[OSM-dev] How to tag addresses
shaunmcdonald131 at gmail.com
Thu Jun 14 12:04:25 BST 2007
On 14 Jun 2007, at 11:40, Robert (Jamie) Munro wrote:
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> Dave Hansen wrote:
>> On Wed, 2007-06-13 at 16:14 -0700, Brandon Martin-Anderson wrote:
>>> The problem with address geocoding is like this: there is absolutely
>>> no national standard for street addressing, let alone international
>>> standard. Any and every assumption you make about the way addresses
>>> should work can be and is violated all the time. Street addresses
>>> even be out of order, even in some places in the US. The only way to
>>> use a single dataset for address geocoding on a national scale is
>>> brute force - for every little segment one or more address ranges is
>>> specificed for both the right and lefthand side of the street (with
>>> respect to the direction the line is traveling, even when the
>>> line is
>>> a two-way street).
>> Sounds sensible. I do worry what happens if, for instance, a segment
>> has its direction changed. This is pretty common when people are
>> merging ways together. Whatever was doing the merging would need to
>> have the knowledge to flip around those address tags.
>> Would it be more sensible to make these cardinal-direction-based,
>> instead of left/right? Addresses for the north and south sides of
>> street? If the street was perfectly north/south, you could pick
>> east or west to be the surrogate north.
> I've previously suggested that you use north/south if the road is
> 45 degrees of horizontal, and east/west if it's within 45 degrees of
> vertical. If it's bang on 45 degrees, or even just close, you can use
> either. This way it won't go wrong if someone moves a node slightly.
You would need to allow for circular roads like the M25 around
London. Thus the addition of clockwise and anti-clockwise.
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