Why does geolocate not give me the right addresses?

Question

So I was analyzing a data set with addresses in Philadelphia, PA. Now, in order to make use of these, I wanted to get the exact longitude and latitude to later show them on a map.

I have gotten the unique entries of the column as a list and have implemented a loop to get me the longitude and latitude, though it's giving me the same coordinates for every city and sometimes even ones that are outside of Philadelphia.

Here's what I did so far:

from geopy.geocoders import Nominatim

geolocator = Nominatim(user_agent="my_user_agent")
geocode = lambda query: geolocator.geocode("%s, Philadelphia PA" % query)

cities = list(philly["station_name"].unique())
for city in cities:
    address = city
    location = geolocator.geocode(address)
    if(location != None):
        philly["longitude"] = location.longitude
        philly["latitude"] = location.latitude

philly["coordinates"] = list(zip(philly["latitude"], philly["longitude"]))

Answer 1

If "philly" is a list of dictionary objects then you can iterate over the list and add the location properties to each record.

from geopy.geocoders import Nominatim

philly = [{'station_name': '30th Street Station'}]

geolocator = Nominatim(user_agent="my_user_agent")
for row in philly:
    address = row["station_name"]
    location = geolocator.geocode(f"{address}, Philadelphia, PA", country_codes="us")
    if location:
        print(address)
        print(">>", location.longitude, location.latitude)
        row["longitude"] = location.longitude
        row["latitude"] = location.latitude
        row["coordinates"] = (location.longitude, location.latitude)
print(philly)

Output:

30th Street Station
>> -75.1821442 39.9552836
[{'station_name': '30th Street Station', 'longitude': -75.1821442, 'latitude': 39.9552836, 'coordinates': (-75.1821442, 39.9552836)}]

If working with a Pandas dataframe then you can iterate over each record in the dataframe then set the latitude, longitude and coordinates fields in it.

You can do something like this:

from geopy.geocoders import Nominatim
import pandas as pd

geolocator = Nominatim(user_agent="my_user_agent")

philly = [{'station_name': '30th Street Station'}]
df = pd.DataFrame(philly)

# add empty location columns to data frame
df["latitude"] = ""
df["longitude"] = ""
df["coordinates"] = ""

for _, row in df.iterrows():
    address = row.station_name
    location = geolocator.geocode(f"{address}, Philadelphia, PA", country_codes="us")
    if location:
        row["latitude"] = location.latitude
        row["longitude"] = location.longitude
        row["coordinates"] = (location.longitude, location.latitude)
print(df)

Output:

          station_name   latitude  longitude                coordinates
0  30th Street Station  39.955284 -75.182144  (-75.1821442, 39.9552836)

If you have a list with duplicate station names then you should cache the results so you don't make duplicate geolocation requests.