Issue #120 Revise NaN pixel handling in clearsky_temperature.py (#274)

* Revise NaN pixel handling in clearsky_temperature.py. Raise specific warning.  Fixes #120

* Changelog update

* rewrite cs tamb test in pytest style

* add test for not-on-land

Co-authored-by: Kevin Anderson <[email protected]>

Author: cdeline

docs/sphinx/source/changelog/pending.rst

@@ -1,5 +1,6 @@
 ************************
 Pending
+
 ************************
 
 API Changes
@@ -32,14 +33,13 @@ Bug fixes
 * Unexpected recoveries when using ``method=random_clean`` in the soiling module
   have been fixed. (:pull:`199`, :issue:`234`)
 
+* Improved NaN pixel handling in
+  :py:func:`~rdtools.clearsky_temperature.get_clearsky_tamb` (:pull:`274`).
 
 Testing
 -------
 
 
-Documentation
--------------
-
 
 Documentation
 -------------

rdtools/clearsky_temperature.py

@@ -85,11 +85,6 @@ def get_clearsky_tamb(times, latitude, longitude, window_size=40,
         day = _get_pixel_value(a, lon_index, lat_index, k, radius)
         night = _get_pixel_value(b, lon_index, lat_index, k, radius)
 
-        if pd.isnull(day):
-            day = a[:, lat_index, k]
-        if pd.isnull(night):
-            night = a[:, lat_index, k]
-
         ave_day.append(day)
         ave_night.append(night)
 
@@ -118,6 +113,9 @@ def solar_noon_offset(utc_offset):
             df['night'].values,
             df['day'].values,
             df['solar_noon_offset'].values)
+    if df['Clear Sky Temperature (C)'].isna().any():
+        warnings.warn("Clear Sky Temperature includes NaNs, "
+                      "possibly invalid Lat/Lon coordinates.", UserWarning)
     return df['Clear Sky Temperature (C)']
 
 

rdtools/test/clearsky_temperature_test.py

@@ -1,39 +1,37 @@
-import unittest
+import pytest
 import pandas as pd
 
 from rdtools.clearsky_temperature import get_clearsky_tamb
 
 
-class ClearSkyTemperatureTestCase(unittest.TestCase):
-    '''Unit tests for clearsky_temperature module'''
+@pytest.fixture
+def china_cs_tamb():
+    dt = pd.date_range('2015-01-01', '2015-02-01', freq='15min', tz='Asia/Shanghai')
+    china_west = get_clearsky_tamb(dt, 37.951721, 80.609843)
+    china_east = get_clearsky_tamb(dt, 36.693692, 117.699686)
+    return china_west, china_east
 
-    def setUp(self):
-
-        dt = pd.date_range('2015-01-01', '2015-02-01', freq='15min', tz='Asia/Shanghai')
-
-        self.china_west = get_clearsky_tamb(dt, 37.951721, 80.609843)
-        self.china_east = get_clearsky_tamb(dt, 36.693692, 117.699686)
-
-        # self.china_west.to_csv("west.csv")
-        # self.china_east.to_csv("east.csv")
 
+def test_hour_offset(china_cs_tamb):
     # Test for shifting temperature peak with longitude for same timezone
-    def test_hour_offset(self):
-
-        df = pd.DataFrame(index=self.china_west.index)
-        df['west'] = self.china_west
-        df['east'] = self.china_east
-        df['hour'] = df.index.hour
+    china_west, china_east = china_cs_tamb
 
-        west_hottest_hour = df.sort_values(by='west', ascending=False)['hour'].iloc[0]
-        east_hottest_hour = df.sort_values(by='east', ascending=False)['hour'].iloc[0]
+    df = pd.DataFrame(index=china_west.index)
+    df['west'] = china_west
+    df['east'] = china_east
+    df['hour'] = df.index.hour
 
-        # print west_hottest_hour , east_hottest_hour
+    west_hottest_hour = df.sort_values(by='west', ascending=False)['hour'].iloc[0]
+    east_hottest_hour = df.sort_values(by='east', ascending=False)['hour'].iloc[0]
 
-        self.assertTrue(west_hottest_hour > 12)
-        self.assertTrue(east_hottest_hour > 12)
-        self.assertTrue(west_hottest_hour > east_hottest_hour)
+    assert west_hottest_hour > 12
+    assert east_hottest_hour > 12
+    assert west_hottest_hour > east_hottest_hour
 
 
-if __name__ == '__main__':
-    unittest.main()
+def test_not_on_land():
+    # test that specifying a point in the ocean returns NaN and warns
+    dt = pd.date_range('2015-01-01', freq='15min', periods=1, tz='UTC')
+    with pytest.warns(UserWarning, match='possibly invalid Lat/Lon coordinates'):
+        ocean_cs_tamb = get_clearsky_tamb(dt, 40, -60)
+    assert ocean_cs_tamb.isnull().all()