Google Geocoder Lookup get postal code by country and city

Question

I'm currently using Google Geocoder API to determine location data for my web service. It's important for me to get the postal code for a given country and city, but it's look like that Google is limiting the result.

Here's the API call:

http://maps.googleapis.com/maps/api/geocode/json?address=deutschland,+saarlouis&language=de&sensor=false

The result is like that:

{
   "results" : [
      {
         "address_components" : [
            {
               "long_name" : "Saarlouis",
               "short_name" : "Saarlouis",
               "types" : [ "locality", "political" ]
            },
            {
               "long_name" : "Landkreis Saarlouis",
               "short_name" : "Landkreis Saarlouis",
               "types" : [ "administrative_area_level_3", "political" ]
            },
            {
               "long_name" : "Saarland",
               "short_name" : "SL",
               "types" : [ "administrative_area_level_1", "political" ]
            },
            {
               "long_name" : "Deutschland",
               "short_name" : "DE",
               "types" : [ "country", "political" ]
            }
         ],
         "formatted_address" : "Saarlouis, Deutschland",
         "geometry" : {
            "bounds" : {
               "northeast" : {
                  "lat" : 49.36187570,
                  "lng" : 6.815549499999999
               },
               "southwest" : {
                  "lat" : 49.26046930,
                  "lng" : 6.67501510
               }
            },
            "location" : {
               "lat" : 49.31346060,
               "lng" : 6.752286499999999
            },
            "location_type" : "APPROXIMATE",
            "viewport" : {
               "northeast" : {
                  "lat" : 49.36187570,
                  "lng" : 6.815549499999999
               },
               "southwest" : {
                  "lat" : 49.26046930,
                  "lng" : 6.67501510
               }
            }
         },
         "types" : [ "locality", "political" ]
      }
   ],
   "status" : "OK"
}

Answer 1

The reason you don't get the postal code is the query is too broad. If you would add a street name to the query the result will contain a postal code. A solution to your problem if you don't have a street name or don't want to use it is to split the geocoding into two parts:

Step 1: Use the city to get the GPS coordinates

https://maps.googleapis.com/maps/api/geocode/json?address=amsterdam

Step 2: Use the the GPS coordidates to get the postal code

https://maps.googleapis.com/maps/api/geocode/json?latlng=52.3182742,4.7288558

---

For those doing it in backend/script, here is a snippet: (using python Geocoder)

g = geocoder.google(city, key=google_api_key)
latlng = g.latlng
g_prime = geocoder.google("{},{}".format(*latlng), key=google_api_key)
postal_code = g_prime.postal

Answer 2

Using the Official Drag Markers Geocoder - you have German Postcodes displayed.

http://gmaps-samples-v3.googlecode.com/svn/trunk/draggable-markers/draggable-markers.html

(zoom to Germany or change the source code and set the bounds to Germany)

Answer 3

The Google Geocoding API has usage limits.

Use of the Google Geocoding API is subject to a query limit of 2,500 geolocation requests per day. (User of Google Maps API for Business may perform up to 100,000 requests per day.) This limit is enforced to prevent abuse and/or repurposing of the Geocoding API, and this limit may be changed in the future without notice. Additionally, we enforce a request rate limit to prevent abuse of the service. If you exceed the 24-hour limit or otherwise abuse the service, the Geocoding API may stop working for you temporarily. If you continue to exceed this limit, your access to the Geocoding API may be blocked.

You might want to try setting up your own geocoder using Gisgraphy or something similar. That way you won't be affected by usage limits.