[uf-discuss] Geo precision

[Ben O'Neill]

>> On 8/27/07, Ben Ward <lists at ben-ward.co.uk> wrote:
>>> Since then the only additional information I've found is that Flickr
>>> stores accuracy (as an integer) based on the zoom level of the map
>>> when you place a photo. In fact, if you zoom all the way out and
>>> place a photo you'll get a notice warning you that the location is
>>> too approximate and the photograph won't show up at higher zoom  
>>> levels.
>>
>> I've been doing some work with Google's geocoder, encoding addresses
>> into co-ordinates for mapping purposes.
>>
>> Google uses an 9-point enum that is specified as a
>> human-understandable scale rather than specific geographical terms:
>>
>> 0	 Unknown location.
>> 1	 Country level accuracy.
>> 2	 Region (state, province, prefecture, etc.) level accuracy.
>> 3	 Sub-region (county, municipality, etc.) level accuracy.
>> 4	 Town (city, village) level accuracy.
>> 5	 Post code (zip code) level accuracy.
>> 6	 Street level accuracy.
>> 7	 Intersection level accuracy.
>> 8	 Address level accuracy.

Flickr uses a 16 point system:

- World level is 1
- Country is ~3
- Region is ~6
- City is ~11
- Street is ~16

This is taken from the Flickr API <http://www.flickr.com/services/api/ 
flickr.photos.search.html>