iOS Find Location (Latitude,longitude) from Zipcode - iphone

Question

What could be the best way to get location for a given zipcode. Would it work for countries outside US/Canada .Thanks

Answer 1

Use the Google geolocating API (try it out on google.com/maps):
Input for a Swiss ZIP code for example:
CH-9014
or a french one:
FR-34000
or german:
de-12101
or US:
us-90210
or canada:
ca-J5Z 1A1
or china:
cn-100000
for example:
yields
{
"status": "OK",
"results": [ {
"types": [ "postal_code" ],
"formatted_address": "9014 St Gallen, Switzerland",
"address_components": [ {
"long_name": "9014",
"short_name": "9014",
"types": [ "postal_code" ]
}, {
"long_name": "St Gallen",
"short_name": "St Gallen",
"types": [ "locality", "political" ]
}, {
"long_name": "Sankt Gallen",
"short_name": "SG",
"types": [ "administrative_area_level_1", "political" ]
}, {
"long_name": "Switzerland",
"short_name": "CH",
"types": [ "country", "political" ]
} ],
"geometry": {
"location": {
"lat": 47.4082855,
"lng": 9.3323890
},
"location_type": "APPROXIMATE",
"viewport": {
"southwest": {
"lat": 47.3991076,
"lng": 9.3180504
},
"northeast": {
"lat": 47.4199564,
"lng": 9.3543340
}
},
"bounds": {
"southwest": {
"lat": 47.3991076,
"lng": 9.3180504
},
"northeast": {
"lat": 47.4199564,
"lng": 9.3543340
}
}
}
} ]
}
So the swiss ZIP code 9014 corresponds appx. to this location:
"lat": 47.4082855,
"lng": 9.3323890
See my answer on the geolocating API here:
How to get GLatLng object from address string in advance in google maps?

Answer 2

GeoNames offers a number of various zipcode geocoding services, including search for the location of a given zipcode. They support a number of various countries.
You would probably be most interested in the Placename Lookup for postalcode service

Answer 3

Google's API comes with some fairly nasty restrictions. Better to use open sources like GeoNames per #Claus Broch's suggestion.
I'm adding this answer to also note that MapQuest has recently put up an API to OpenStreetMap data. It doesn't do (as far as I can tell) zip code searching, but location names, directions, altitude etc are all freely queryable. I recently discovered it an I plan on replacing my calls to google maps API with it as soon as I can.
http://developer.mapquest.com/web/products/open