In the United States, "ZIP" codes (postal codes) make some existing lookup functionality difficult to use, especially for practices in larger cities. Large cities, such as New York, Chicago, Los Angeles and others may have up to 200 unique zip codes associated with the city. Even cities with 10 or so zip codes are difficult to look up. The existing XML postcodes.xml load file, modified with US states, cities and zip codes does work - however each city with multiple zip codes is listed multiple times, and there is no indication which rendition of the city is tied to which zip code. I can provide an example XML load file to test with to illustrate the problem.
One solution would be to have the post code tied to the city through a lookupRelationship, so when a city is selected, a list box of valid zip codes for that city is presented. Alternatively, if a zip code is typed into the postcode box then the city and state are uniquely identified and could be popluated in that manner.
software platform, archetypes.