Talk:Key:postal code

Different postal codes in one street

I've read on the official site of our postal provider, that it's possible that 2 postal codes can occur on the same road. The distinction would be in the difference of the street number. Can this happen in other countries? source: http://english.elta.gr/index.asp , FAQ on postal codes Logictheo 09:55, 15 September 2008 (UTC)

Yes, just split the way where the postal code changes. If the codes are different on opposite sides of the road, there's no definitive solution, yet; the Karlsruhe schema can be used to mark the individual addresses with their correct postal codes. Alv 12:58, 28 October 2008 (UTC)

Actually in the UK a building can have two different postal codes if it's tall enough! (ie has enough separate addresses in it). I lived in one such building, in Leeds, which is 30 stories tall - we had LS11 5QB for half of the building, and LS11 5QT for the other half. I'm guessing it was T for top and B for bottom but I'm not sure. I think there's a rule regarding the maximum number of houses (etc) allowed at the lowest level of granuality (the 'postcode unit') but I can't find a reference for this so I might be wrong. Justinep 16:20, 31 October 2009 (UTC)

UK: Newbie: If I look in my address book, I can put postcodes to a couple of hundred existing streets, even though many I have not visited. I may even have 2 postcodes for a single street, but I don't know where the break is (unless I were to illegally copy from the post office). In this case, should I put 2 postal_code tags against the track for now, then if someone can elaborate, they can either split it or use the Karlsruhe scheme to clarify. What are your thoughts? --Finiteresource 20:53, 30 June 2010 (UTC)

Use the FIXME tag. Lulu-Ann

In Berlin, Germany there are some streets, that have one postcode on one side of the street, and another on the other side of the street. So what would I do to the streets tag postal_code? Remove it? Or rename it to 10999/10997 or something (this example was for eastern part of the Oranienstraße). Wicking (talk) 05:05, 28 February 2013 (UTC)

postal_code:forward=10999

postal_code:backward=10997

See Forward & backward, left & right --Tony Rotondas (talk) 11:23, 4 April 2014 (UTC)

Postal codes in the United States

Would it be appropriate to include the United States in the table of formats? Or are the US ZIP codes dealt with elsewhere? P.S. I am aware of the treatment at Search#US ZIP Codes, but the Geocoder.us system does not appear to deal with the +4 extension (ZIP+4). --Ceyockey 01:28, 16 August 2009 (UTC)

Tasks

Offer a service, that lists the average distance between two postal codes.

How to gather data?

The article expressly states that postcode information should not be copied from "other sources" but it doesn't explain what other alternatives that leaves. Postal codes in the UK aren't printed on street signs (which would constitute a "other source" even if they were). What alternative does that leave? Knocking on every single door and asking people for their postcode? It seems we're being asked to pull the information from thin air otherwise.

The comparison is made with geo data but that's very different, I can see geo data with my own eyes in the field, postcodes are arbitrarily assigned designations which are not displayed on or near the property itself. --GBee 10:00, 30 April 2011 (BST)

I've added a bunch more detail there.

If you're in the UK though Free The Postcode#UK summarises the situation now. OS Opendata#Code-Point Open rather changes things although it doesn't make collecting key:post_code values completely irrelevant

-- Harry Wood 13:01, 2 May 2011 (BST)

Personally I'd rather attach postcode data to individual buildings (addr:postcode) when possible, which Free The Postcode and Code-Point don't help with. They both attempt to place a node at the rough centre of the postcode area but don't define the boundaries or which properties the postcode applies to. I guess that just leaves me the option of knocking on every single door in the city.--GBee 17:38, 12 May 2011 (BST)

In the United States, a broad, freely available solution to this problem (at LEAST as a first pass, and certainly useful to Nominatim) would be ZCTAs, Zip Code Tabulation Areas, as determined by the U.S. Census. These are available at TIGER/Line® Shapefiles and TIGER/Line® Files, with the 2014 edition released on August 19, 2014. Thsee shapefiles would likely want to be stitched together into shared boundary relations -- as has generally been done in Germany and Belgium on boundary=postal_code relations. ZCTAs are fully explained at ZIP Code™ Tabulation Areas (ZCTAs™). For individual or small clusters of addresses that do not appear in the ZCTAs, they need to be individually specified on address nodes. Skybunny (talk) 06:50, 29 September 2014 (UTC)