[Talk-us] Address Node Import for San Francisco

Alan Mintz Alan_Mintz+OSM at Earthlink.Net
Fri Dec 10 10:28:00 GMT 2010

At 2010-12-09 15:00, Gregory Arenius wrote:
>About the data.  Its in a shapefile format containing about 230,000 
>individual nodes.  The data is really high quality and all of the 
>addresses I have checked are correct.  It has pretty complete coverage of 
>the entire city.

Do spot-check different neighborhoods. In reviewing the San Bernardino 
County assessor's shapefile, I found that housenumbers, ZIP codes, and even 
street names were missing/wrong in some areas I spot-checked. The county's 
response was that this data was of secondary importance to the assessor, 
understandably - as long as they have all the parcels, and the billing 
address for them, the actual postal address of the parcel is not critical info.

>First, I've looked at how address nodes have been input manually.  In some 
>places they are just addr:housenumber and addr:street and nothing 
>else.  In other places they include the city and the country and sometimes 
>another administrative level such as state.  Since the last three pieces 
>of information can be fairly easily derived I was thinking of just doing 
>the house number and the street.
>  The dataset is fairly large so I don't want to include any extra fields 
> if I don't have to.  Is this level of information sufficient?  Or should 
> I include the city and the state and the country in each node?

I don't agree that the other info can be easily, or accurately, derived. 
Addresses near the borders of those polygons are often subject to 
seemingly-arbitrary decisions. The physical location of the centroid of a 
parcel may not be within the same ZIP, city, and/or county polygons as 
their address. I would include the city and ZIP code.

Note, BTW, that there are lots of ZIP code issues that come up, and I'm not 
always sure how to deal with them. I'll look up an address I know to exist 
using http://zip4.usps.com/zip4/welcome.jsp, but it won't find it - often 
because the USPS uses a different city name. It seems to happen a lot in 
rural areas, but not exclusively, and not always for the reason you might 
think (that it's the city of the post office that serves the address). 
Hopefully, that won't be a problem for your single-city import, though.

Alan Mintz <Alan_Mintz+OSM at Earthlink.net>

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