Re: [talk-au] secondary_link

[Liz]

On Sun, 9 Mar 2008, Stuart Robinson wrote:
 Links are by default oneway, I think that's what the other person is
 getting at.

 stuart.

so the use of secondary_link was possibly a shorthand to avoid oneway=true  ??


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Re: [talk-au] Highway Classification Issues

[Ian Sergeant]

Darrin Smith [EMAIL PROTECTED] wrote:

 When I read one part of the OSM wiki I see it talking about classifying
 highways purely by their physical characteristics
..
 The majority of pages talk about classifying roads by their state
 funding designation and or highway reference which is fine because
 these are pretty easy to explicitly define.

There is little doubt that the original highway definitions corresponded to
the classification system in the UK.  The
primary/secondary/tertiary/unclassified correspond pretty closely to the
road classifications there.

The arguments over physical or administrative classifications lie around
the edges of the discussion in the UK.  Some people thinking an 'A' road in
certain sections, may be secondary, or some such.

Anyway, rest assured this is a live debate.  Check out
http://wiki.openstreetmap.org/index.php/Proposed_features/Highway_administrative/physical_descriptions

 discussion of reference definition, vs physical definition

In some urban areas in Australia, the reference definition can work quite
well.  In Sydney, Motorways correspond to motorways, trunk roads correspond
to metroads, and residential/unclassified to surburban correspond to
streets going nowhere.  This only leaves primary/secondary etc to be
subjective to a certain extent.

However, in rural areas of NSW, the system doesn't work so well.  If you
use the reference method, you will find that there are a handful of state
highways, a couple of auslink roads, and that leaves 99% of all the roads
without a reference classification.  This would dramatically reduce the
usefulness of the resulting map to use a reference classification.  Most
roads would look the same.  Many main routes between towns have no
reference classification at all.

It would be nice if Australia had a reference system that would work
comprehensively.  It doesn't, and that leaves us always requiring a certain
element of subjectivity.

I would say - if there is a workable reference system for a particular
area, then it is best to use the reference system, and make a
correspondence to the OSM types.  Document the area and the reference
system on the wiki, and coordinate a discussion to ensure there is a
consensus for that area.

Where there isn't a workable reference system - where that would leave far
to many roads unclassified, or through roads not indicated as through
roads, then some subjectivity has to be used.  Not just the physical
propoerties of the road, but also whether it is the main linking road
between centres, etc.  The current wiki guidelines for Australian Road
Tagging are the result of previous discussions to try and pin this down,
and try and standardise as much as possible where no reference system will
work.

If you can come up with a practical, yet unambiguous and objective, system
for all of Australia, that would be great.  Short of laying seige to the
roads departments and councils, I don't think that is going to happen.  I'm
sure if you have ideas for improvement, or a workable reference system for
Adelaide, then you just need to convince people of the benefits, and update
the doco.

Ian.


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Re: [talk-au] Adelaide Highway Classification (was: Highway Classification Issues)

[Darrin Smith]

On Mon, 10 Mar 2008 11:52:00 +1100
Ian Sergeant [EMAIL PROTECTED] wrote:

 Anyway, rest assured this is a live debate.  Check out
 http://wiki.openstreetmap.org/index.php/Proposed_features/Highway_administrative/physical_descriptions

That's an interesting page, good to see people are addressing that
issue on a global level. Should that proposal go through it
automatically eliminates one of the options as 'valid' ... Shall have
to keep an eye on it.

  discussion of reference definition, vs physical definition

 Ian's comments

OK, in a sense it's good to see people as unsure as I am :)

 However, in rural areas of NSW, the system doesn't work so well.  If
 you use the reference method, you will find that there are a handful
 of state highways, a couple of auslink roads, and that leaves 99% of
 all the roads without a reference classification.  This would
 dramatically reduce the usefulness of the resulting map to use a
 reference classification.  Most roads would look the same.  Many main
 routes between towns have no reference classification at all.

Perhaps NSW will one day get it's funding to finish the MABC roll-out,
that might help a lot, but yes until then I don't envy your position.
South Australia is a little better off with a nicely defined set of A 
B roads to guide things along.

 It would be nice if Australia had a reference system that would work
 comprehensively.  It doesn't, and that leaves us always requiring a
 certain element of subjectivity.

3 States have (TAS, VIC, SA), 2 are part way there (NSW  QLD), it's a
start :)

 I would say - if there is a workable reference system for a particular
 area, then it is best to use the reference system, and make a
 correspondence to the OSM types.  Document the area and the reference
 system on the wiki, and coordinate a discussion to ensure there is a
 consensus for that area.

Right this is where I kind of got to with Adelaide, I guess my first
email was a call out to start such a discussion so I'll change the
subject to reflect that...

 If you can come up with a practical, yet unambiguous and objective,
 system for all of Australia, that would be great.  Short of laying
 seige to the roads departments and councils, I don't think that is
 going to happen. 

Yeah, that's a good dream that one :) 

 I'm sure if you have ideas for improvement, or a
 workable reference system for Adelaide, then you just need to
 convince people of the benefits, and update the doco.

OK, to take this a step further I'll start the ball rolling in Adelaide:
(As we get a consensus I'll write a Adelaide/South Australia Wiki page
to reflect the decisions, I'm happy to do that)

1) Trunk Roads in City

I propose that all A routes in Adelaide and only A Routes are
labelled trunk. 

I can understand some hesitation from people with respect to the A22,
parts of the A16 because they are low quality roads, but if we're going
to tag to a reference pattern they need to fit.

2) Definition of rural vs city area

I propose that the area bounded by lines joining Two Wells, Gawler,
Birdwood, Mount Barker, Willunga, Aldinga and the Coast line are
defined as City area, and that areas outside these are considered
Rural (We can define other city areas around Mount
Gambier/Whyalla/Whatever if people have definitions?). I think the
current Rural definitions as provided on the Wiki are pretty close to
spot on for these areas.

3) Primary Roads in City:

There are about 5 B Roads inside the definition of the city area,
otherwise there's a whole bunch of roads in the city itself which
server the cross-city tasks the road definition suggests these should
be. However I think there are currently way too many roads in Adelaide
marked as primary which AREN'T serving significant cross-suburb
purposes (Prospect Road is one that immediately comes to mind). I would
like to suggest we the mappers of Adelaide draw up a list of Primary
roads which are the only ones that should be marked primary.

4) Further levels: For later, a few steps at a time :)

I'm particularly would like input from those guys mapping lots
of Adelaide with me (jackb, justcameron, adhoc?) since you guys and I
will tread on each others toes if we're not seeing eye-to-eye.

-- 

=b

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