Subject: RE: [Ecrit] Proposed requirement: split responsibility

From: "Abbott, Nadine B" <[email-masked]>
Date: Tue, 24 May 2005 09:59:18 -0400

Brian,

Actually, there are some metro areas even in the USA where the hierarchy
you suggested breaks down (i.e., multiple counties in NYC), but I think
it could still be modeled with multiple instances of NYC, one for each
county.

(As an aside, I think that a hierarchy may be one way to implement the
mapping data base, but building a hierarchy in the query protocol is, I
think, a bad idea.  What if you guess wrong?  Hard to fix, later.)

Nadine

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Brian Rosen
Sent: Tuesday, May 24, 2005 9:36 AM
To: 'Andrew Newton'
Cc: [email-masked]
Subject: RE: [Ecrit] Proposed requirement: split responsibility

Yes, I thing we are agreeing that at the street level, which includes
street name, pre and post directionals, and suffix, there is no
hierarchy.

Similarly, there is no hierarchy for House Number and the House Number
Suffix, the Landmark Name, etc.

The only point in a hierarchy above that is to create some feasible
mechanism to distribute the database.  There are reasons to want to do
that, and hierarchy makes sense at the city/county/state/country level.

Brian

> -----Original Message-----
> From: Andrew Newton [mailto:[email-masked]]
> Sent: Tuesday, May 24, 2005 9:25 AM
> To: Brian Rosen
> Cc: [email-masked]; 'Ted Hardie'; 'Henning Schulzrinne'
> Subject: Re: [Ecrit] Proposed requirement: split responsibility
> 
> 
> On May 24, 2005, at 8:51 AM, Brian Rosen wrote:
> 
> > So, South Main Street may route differently than South Main Avenue, 
> > but we don't have anything that says all Streets route differently 
> > that all Avenues, and we don't have anything that says all "South"
> > predirectionals
> > route differently than all "North" predirectionals.
> 
> I think, you are saying there is no hierarchy... at least at the 
> street level.  I am arguing that there should not be a hierarchy.  Let

> me refine that, no hierarchy should be imposed.  Certainly there are 
> many jurisdictions that have a hierarchy related to civic address 
> fields, but I do not think they are the same hierarchy the world 
> around.
> 
> -andy
> 
> 

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---

From: "Brian Rosen" <[email-masked]>
Date: Tue, 24 May 2005 10:36:17 -0400

Nadine

Generally, I agree with you that hierarchy at the city level occasionally
has problems, and I also agree there are straightforward work arounds for
those problems.  It's often the case that a PSAP serves more than one point
in any hierarchy.  An easy example is that often, a County PSAP serves all
of a county except a large city.  You can accomplish that by having entries
for all of the cities, or you can "delegate" the county to one entity, and
have it "delegate" the city to another.  Your New York City example is
similar.

You need some rational way to split up the database.  Doing it on
City/County/State/Country boundaries is a good start, but insufficient, as
you know.  Your choices, when say, a part of a street are in a different
PSAP from all the other streets in a city, are:
	1. Allow the database to be split on arbitrary boundaries and have 
		some mechanism such as referral, or delegation to route a 
		query to the right server
	2. Split the database on a city/county/state/country boundary
		and force the data to match this split
 	3. Duplicate coverage on city/county/state/country boundaries
		i.e. have more than one potential server, and search them in

		parallel or series.

The thing about addresses is that they are very old, and we don't often
change the way we address.  We did add postal codes a while ago, but it's
not like anything on the Internet.  There is some danger that we don't
adequately investigate existing practice, in some area of the world and
subsequently discover some issues.

Brian

> From: Abbott, Nadine B [mailto:[email-masked]]
> Sent: Tuesday, May 24, 2005 9:59 AM
> To: Brian Rosen; Andrew Newton
> Cc: [email-masked]