweep, field_name, copy=False):
         data : array
             Array containing data for the requested sweep and field.
         """
-        data = self.xradar[f"sweep_{sweep}"][field_name].values
-
+        self.check_field_exists(field_name)
+        s = self.get_slice(sweep)
+        data = self.fields[field_name]["data"][s]
         if copy:
             return data.copy()
         else:
@@ -256,9 +256,9 @@ def get_gate_x_y_z(self, sweep, edges=False, filter_transitions=False):
         """
         # Check to see if the data needs to be georeferenced
         if "x" not in self.xradar[f"sweep_{sweep}"].coords:
-            self.xradar = self.xradar.xradar.georeference()
+            self.combined_sweeps = self.combined_sweeps.xradar.georeference()
 
-        data = self.xradar[f"sweep_{sweep}"].xradar.georeference()
+        data = self.combined_sweeps.sel(sweep_number=sweep)
         return data["x"].values, data["y"].values, data["z"].values
 
     def init_gate_x_y_z(self):

tests/xradar/test_accessor.py

@@ -15,7 +15,7 @@ def test_get_field(filename=filename):
     )
     radar = pyart.xradar.Xradar(dtree)
     reflectivity = radar.get_field(0, "DBZ")
-    assert reflectivity.shape == (483, 996)
+    assert reflectivity.shape == (480, 996)
 
 
 def test_get_gate_x_y_z(filename=filename):
@@ -25,9 +25,9 @@ def test_get_gate_x_y_z(filename=filename):
     )
     radar = pyart.xradar.Xradar(dtree)
     x, y, z = radar.get_gate_x_y_z(0)
-    assert x.shape == (483, 996)
-    assert y.shape == (483, 996)
-    assert z.shape == (483, 996)
+    assert x.shape == (480, 996)
+    assert y.shape == (480, 996)
+    assert z.shape == (480, 996)
 
 
 def test_add_field(filename=filename):