modified GCoder to detect "not found" cases, added DCalc

src/dcalc.py

@@ -0,0 +1,77 @@
+# DCalc.py: basic test of distance calculation from the Boulder office
+
+import sys
+import argparse
+import json
+import math
+import configparser
+import urllib.parse
+import urllib.request
+
+
+class GeocodingError(RuntimeError):
+    pass
+
+
+def geocode_google(config, address):
+    apikey = config['google']['apikey']
+    if not apikey:
+        raise GeocodingError("Google API key not specified")
+    query = { 'key': apikey, 'address': address, 'region': 'us'}
+    url = 'https://maps.googleapis.com/maps/api/geocode/json?' + \
+          urllib.parse.urlencode(query, quote_via=urllib.parse.quote)
+    with urllib.request.urlopen(url) as response:
+        if response.status == 200:
+            apireturn = json.loads(response.read())
+            stat = apireturn['status']
+            if stat == 'OK':
+                results = apireturn['results']
+                if len(results) > 1:
+                    raise GeocodingError(f"Google API returned ambiguous results (total count {len(results)})")
+                coords = results[0]['geometry']['location']
+                return coords['lat'], coords['lng']
+            elif stat == 'ZERO_RESULTS':
+                return None
+            else:
+                raise GeocodingError(f"Google API returns status of {stat}")
+        else:
+            raise GeocodingError(f"Google API returns {response.status} HTTP status code")
+
+
+OFFICE_LOCATION = (40.0187905, -105.2764775)  # office location - 1433 Pearl Street, Boulder, CO
+RADIUS = 6371.0 * 1000.0                      # Earth radius in meters
+METERS_PER_MILE = 1852.0                      # number of meters per mile
+
+
+def distance_miles(point1, point2):
+    Φ1 = math.radians(point1[0])
+    Φ2 = math.radians(point2[0])
+    ΔΦ = math.radians(point2[0] - point1[0])
+    Δλ = math.radians(point2[1] - point1[1])
+    a = math.sin(ΔΦ / 2.0) * math.sin(ΔΦ / 2.0) + math.cos(Φ1) * math.cos(Φ2) * math.sin(Δλ / 2.0) * math.sin(Δλ / 2.0)
+    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1.0 - a))
+    return RADIUS * c / METERS_PER_MILE
+
+
+cmdline_parser = argparse.ArgumentParser()
+cmdline_parser.add_argument('address', nargs='+', help='The address to be calculated')
+cmdline_parser.add_argument('-C', '--config', default='geoapi.ini', help='The geocoding API configuration file')
+
+
+def main(args):
+    opts = cmdline_parser.parse_args(args)
+    config = configparser.ConfigParser()
+    config.read(opts.config)
+    my_address = ' '.join(opts.address)
+    print(f"Address: '{my_address}'")
+    coords = geocode_google(config, my_address)
+    if coords:
+        print(f"Coordinates: Latitude {coords[0]}, longitude {coords[1]}")
+        dist = distance_miles(OFFICE_LOCATION, coords)
+        print(f"Distance from Boulder office: {dist} miles")
+    else:
+        print("Location was not found.")
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))

src/gcoder.py

@@ -29,6 +29,8 @@ def geocode_google(config, address):
                     raise GeocodingError(f"Google API returned ambiguous results (total count {len(results)})")
                 coords = results[0]['geometry']['location']
                 return coords['lat'], coords['lng']
+            elif stat == 'ZERO_RESULTS':
+                return None
             else:
                 raise GeocodingError(f"Google API returns status of {stat}")
         else:
@@ -112,7 +114,10 @@ def main(args):
     my_address = ' '.join(opts.address)
     print(f"Address: '{my_address}'")
     coords = geocoding_procs[opts.geocoder](config, my_address)
+    if coords:
         print(f"Coordinates: Latitude {coords[0]}, longitude {coords[1]}")
+    else:
+        print("Location was not found.")
 
 
 if __name__ == '__main__':