[Tagging] Housenumber interpolation with regularlyskippednumbers
niceman at att.net
Tue Oct 13 17:31:55 BST 2009
>> TIGER obfuscates the data by declaring the entire numbering range of a
>> zone: for example a "400 block / Even" containing houses 404 through 420
>> would be declared as "range Even / 400-498" in TIGER. For navigation
>> purposes, that gets you to within one block of an address.
> Maybe they do it for obfuscation, but that has the additional
> advantage of being able to locate an approximate address when house
> #422 (or #402) gets added to the block. Of course, we don't have to
> be quite as dumb as Tiger. We could always use three blocks,
> 400-404/Even, 404-420/Even, and 420-498/Even.
Why use 3 blocks? If a cursory survey shows that 404 and 420 are
physically the endpoints of a block, why not use a single way? Even if 420
is not the physical endpoint, why not a single way?
> It's not quite the same idea, though. The Karlsruhe Schema maps
> actual addresses, at the house location. The Tiger Schema (for lack
> of a better name) maps potential address ranges, at the street
> location. They both have their uses: If a house is located far away
> from the actual street, you would certainly want to use something like
> the Karlsruhe Schema. If you have no idea where the house is (or is
> going to be) located other than its relation to a street, you would
> want to use the Tiger Schema. Arbitrarily sticking a way some
> distance to the right or left of a highway, in order to coax
> street-level data into a house-level schema, would be inappropriate.
What is a house number after all, if not street-level data? The house
number has no meaning to the physical building if not attached to a street.
I still perceive the Tiger Schema as a variation on the Karlsruhe Schema -
the only difference is the estimated accuracy.
> And that's just the easy case, when you're not trying to combine data
> from both schemas on the same block (I'm not sure that any of these
> have been mapped yet, but imagine a rural area with lots of houses
> near the road, some houses far off the road in flag lots with long
> driveways, and some houses both on and off the road in various stages
> of development and not yet assigned addresses; or try to combine
> actual addresses and potential addresses on a road in a retail area
> with lots of strip malls with individually addressed stores; or a road
> with lots of apartment complexes/condos with individually addressed
I would never use the Karlsruhe Schema ways to determine a house/building
location. There can be many good reasons to use address interpolation when
the building location is unknown - no aerial photographs, blurred or
obstructed aerial photos, new construction, etc.
>> Now imagine if they were asked to check
>> the address relation: "Go into edit mode, check the way the arrows point
>> your street, inspect the left / right roles to be sure that the house
>> numbering is correct".
> For clarification, the direction for the purposes of right/left would
> be determined by the start and end node, not the direction of the way.
> The way could be reversed without breaking anything (and not all the
> ways have to even go the same direction).
Now I'm confused. Unless the street is one-way, the only way to find
the start and end node is to go into edit mode. Streets can be oriented in
any direction, so left/right is often not useful for physical representation
on the map.
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