[Tagging] Housenumber interpolation with regularlyskippednumbers

Mike N. 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
> apartments/condos).

   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 
>> on
>> 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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