Re: [Talk-us] Address Node Import for San Francisco

2010-12-10 Thread Alan Mintz

At 2010-12-09 17:14, Katie Filbert wrote:

...
With buildings, our data was a bit denser. I did some by census tract and 
found some were too big for the OSM API and JOSM whereas census block 
group has worked well. With just nodes, I think you could do somewhat 
larger chunks.


Were the shapes (needlessly) over-digitized? I saw this with some of the 
CASIL polygons, and with much of Kern County, where huge reductions 
(thousands of nodes per square mile) were possible with little effect on 
rendering, using the JOSM "simplify". Hopefully there is something similar 
available in the import tool collection.


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Re: [Talk-us] Address Node Import for San Francisco

2010-12-10 Thread Alan Mintz

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.


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Re: [Talk-us] Address Node Import for San Francisco

2010-12-10 Thread Katie Filbert
On Dec 10, 2010, at 5:10 AM, Alan Mintz   
wrote:



At 2010-12-09 17:14, Katie Filbert wrote:

...
With buildings, our data was a bit denser. I did some by census  
tract and found some were too big for the OSM API and JOSM whereas  
census block group has worked well. With just nodes, I think you  
could do somewhat larger chunks.


Were the shapes (needlessly) over-digitized? I saw this with some of  
the CASIL polygons, and with much of Kern County, where huge  
reductions (thousands of nodes per square mile) were possible with  
little effect on rendering, using the JOSM "simplify". Hopefully  
there is something similar available in the import tool collection.


Yes, simplifying the buildings in JOSM is an important step in the  
process.   I tweaked the simplify param to get it best as possible.   
Though not 100% happy with the results so do some more manual tweaking  
in JOSM


Katie





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