[Talk-ca] Address ranges

Richard Weait richard at weait.com
Tue Mar 24 01:24:44 GMT 2009

On Mon, 2009-03-23 at 19:55 -0400, Bob Jonkman wrote:
> On 22 Mar 2009 at 12:02 Steve Singer <ssinger_pg at sympatico.ca> wrote
> about "Re: [Talk-ca] Address ranges[...]"
> >Part of me prefers a scheme that adds address tags directly to the nodes
> >that make up the road.
> >
> >The downside of that is[...]
> Another downside is that it doesn't reflect reality (or, rather, it 
> reflects reality even less than an arbitrary offset).
> I'd rather see generated nodes (as per Richard Weait's suggestion) 
> with additional "addr" tags, eg.
> building=yes
> addr:housenumber=123
> addr:type=generated-blockface
> addr:offsetlat=0.00003
> addr:offsetlon=-0.00001
> addr:offsetnodeid=<nodeid>
> This would be an indication that it's a suitable candidate for 
> replacement with observed data.  If the associated road node is moved, 
> the building node doesn't necessarily have to be moved, but could be 
> re-calculated (which opens its own can of worms).

Are you combining two address data issues?  

For block face addressing, we need to interpolate building location.
That was when the arbitrary offset was suggested.  I believe we have _in
other locations_ building point locations.  Are there addresses
associated with those building points?  If so, no interpolation

Also, Karlsruhe schema explicitly allows addr:housenumber as a node OR
polygon.  So no need to fake the polygons to comply with the schema.  I
believe that the sample image shows two point-buildings "6" and "4" on
the north side of Bochumer Straße?   

> One problem is that not all addresses are necessarily buildings.  
> Sometimes a park, public square or empty lot has an address.  And all 
> buildings aren't necessarily houses, so I'm not sure that 
> "housenumber" is the most appropriate tag name.

But it is what we have for the schema.  The discussion suggests that we
can make suggestions.

> When I worked at the City of Toronto and had access to their Central 
> Property Register database there were different concepts of municipal 
> addresses, postal delivery addresses, and courtesy addresses.  I 
> expect that GeoBase captures the municipal addresses. 

Which is the one that is easiest to detect when walking past the
building?  Municipal?  

> Also, I'm in favour of generating a small polygon (square) rather than 
> a single node.  This fixes Michel Gilbert's rendering problem, and 
> also more closely reflects reality.

I respectfully disagree.  And I hope that adding addr:housenumber will
work as per my guess above.  

Some have said that we shouldn't tag for the renderer.  And then others
have said that and still done amazing work by tagging for the renderer.

Adding a fake polygon may also subtly discourage mappers from going and
mapping the buildings.  "Look at those cute, even, rectangular
buildings.  Obviously I don't need to fix that with aerial images..."  

Kind of like hacking css for a month to make it work with IE5.  Wasted
effort; bad for the psyche.  Design for the standard and you are certain
to work with the browsers of the future (renderers of the future).  

My thoughts, while my tiles render.  ;-)

Best regards,

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