[Tagging] Road hierarchy

Paul Allen pla16021 at gmail.com
Sat Aug 10 11:35:29 UTC 2019

On Sat, 10 Aug 2019 at 11:42, Julien djakk <djakk.geographie at gmail.com>

> Classifying roads should be the same all over the world ! :O

In an ideal OSM, tagging ANYTHING should be the same all over the world.
Sadly, people
sometimes insist on fitting square pegs into round holes instead of coming
up with a new
value or even a new key.  I shudder every time I see "In OUR country we use
this tag
completely differently."  Sometimes this list is partly to blame for that -
the last time I
can think of was about tagging polders, with some insisting that existing
tagging be
used for a feature that isn't well-described by them.  But see below...

The highway tag shuffles administration grade (in England for example
> or for motorways), physical characteristics / abutters (example :
> residential, motorway), access, and importance (commuting and
> long-distance trip). I think the highway tag should be split into
> those 5 features : admin_level, abutters, access, commute_importance
> and long_distance_importance (by experience, there should be 6 levels
> for importance, from the cul-de-sac road to the main artery).

Hindsight is 20-20. There's a famous saying in computer programming "Plan
to throw
the first one away, you will anyway."  When you develop something new, you
along the way.  Often you find you've painted yourself into a corner and
had you
known at the beginning what you know now you'd have done some things
That's how it is with many older (and some newer) OSM tags.  Had we known
back then
what we know now, some of our tags would look a lot different.

With your proposed scheme there are going to be some people who think it's a
good idea and others who will see all sorts of problems with it.
Eventually, after
a lot of discussion, all might agree on something vaguely similar to your
(which would be a lot different to what we have now).  I doubt it, but it's

Even if we come to an agreement, the problem is implementing it.  It isn't
a one-to-one
mapping, far from it.  And that means EVERY road that has been mapped will
have to
be re-examined in order to figure out how to tag it.  With a one-to-one
mapping a
mass edit would be possible, but with this it's going to be a lot of work.
A hell of
a lot of work.  There are far too many POIs that are as-yet unmapped to
divert all
our effort into retagging every highway in the world when what we already
have is,
although not ideal, reasonably good.

If you ever managed to get this flying pig off the ground (you won't) then
there's the
problem of decorating the wings.  Even if you got full agreement from the
list, and
a commitment by every mapper to remap every highway, you also have to
the carto people to render it.  And the editor people to support it.

There are only two ways you could make this proposal happen.  One is
forking OSM
and convincing enough people to join you that you can remap every highway
in the
world before you all die of old age.  The other is to invent a time
machine, go back in
time and present good arguments to persuade people to invent better
tagging.  I'm
not sure, but I think you might have more chance of success if you go for
the time

What you have is another way of illustrating that one of the main purposes
of this list
is to try to use our collective knowledge and experience to avoid
introducing tags
with problems or we'll end up with less-than-ideal tags like our highway
OSM evolves and, like biological evolution, that means taking what we
already have
and tinkering with it a little.  Big changes aren't possible, just minor
changes that
result in a design that is far from perfect but is good enough.

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