Alternative to Google Maps Geolocation API

You can use a service provided by Yahoo called YQL. This service is free for a limited number of requests, up to 100,000 per day. Then you can retrieve the latitude and longitude out of the response XML at query/results/place/centroid.

One thing I've noticed with this service is the city names need to be exact, and it is possible for there to be multiple results.

http://developer.yahoo.com/yql/

Example YQL query:

http://query.yahooapis.com/v1/public/yql?q=SELECT * FROM geo.places WHERE text="Seattle" and placeTypeName = "Town"

Response XML:

<?xml version="1.0" encoding="UTF-8"?><query xmlns:yahoo="http://www.yahooapis.com/v1/base.rng" yahoo:count="1" yahoo:created="2012-07-09T16:20:40Z" yahoo:lang="en-US">  <results>    <place xmlns="http://where.yahooapis.com/v1/schema.rng" xml:lang="en-US" yahoo:uri="http://where.yahooapis.com/v1/place/2490383">      <woeid>2490383</woeid>      <placeTypeName code="7">Town</placeTypeName>      <name>Seattle</name>      <country code="US" type="Country">United States</country>      <admin1 code="US-WA" type="State">Washington</admin1>      <admin2 code="" type="County">King</admin2>      <admin3/>      <locality1 type="Town">Seattle</locality1>      <locality2/>      <postal/>      <centroid>        <latitude>47.603561</latitude>        <longitude>-122.329437</longitude>      </centroid>      <boundingBox>        <southWest>          <latitude>47.422359</latitude>          <longitude>-122.472153</longitude>        </southWest>        <northEast>          <latitude>47.745071</latitude>          <longitude>-122.176193</longitude>        </northEast>      </boundingBox>      <areaRank>6</areaRank>      <popRank>12</popRank>    </place>  </results></query><!-- total: 82 --><!-- engine5.yql.mud.yahoo.com -->

Have a look at datasciencetoolkit.org. They offer a VM image/AMI that you can host on EC2 and make geolocation calls to your own server and hence no API limits.

Then there's also Yahoo's geolocation API which has higher limits than Google's.

Usually when you're dealing with a large number of data points, you'd geocode them once on the server. Then you can stream the lat/longs to your clients ready to use.

Google has a Geocoding web service you can use from your server, but there's a request limit of 2,500/day. If that won't work, you can also look in to OSM's Nominatim; Mapquest hosts a web service with no limits.