Get latitude/longitude from address - ios

Question

How can I get latitude and longitude from a full address (street, city, etc.) input by the user, using the iPhone SDK 3.x?

Answer 1

Here's an updated, more compact, version of unforgiven's code, which uses the latest v3 API:
- (CLLocationCoordinate2D) geoCodeUsingAddress:(NSString *)address
{
double latitude = 0, longitude = 0;
NSString *esc_addr = [address stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *req = [NSString stringWithFormat:#"http://maps.google.com/maps/api/geocode/json?sensor=false&address=%#", esc_addr];
NSString *result = [NSString stringWithContentsOfURL:[NSURL URLWithString:req] encoding:NSUTF8StringEncoding error:NULL];
if (result) {
NSScanner *scanner = [NSScanner scannerWithString:result];
if ([scanner scanUpToString:#"\"lat\" :" intoString:nil] && [scanner scanString:#"\"lat\" :" intoString:nil]) {
[scanner scanDouble:&latitude];
if ([scanner scanUpToString:#"\"lng\" :" intoString:nil] && [scanner scanString:#"\"lng\" :" intoString:nil]) {
[scanner scanDouble:&longitude];
}
}
}
CLLocationCoordinate2D center;
center.latitude = latitude;
center.longitude = longitude;
return center;
}
It makes the assumption that the coordinates for "location" come first, e.g. before those for "viewport", because it just takes the first coords it finds under the "lng" and "lat" keys. Feel free to use a proper JSON scanner (e.g. SBJSON) if you are worried about this simple scanning technique used here.

Answer 2

You can use Google Geocoding for this. It is as simple as getting data through HTTP and parsing it (it can return JSON KML, XML, CSV).

Answer 3

Here's a similar solution for obtaining the latitude and longitude from Google. Note: This example uses the SBJson library, which you can find on github:
+ (CLLocationCoordinate2D) geoCodeUsingAddress: (NSString *) address
{
CLLocationCoordinate2D myLocation;
// -- modified from the stackoverflow page - we use the SBJson parser instead of the string scanner --
NSString *esc_addr = [address stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding];
NSString *req = [NSString stringWithFormat: #"http://maps.google.com/maps/api/geocode/json?sensor=false&address=%#", esc_addr];
NSDictionary *googleResponse = [[NSString stringWithContentsOfURL: [NSURL URLWithString: req] encoding: NSUTF8StringEncoding error: NULL] JSONValue];
NSDictionary *resultsDict = [googleResponse valueForKey: #"results"]; // get the results dictionary
NSDictionary *geometryDict = [ resultsDict valueForKey: #"geometry"]; // geometry dictionary within the results dictionary
NSDictionary *locationDict = [ geometryDict valueForKey: #"location"]; // location dictionary within the geometry dictionary
// -- you should be able to strip the latitude & longitude from google's location information (while understanding what the json parser returns) --
DLog (#"-- returning latitude & longitude from google --");
NSArray *latArray = [locationDict valueForKey: #"lat"]; NSString *latString = [latArray lastObject]; // (one element) array entries provided by the json parser
NSArray *lngArray = [locationDict valueForKey: #"lng"]; NSString *lngString = [lngArray lastObject]; // (one element) array entries provided by the json parser
myLocation.latitude = [latString doubleValue]; // the json parser uses NSArrays which don't support "doubleValue"
myLocation.longitude = [lngString doubleValue];
return myLocation;
}

Answer 4

Update version, using iOS JSON:
- (CLLocationCoordinate2D)getLocation:(NSString *)address {
CLLocationCoordinate2D center;
NSString *esc_addr = [address stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *req = [NSString stringWithFormat:#"http://maps.google.com/maps/api/geocode/json?sensor=false&address=%#", esc_addr];
NSData *responseData = [[NSData alloc] initWithContentsOfURL:
[NSURL URLWithString:req]]; NSError *error;
NSMutableDictionary *responseDictionary = [NSJSONSerialization
JSONObjectWithData:responseData
options:nil
error:&error];
if( error )
{
NSLog(#"%#", [error localizedDescription]);
center.latitude = 0;
center.longitude = 0;
return center;
}
else {
NSArray *results = (NSArray *) responseDictionary[#"results"];
NSDictionary *firstItem = (NSDictionary *) [results objectAtIndex:0];
NSDictionary *geometry = (NSDictionary *) [firstItem objectForKey:#"geometry"];
NSDictionary *location = (NSDictionary *) [geometry objectForKey:#"location"];
NSNumber *lat = (NSNumber *) [location objectForKey:#"lat"];
NSNumber *lng = (NSNumber *) [location objectForKey:#"lng"];
center.latitude = [lat doubleValue];
center.longitude = [lng doubleValue];
return center;
}
}

Answer 5

The following method does what you asked for. You need to insert your Google maps key for this to work correctly.
- (CLLocationCoordinate2D) geoCodeUsingAddress:(NSString *)address{
int code = -1;
int accuracy = -1;
float latitude = 0.0f;
float longitude = 0.0f;
CLLocationCoordinate2D center;
// setup maps api key
NSString * MAPS_API_KEY = #"YOUR GOOGLE MAPS KEY HERE";
NSString *escaped_address = [address stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding];
// Contact Google and make a geocoding request
NSString *requestString = [NSString stringWithFormat:#"http://maps.google.com/maps/geo?q=%#&output=csv&oe=utf8&key=%#&sensor=false&gl=it", escaped_address, MAPS_API_KEY];
NSURL *url = [NSURL URLWithString:requestString];
NSString *result = [NSString stringWithContentsOfURL: url encoding: NSUTF8StringEncoding error:NULL];
if(result){
// we got a result from the server, now parse it
NSScanner *scanner = [NSScanner scannerWithString:result];
[scanner scanInt:&code];
if(code == 200){
// everything went off smoothly
[scanner scanString:#"," intoString:nil];
[scanner scanInt:&accuracy];
//NSLog(#"Accuracy: %d", accuracy);
[scanner scanString:#"," intoString:nil];
[scanner scanFloat:&latitude];
[scanner scanString:#"," intoString:nil];
[scanner scanFloat:&longitude];
center.latitude = latitude;
center.longitude = longitude;
return center;
}
else{
// the server answer was not the one we expected
UIAlertView *alert = [[[UIAlertView alloc]
initWithTitle: #"Warning"
message:#"Connection to Google Maps failed"
delegate:nil
cancelButtonTitle:nil
otherButtonTitles:#"OK", nil] autorelease];
[alert show];
center.latitude = 0.0f;
center.longitude = 0.0f;
return center;
}
}
else{
// no result back from the server
UIAlertView *alert = [[[UIAlertView alloc]
initWithTitle: #"Warning"
message:#"Connection to Google Maps failed"
delegate:nil
cancelButtonTitle:nil
otherButtonTitles:#"OK", nil] autorelease];
[alert show];
center.latitude = 0.0f;
center.longitude = 0.0f;
return center;
}
}
center.latitude = 0.0f;
center.longitude = 0.0f;
return center;
}

Answer 6

For the google map key solution, as described by unforgiven above, doesn't one has to make the app free? As per google terms & conditions: 9.1 Free, Public Accessibility to Your Maps API Implementation. Your Maps API Implementation must be generally accessible to users without charge.
With map kit in sdk 3.0 this is easily done using the SDK. See apple's manuals or follow: https://developer.apple.com/documentation/mapkit

Answer 7

There's also CoreGeoLocation, which wraps up the functionality in a framework (Mac) or static library (iPhone). Supports lookups through Google or Yahoo, if you have a preference for one over the other.
https://github.com/thekarladam/CoreGeoLocation

Answer 8

- (void)viewDidLoad
{
app=(AppDelegate *)[[UIApplication sharedApplication] delegate];
NSLog(#"%#", app.str_address);
NSLog(#"internet connect");
NSString *Str_address=_txt_zipcode.text;
double latitude1 = 0, longitude1 = 0;
NSString *esc_addr = [ Str_address stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *req = [NSString stringWithFormat:#"http://maps.google.com/maps/api/geocode/json?sensor=false&address=%#", esc_addr];
NSString *result = [NSString stringWithContentsOfURL:[NSURL URLWithString:req] encoding:NSUTF8StringEncoding error:NULL];
if (result)
{
NSScanner *scanner = [NSScanner scannerWithString:result];
if ([scanner scanUpToString:#"\"lat\" :" intoString:nil] && [scanner scanString:#"\"lat\" :" intoString:nil])
{
[scanner scanDouble:&latitude1];
if ([scanner scanUpToString:#"\"lng\" :" intoString:nil] && [scanner scanString:#"\"lng\" :" intoString:nil])
{
[scanner scanDouble:&longitude1];
}
}
}
//in #.hfile
// CLLocationCoordinate2D lat;
// CLLocationCoordinate2D lon;
// float address_latitude;
// float address_longitude;
lat.latitude=latitude1;
lon.longitude=longitude1;
address_latitude=lat.latitude;
address_longitude=lon.longitude;
}

Answer 9

func geoCodeUsingAddress(address: NSString) -> CLLocationCoordinate2D {
var latitude: Double = 0
var longitude: Double = 0
let addressstr : NSString = "http://maps.google.com/maps/api/geocode/json?sensor=false&address=\(address)" as NSString
let urlStr = addressstr.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)
let searchURL: NSURL = NSURL(string: urlStr! as String)!
do {
let newdata = try Data(contentsOf: searchURL as URL)
if let responseDictionary = try JSONSerialization.jsonObject(with: newdata, options: []) as? NSDictionary {
print(responseDictionary)
let array = responseDictionary.object(forKey: "results") as! NSArray
let dic = array[0] as! NSDictionary
let locationDic = (dic.object(forKey: "geometry") as! NSDictionary).object(forKey: "location") as! NSDictionary
latitude = locationDic.object(forKey: "lat") as! Double
longitude = locationDic.object(forKey: "lng") as! Double
}} catch {
}
var center = CLLocationCoordinate2D()
center.latitude = latitude
center.longitude = longitude
return center
}