[Talk-us] [Imports] Zipcode Import

[Anthony]

On Sun, Dec 20, 2009 at 12:45 PM, Jeremy Adams <milenko at king-nerd.com>wrote:

> On Sun, Dec 20, 2009 at 12:41 PM, Anthony <osm at inbox.org> wrote:
>
>> On Sun, Dec 20, 2009 at 12:29 PM, Jeremy Adams <milenko at king-nerd.com>wrote:
>>
>>> One can easily figure out what town someone is from based on their ZIP
>>> Code.  Is this not the case everywhere?
>>>
>>
>> Certainly not.  There are lots of zip codes which represent multiple
>> towns, and lots of towns which represent multiple zip codes.
>>
>> You can usually find out an approximate geographical location from a zip
>> code (at least if it isn't an APO/FPO zip code).  But if that's all you
>> want, you're best off just representing zip codes as single points in the
>> approximate geographical center of all post boxes which receive mail to that
>> zip code.  Going in the other direction, from lat/lon to zip code (assuming
>> your lat/lon is the location of a building and/or post box), requires a much
>> more specialized database which isn't currently available as public domain.
>>
>
> But the code still represents a geographic area?
>

No, the code doesn't represent a geographic area.  You can force it into a
geographic area, by defining the area in some particular way (e.g. a
multipolygon of all buildings which receive mail addressed to that zip
code).  Of course, given that definition, some zip codes will overlap
(probably not much area-wise if you use only 5 digit zip codes), and lots of
areas will have no zip code (what's the zip code for a particular point on
the highway of I-95?).
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-us/attachments/20091220/2166956f/attachment.html>