Catch geocoding erros and fill with empty rows

Catch GeocoderResultError and ValueError. Fill the resulting GeoDataFrame
with an empty row.

geopandas/geocode.py

@@ -2,6 +2,7 @@ from collections import defaultdict
 
 import fiona
 import geopy
+from geopy.geocoders.base import GeocoderResultError
 import numpy as np
 import pandas as pd
 from shapely.geometry import Point
@@ -51,8 +52,10 @@ def geocode(strings, provider='googlev3', **kwargs):
     coder = coders[provider](**kwargs)
     results = {}
     for i, s in strings.iteritems():
-        # Probably want some try/catch here, but what to do on exception?
-        results[i] = coder.geocode(s)
+        try:
+            results[i] = coder.geocode(s)
+        except (GeocoderResultError, ValueError):
+            results[i] = (None, None)
 
     df = _prepare_geocode_result(results)
     return df
@@ -73,7 +76,14 @@ def _prepare_geocode_result(results):
         address, loc = s
 
         # loc is lat, lon and we want lon, lat
-        p = Point(loc[1], loc[0])
+        if loc is None:
+            p = Point()
+        else:
+            p = Point(loc[1], loc[0])
+
+        if address is None:
+            address = pd.np.nan
+
         d['geometry'].append(p)
         d['address'].append(address)
         index.append(i)

tests/test_geocode.py

@@ -1,6 +1,7 @@
 import unittest
 
 import fiona
+import pandas as pd
 from shapely.geometry import Point
 import geopandas as gpd
 
@@ -32,5 +33,20 @@ class TestGeocode(unittest.TestCase):
         self.assertAlmostEqual(coords[0], test[1])
         self.assertAlmostEqual(coords[1], test[0])
 
+    def test_prepare_result_none(self):
+        p0 = Point(12.3, -45.6) # Treat these as lat/lon
+        d = {'a': ('address0', p0.coords[0]),
+             'b': (None, None)}
+
+        df = _prepare_geocode_result(d)
+        assert type(df) is gpd.GeoDataFrame
+        self.assertEqual(fiona.crs.from_epsg(4326), df.crs)
+        self.assertEqual(len(df), 2)
+        self.assert_('address' in df)
+
+        row = df.loc['b']
+        self.assertEqual(len(row['geometry'].coords), 0)
+        self.assert_(pd.np.isnan(row['address']))
+    
     def test_bad_provider(self):
         self.assertRaises(ValueError, geocode, ['cambridge, ma'], 'badprovider')