[OSM-talk] Left and Right?

[Robin Paulson]

2008/8/27 Karl Newman <siliconfiend at gmail.com>:
> What? Of course it has relevance. The number means nothing without the
> street. Houses don't have GUIDs. It has to be associated with it's street if
> you ever want to look it up by address.

i'm not sure what a guid is, i assume it's 'globally unique
identification'? in which case, yes they do - it's the property deed
number.

and it may sound pedantic, but we should really talk about the
*property address*, not the *house address* - the first includes
driveway, paths, car parks, garden, etc, etc. and maybe does not have
a building there at all; the second makes all sorts of assumptions
which will only be true in a small number of addresses

this is going to be very relevant in the near future - land
information new zealand are more than likely going to give us
permission to include their property info database (the entire
country, probably around a million ways defining property boundaries)
in osm, so we're going to need a tagging scheme that accounts for it,
and ties together the deed number and the street address

>> numbers being part of a street but in reality they aren't, they are
>> references for buildings. The second reason is that if we were to add
>> nodes
>> for every house on both sides of the street to every way we would soon
>> find
>> out ways totally unmanageable. As a further reason, houses are normally
>> connected to the street with a driveway/footpath. In a fully featured map
>> you would draw these in eventually. Its these that make the true
>> relationship between building and street.

spot on.

> There's no need to add house numbers at every node in a way (except for
> weird cases where the house numbers are not sequential). Put the numbers at
> intervals and let interpolation take care of the rest.
>>
>> Always try top keep things simple. Keep like with like and don't try to
>> over
>> engineer the result and generally the result will be more than sufficient.
>
> The Karlsruhe schema is an example of what you get without any engineering
> at all--just look how many different scenarios are presented on that page!
> The common method used by other systems which store house numbers (for
> example, TIGER) is to associate a house number with the way and indicate if
> it's on the left or right. This is done only at certain points, and linear
> interpolation takes care of the rest. This is also what's expected by
> existing navigational systems (e.g., Garmin GPS) and if we ever hope to be
> able to use our house number data there, it needs to be able to be
> transformed into that format. The Karlsruhe schema does not allow for that
> without a huge amount of work and a lot of uncertainty about the result.
>
> I'm not opposed to putting the house number on a separate node, but it needs
> to be topologically connected with the way using a relation in that case,
> because in real life, the house address *is* associated with the street it's
> on