CODEWITHSUNDEEP
phpjquerygoogle-mapsgeolocationgeocoding
Walker
Walker

Reputation: 134721

Converting latitude/longitude into city name? (reverse geolocating)

I'm working on a job board in Codeigniter PHP + jQuery where employers enter their location and we use Google Maps API to plot it. While this has had awesome usability results, the problem is when we try to display these locations to job seekers they are muddled and hard to visually discern (they read like this: "02905, 2 miles away","171 John St., 4 miles away", "Providence, RI, 10 miles away".

I want to be able to reverse geolocate from a longitude/latitude to a set level (ideally, city name) so that in the search results I can have the locations be listed like this: "Providence, RI, 10 miles away", "Providence, RI, 5 miles away", "Cranston, RI, 16 miles away".

Is there a way to reverse geocode to city? I see many examples for ways to reverse geocode to nearest addressable location, but no way to control the level.

Hope that's clear! Feel free to comment with any questions you need clarification on.

Upvotes: 14

Views: 34242

Answers (6)

Kurt Van den Branden
Kurt Van den Branden

Reputation: 12973

Html5 geolocation requires user permission. If you don't want this behaviour, you can go for an external provider like https://geolocation-db.com. They offer a free geolocation service based on ip-addresses.

Try this example:

<!DOCTYPE html>
<html>
<head>
  <title>Geolocation DB - jQuery example</title>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
</head>
<body>
  <div>Country: <span id="country"></span>
  <div>State: <span id="state"></span>
  <div>City: <span id="city"></span>
  <div>Latitude: <span id="latitude"></span>
  <div>Longitude: <span id="longitude"></span>
  <div>IP: <span id="IPv4"></span>
  <script>
    $.ajax({
      url: "https://geolocation-db.com/jsonp",
      jsonpCallback: "callback",
      dataType: "jsonp",
      success: function( location ) {
        $('#country').html(location.country_name);
        $('#state').html(location.state);
        $('#city').html(location.city);
        $('#latitude').html(location.latitude);
        $('#longitude').html(location.longitude);
        $('#ip').html(location.IPv4);  
      }
    });     
  </script>
</body>
</html>

Upvotes: -2

turgos
turgos

Reputation: 1614

I was searching for an API to convert lat/long to city. Seems like this was the original question on this thread as well.

I saw the data "http://download.geonames.org/export/dump/" shared on another stackoverflow thread Given the lat/long coordinates, how can we find out the city/country?, and implemented my own Web Service.

You can see it running at http://scatter-otl.rhcloud.com/location?lat=36&long=-78.9 Just change the latitude and longitude for your locations.

It is deployed on OpenShift (RedHat Platform). First call after a long idle period may take sometime, but usually performance is satisfactory. Feel free to use this service as you like...

Also, you can find the project source at https://github.com/turgos/Location.

Upvotes: 0

Maksym Kozlenko
Maksym Kozlenko

Reputation: 10363

FREE SOURCES (e.g. Creative Commons)

Geonames

If you're looking for free (as freedom) sources, you can use Geonames API findNearbyPlaceName.

For example the following returns nearest Placename:

http://api.geonames.org/findNearbyPlaceName?lat=47.3&lng=9&username=demo

More information is available here

http://www.geonames.org/export/web-services.html#findNearbyPlaceName

Freebase

Instead of single point it takes bounded box. Call sample:

http://api.freebase.com/api/service/geosearch?location=[30.2,50.4,30.6,50.8]&location_type=/location/citytown&inside=true&indent=1

Geocoder.ca

Reverse geocoding for North American addresses.

Info: http://geocoder.ca/

Sample call: http://geocoder.ca/?latt=40.70771000786733&longt=-74.0109443664550&reverse=1&allna=1&geoit=xml&corner=1&jsonp=1&callback=test

Map Quest API

Using Open Street Map nominatim service:

http://open.mapquestapi.com/nominatim/v1/search?q=50.4,30.4&format=json

NON FREE SOURCES

Yahoo PlaceFinder

Documentation http://developer.yahoo.com/geo/placefinder/

Sample call:

http://where.yahooapis.com/geocode?q=38.898717,+-77.035974&gflags=R&appid=[yourappidhere]

Google Maps API

Documentation:

http://code.google.com/apis/maps/documentation/geocoding/#ReverseGeocoding

Upvotes: 37

James D
James D

Reputation: 1506

Reverse geocoding services (such as Google, Yahoo, and GeoNames) will work well for this purpose with a few caveats:

  • Although I can't say for sure how the commercial services work, last time I checked GeoNames uses a closest point of interest strategy to determine the city. This can be a problem if your query point is somewhat near a border between two cities and the nearest entry in the GeoNames database is on the other side of that border. This actually happens a fair bit in my experience, so this is not just some technicality.
  • Also, if you are concerned about user experience, any web API solution adds latency and reduces reliability.

I run a web site that offers a number of commercial geographic web APIs, and sells the Java libraries that we built to back those APIs. One of them (which only has US coverage) uses a proper polygonal map of the cities and towns in the US to return the result that contains your query point. It is accurate and fast, so if this is a mission critical component in your system, I suggest taking a look at our web site:

http://askgeo.com

The page that is specific to looking up cities from lat/lon is:

http://askgeo.com/database/UsPlace2010

Upvotes: 0

Ossama
Ossama

Reputation: 2417

The Google Geocoder, which supports reverse geocoding returns address_components. You just need to pull out the component of the address tagged with locality and political if you just want the city name. If you want states as well they are tagged with administrative_area_level_1

Upvotes: 12

zebediah49
zebediah49

Reputation: 7611

Can't you just do it do full address, and then drop the street and number?

I would say it'd be more valuable to use the full address, so as to get a more accurate distance (even if you only display the city,state).

EDIT: If you do do it that way, at least it should be returned in a standard form, which you can then easily regex the data you want out of.

Upvotes: 2

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