I am using Google's reverse geocoding functionality with the maps api v3 to retrieve postal addresses for latitude longitude (when dragging a marker around a map).
This is a UK application only, and part of the system requires a full, or near full, postcode to process correctly. However the reverse geocoder regularly returns just the part of the postcode - for example "GU3", even when the actual address returned appears to be complete - for example including street and house number.
Is there anyway, preferably google but otherwise if not, of 'snapping' the address to the nearest full postcode?
I'm aware similar functionality exists for snapping to the nearest panorama view, but there appears to be no equivalent for postcode.
The UK post code database is available for download from the Ordnance Survey open data www.ordnancesurvey.co.uk/opendata
Alternatively you can use a service like uk-postcode.com to return the closest post codes to a location
See the example at https://google-developers.appspot.com/maps/documentation/javascript/examples/geocoding-reverse
Try a UK location like 51.436951, 0.058112.
The results include an address_component of postal_code, "SE9 3AG".
It may be necessary to geocode the address you're given and then reverse-geocode the results in order to get the postcode. But it is possible.
来源：https://stackoverflow.com/questions/9689692/google-reverse-geocoding-how-to-snap-to-nearest-full-postcode