[Talk-us] [Imports] [Talk-ca] TIGER considered harmful

Anthony osm at inbox.org
Mon Nov 16 00:52:45 GMT 2009


On Sun, Nov 15, 2009 at 7:24 PM, Peter Batty <peter.batty at gmail.com> wrote:
> I'm coming a bit late to this debate, but I just wanted to raise a fairly
> basic question, which is whether the Karlsruhe schema is the best one to use
> in the situation we find ourselves in with TIGER, where quite a bit of data
> cleanup is anticipated.

I signed up for the "USA 'conversion team'" with the express intention
of challenging the use of the Karlsruhe schema.  Maybe you can sign up
too (even if you're not in the US).

> The main challenge with
> maintaining this format, as Frederik and others pointed out, is if you split
> or join a way. But it's relatively easy to put logic in editors to handle
> that, and even if you have to do it manually, it seems to me easier to
> maintain this model than the more precise Karlsruhe schema if you are doing
> quite a bit of data cleanup.

The TIGER data has already been significantly degraded from people
doing just this type of thing.  The problem is, if a way goes from 2
to 100, and you want to split it in the middle (say, due to a change
in the number of lanes), you have to either resurvey the addresses or
take a shot in the dark and split it 2-48, 50-100.  That might be
reasonable if the 2-100 were accurate in the first place, but if that
2-100 were really 2-20, you've seriously screwed things up.  The TIGER
data already contains large numbers of instances of exactly this, but
there's no sense introducing a schema which makes this even worse.

On the other hand, there are other possibilities which avoid this
problem and also avoid creating multiple ways.  Join the conversion
team with me and we can talk about them.

> So this is not an either / or proposal of course - both forms could exist,
> and you search for the more precise form before the more approximate form.

As much as I hate the meme of saying +1 when you agree with someone, I
have to say +1.  Or maybe "AMEN".

On Sun, Nov 15, 2009 at 7:47 PM, Dale Puch <dale.puch at gmail.com> wrote:
> I personally favor having the possible address range in the street way
> segment (between intersections)

Join the team!

Anthony




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