[Talk-us] San Diego Address Import Update

Tod Fitch tod at fitchdesign.com
Tue Nov 10 15:48:20 UTC 2015

> On Nov 10, 2015, at 5:59 AM, Greg Troxel <gdt at ir.bbn.com> wrote:
> Tod Fitch <tod at fitchdesign.com> writes:
>> What is a “city” in US specific OSM terms?
>> I prefer a postal city definition as that is the most useful for
>> routing purposes which I feel is the primary use of address data in
>> OSM. Or are we dealing with some other concept of addr:city?
> I see it as fairly clear that addr:city is about administrative
> boundaries and what the local civil government considers to be legal
> physical addresses (vs mailing addresses).
> In Massachusetts this is very clear; every bit of land is in a city or
> town, and there are (mostly) granite markers at the corners.
> In states with unincorporated areas, it seems like there are areas with
> cities, and then areas beyond the city where some rules apply, and then
> areas that are in a county but not really in a city, so I can see that
> this is complicated.
> It would be interesting to ask the assessors or the police/fire
> department or PSAP operators how they see addresses and cities in these
> areas.
> I would suggest that if we want to tag postal addresses vs legal
> addresses that those have tags that are explicitly about postal.

This is getting away from San Diego address import updates, but I think this is a topic that needs to be clarified. What is a city for the purposes of addr:city tag values in the US in the OSM database?

For what it is worth, in California (at least in the counties I have lived in) the legal description of a piece of land is a designation of the map book, page and parcel number in the county records. I believe the street name and number as well as the city name and ZIP code on the parcel can change over time and it does not change the legal description. So if addr:street, addr:housenumber, addr:city, etc. are not set to the legal description what should they be set to?

Here are some places that I am pretty familiar with having either lived in them or with extended visits to family who live in them.

First, Tucson, AZ. Tucson is an incorporated city with legally defined boundaries. When I lived there (many years ago) we didn’t actually live within the city limits but in a residential subdivision between the city and the mountains to the north. The “city” used in the address for all those years was always “Tucson” even though we were never within the incorporated city limits and civil administration was through the county. There were no other incorporated cities or towns near by, so if Tucson was not an option for city name then the only logical choice would be an empty or blank. Nobody ever left the city portion of an address field blank when filling out forms, “Tucson” was always used but it fails the administrative boundary test.

Second, Oracle, AZ. This town has existed for over 100 years but is not incorporated and, near as I can tell, has no official boundaries. There is a CDP for it but the boundaries on that do not seem to match what the locals consider the town. It has a volunteer run library, a volunteer fire department, a post office, a county administration office including court facilities and a sheriff’s substation. All with “Oracle” in their names and when you call 911, the PSAP wants to know that you are “in” Oracle (no enhanced 911 in the area yet). So it passes the “duck test” for a town. But it has no administrative boundaries and no concrete or granite boundaries at the corners and civil administration is handled from the county seat (about an hour drive away) so it fails the formal administrative boundary test. What value should be used for addr:city tags in that area? “Oracle” seems correct to me.

Third, Sunnyvale, CA. seems to more closely match the Massachusetts model as the area is pretty well built up and has relatively clear boundaries with adjacent incorporated cities (Mountain View, Los Altos, Cupertino, Santa Clara). But it turns out that there are small parcels of land surrounded by the city which are not legally part of it and are under county jurisdiction. I don’t really know how fire and police response to those parcels work, I suspect the county has an agreement with the city to have the city respond but I don’t really know. Walking or driving by them you will not see any visible indication that the land is not part of the city. It is only when a builder decides to put something big on it do you find out that the land isn’t officially in the city and the permit and planning have to be approved by the county (almost always with city input as an interested party). So what OSM city name should be used on those parcels (assuming you can identify them on the ground)? “Sunnyvale” seems like the right answer to me but it would fail the administrative boundary test.

Finally, Los Angeles. The incorporated area for LA is huge and it surrounds other incorporated cities. But there are areas in LA like Woodland Hills, Chatsworth, Canoga Park, Van Nuys, and Studio City where the locals, when asked, won’t say they are in LA. They will give the local area name even though they are part of the city of Los Angeles. The postal address is also the local name. And the city of LA has even posted signs, similar to those you see when entering an incorporated city or town, indicating you are entering those locally named places. What should the addr:city name be?

So what is a good definition for what should go in the addr:city tag? If it is based on being within a formal administrative boundary then we may not need the tag at all as it should be easy for a data consumer to detect that. I have come to the conclusion that the addr:city is best to indicate what the locals feel their town name is. In the western US my impression is that has a high correlation with the USPS designation. Further, when dealing with any financial or government entity, it seems the city they want to hear about is the one the post office delivers to, not some subset or superset defined by a formal boundary of an incorporated town or city. So equating the post office town name with the OSM addr:city value seems proper to me.

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