Add tests for and fix winds.

aosstower/model.py

@@ -7,6 +7,7 @@ import numpy as np
 from .time import to_unix_timestamp
 from .wind import mean_wind_vector_degrees
 
+
 def dewpoint(tempC, relhum):
     """
     Algorithm from Tom Whittaker tempC is the temperature in degrees Celsius,

aosstower/tests/test_wind.py

 import unittest
 
 
-class MeanVectorAverageTests(unittest.TestCase):
+class MeanWindVectorTests(unittest.TestCase):
 
-    def _fut(self, input_windspd, input_winddir):
+    def _fut(self, winddir, windspd=None):
         from aosstower.wind import mean_wind_vector
-
-        return mean_wind_vector(input_windspd, input_winddir)
-
-    def test_scalar_input(self):
-
-        for wdir, wspd in [(0, 20), (90, 20), (180, 20), (270, 20)]:
-            output_speed, output_dir = self._fut(wspd, wdir)
-            self.assertEqual(wdir, output_dir)
-            self.assertEqual(wspd, 20)
-
-    def test_array_input(self):
-
-        for wdir, wspd in [([0, 90, 180, 270],[10, 10, 10, 10])]:
-            output_speed, output_winddir = self._fut(wspd, wdir)
-            self.assertEqual(wdir, output_winddir.tolist())
-            self.assertEqual(wspd, output_speed.tolist())
+        windspd = windspd or [1]*len(winddir)
+        return mean_wind_vector(windspd, winddir)[0]
+
+    def test_spanning_0_degrees(self):
+        winddir = self._fut([315, 45])
+        self.assertAlmostEqual(winddir, 0)
+
+    def test_spanning_cardinal_directions(self):
+        self.assertAlmostEqual(self._fut([45, 135]), 90)
+        self.assertAlmostEqual(self._fut([135, 225]), 180)
+        self.assertAlmostEqual(self._fut([225, 315]), 270)
+        self.assertAlmostEqual(self._fut([315, 45]), 0)
+
+    def test_all_zeros(self):
+        self.assertAlmostEqual(self._fut([0, 0]), 0)
+
+    def test_zero_windspd(self):
+        self.assertAlmostEqual(self._fut([0, 0], windspd=[0, 0]), 0)
+
+    def test_45s(self):
+        self.assertAlmostEqual(self._fut([0, 90]), 45)
+        self.assertAlmostEqual(self._fut([90, 180]), 135)
+        self.assertAlmostEqual(self._fut([180, 270]), 225)
+        self.assertAlmostEqual(self._fut([270, 0]), 315)

aosstower/wind.py

-
+"""
+See: Campbell Scientific CR1000 Manual Section 7.8.5.2.2.
+"""
 import numpy as np
 
 
-def mean_wind_vector_components(windspd, winddir):
+def wind_vector_components(windspd, winddir):
     """Decompose scalar or list/array wind direction and speed data into the
     corresponding horizontal and vertical direction components and speed
     vector.
+
+    Inputs can be scalar or arrays.
     """
     dir_rad = np.deg2rad(winddir)
-    V_e = windspd * np.sin(dir_rad)
-    V_n = windspd * np.cos(dir_rad)
-    U_spd = (V_e**2 + V_n**2)**0.5
+    spd_arr = np.array(windspd)
+    V_e = spd_arr * np.sin(dir_rad)
+    V_n = spd_arr * np.cos(dir_rad)
+    U_spd = np.sqrt(pow(V_e, 2) + pow(V_n, 2))
     return V_e, V_n, U_spd
 
 
-def mean_wind_vector_degrees(vector_east, vector_north):
+def wind_vector_degrees(vector_east, vector_north):
     """Re-compose horizontal (east/west) and vertical (north/south) vector
     components into wind direction in degrees.
+
+    Inputs can be scalar or arrays.
     """
     rads = np.arctan2(vector_east, vector_north)
     winddir = np.rad2deg(rads)
@@ -24,14 +31,11 @@ def mean_wind_vector_degrees(vector_east, vector_north):
         winddir[np.less(winddir, 0)] += 360
     elif winddir < 0:
         winddir += 360
-    return winddir
+    return winddir % 360
 
 
 def mean_wind_vector(windspd, winddir):
-    """Compute the mean wind vector.
+    V_e, V_n, V_spd = wind_vector_components(windspd, winddir)
+    avg_dir = wind_vector_degrees(np.mean(V_e), np.mean(V_n))
 
-    See: Campbell Scientific CR1000 Manual Section 7.8.5.2.2.
-    """
-    vector_east, vector_north, vector_speed = \
-        mean_wind_vector_components(windspd, winddir)
-    return vector_speed, mean_wind_vector_degrees(vector_east, vector_north)
\ No newline at end of file
+    return avg_dir, np.mean(V_spd)