Best Geocoding Service for iPhone Developers

Question

I have made an app that gets an array of addresses from a web service and I want to map them. I know Apple left this out in MapKit, including only a reverse GeoCoder. I was wondering what the best way to approach this problem was. Web Service? Google Maps API (How do API keys work?)? CloudMade?

What is your opinions on which service is fastest, easiest to use, and cheapest (hopefully free)?

Thanks, Conrad Kramer

Answer 1

I use a "Restful WebService" for Reverse Geocoding using Google Maps and once I get the coordinates I store them in SQLite for later reference. The service returns a JSON string which I later parse in the iPhone.

Something like:

// Initialize call to REST Webservice
- (void) initCall
{
    // Service
    RESTClient *client = [[[RESTClient alloc] initWithDelegate:self] autorelease];
    NSString *serviceHost = @"http://www.site.com/service/maps";
    [client get:serviceHost];
    [serviceHost release];
}

- (void)RESTRequestDidSucceed:(RESTClient*)sender
{

        // Search
   NSString *data = [[[NSString alloc] init] autorelease];
   data = [[NSString alloc] initWithData:sender.receivedData encoding:NSUTF8StringEncoding];

   // Now you have the DATA in and NSString which you can pass as an argument to a method
   // something like

}

Answer 2

IANAL, but if the app you're building will be free, then I believe you can use the Google Maps API for free. It's limited to 15,000 geocoding requests per day, but according to the docs, that's tied to IP, not API key. You can get an API key immediately — no approval required. (If your app will not be freely available then you will have to sign up for Google Maps Premier.)

GMaps now has a REST-based geocoding API over HTTP (it used to be you had to use their JavaScript API, which was a pain on iPhone). It can return in JSON, which is trivial to parse using TouchJSON if you need the extra data, or CSV, which will be even easier if all you need is lat/lon. So, you can just create an object that conforms to the MKAnnotation protocol that will fetch the JSON/CSV from the API using an NSURLConnection or ASIHTTPRequest, parse it, and return the Point variable as the coordinate property and build your MapView as required.

Answer 3

The Google Maps API version 3 doesn't require an API key anymore.

Read this: http://blog.sallarp.com/ipad-iphone-forward-geocoding-api-google/

Answer 4

According to both Google and Yahoo, their respective geocoding services DO NOT allow for "storage for future use." Unless I've misunderstood, you cannot store query results into any form of database. Otherwise it'd be really easy to just Google (now 50,000 requests per day).