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I am totally new to Geocoding on the iPhone, or any other platforms, and I would like to know. Is a default iPhone MapKit a forward or reverse geocoding? And what is forward and reverse mean?

Is there a documentation in the iPhone that explains both? Some examples would be nice too :)

Thanks guys!

Melvin Lai
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5 Answers5

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Forward - Human readable address to coordinates.

Reverse - Coordinates to readable address.

Do check out SVGeocder. It supports both forward and reverse geocoding via Google API.

The iOS SDK has a MKReverseGeocoder class to support reverse geocoding but I don't find it very accurate.

Gavin
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Geocoding is taking an address (or similar) and translating it into lat/long coordinates.

Reverse GeoCoding is taking a set of coordinates and translating them into an address.

Jason
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  • so by default, iPhone uses a Geocoding? The default Map application that comes with the phone. – Melvin Lai Aug 17 '11 at 04:01
  • iOS provides functions to do both. But plotting an address on a map is by definition geocoding. – Jason Aug 17 '11 at 04:09
  • as @benwong points out, there is actually not a built in function for geocoding. But there is a wrapper for Google's reverse geocoding service included in the API. – Jason Aug 17 '11 at 04:16
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Geo-coding is like if you have an address and you want to get the latitude and longitude of that address.

and reverse Geo-coding is that if you have latitude and longitude and you want to find city or country code or area from which this latitude and longitudes are.

Kavita Mevada
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A geocoder object uses a network service to convert between latitude and longitude values and a user-friendly placemark, which is a collection of data such as the street, city, state, and country information.

  • Reverse geocoding is the process of converting a latitude and longitude into a placemark.
  • Forward geocoding is the process of converting place name information into a latitude and longitude value.

Reverse geocoding is supported in all versions of iOS but forward geocoding is supported only in iOS 5.0 and later.

Nikana Reklawyks
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user11
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You can read about Geocoding in Apple's Location Awareness Programming guide. http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/LocationAwarenessPG/UsingGeocoders/UsingGeocoders.html#//apple_ref/doc/uid/TP40009497-CH4-SW5

iOS supports reverse geocoding, but not forward geocoding. You can implement forward geocoding yourself. How do I do geocoding (NOT reverse geocoding) on iPhone?

Community
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benwong
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  • I came across this while reading the Guide. "Many geocoding services allow you to perform conversions in either direction but iOS currently supports only reverse geocoding, which converts a latitude and longitude into a placemark." I thought iPhone can do both? Or is it because this could be an old API? – Melvin Lai Aug 17 '11 at 04:32
  • "iOS supports reverse geocoding, but not forward geocoding." The Maps app on the iPhone does both forward and reverse, but Apple do not provide access to forward geocoding in their API. They never provided access to forward geocoding. – benwong Aug 17 '11 at 08:11