[Openstreetmap] Re: road names

Tom Carden tom at tom-carden.co.uk
Fri Nov 18 00:49:58 GMT 2005


On 11/17/05, Alex Mauer <hawke at hawkesnest.net> wrote:
> Tom Carden wrote:
> > On 11/17/05, Alex Mauer <hawke at hawkesnest.net> wrote:
> >
> >>I don't think the left/right distinction is terribly useful. It's nearly
> >>always sufficient, both for navigation and for ease of data entry, to
> >>know what block a particular number is on
> >
> > We don't model blocks though, we model street segments.
>
> Right...but either way, left and right are not very useful.  And which
> side's left and which is right?
>

Depends on the order the points were entered, but it's trivial to
define a convention for this if we need one.

> If I'm on Foo Street, I don't much care which side #1542 is on, and
> which side #1565 is on.  Getting to the correct block of the street is
> sufficient.
>
> > Except that left/right seems essential if you want to draw it like
> > maporama does?
>
> If we take it as read that that aspect of maporama's visualization is
> useful, yes.  I don't think it is.

Fair enough.

> Again, it doesn't matter which side
> of the street the numbers are.
>

Except if they don't match up by block, like most European streets -
in which case you need a range for the odd side and a range for the
even side.

> > I'm not interested in "blocks", if I can think of a general case which
> > supports all the subtleties people are describing.
>
> For navigation or "object selection" (e.g. clicking on a street section
> in roadmap) blocks are more interesting than segments or whole streets,
> really.  "All segments between two junctions/intersections" is what I
> mean by "blocks", btw..

If that's what you mean by blocks then sure, I agree with this part,
and it's a sensible way to select stuff.

>
> > So you just specify numbers at the start of the first curve segment
> > and the end of the last one.  No big deal.
>
> Which end is the start, which is the end?
>

The first node clicked on and the last node clicked on, when you
select a "block" as you've described it.  The first and second nodes
in a segment, otherwise.  Not that it matters, I can think of a few
ways the interface would work for labelling in a maporama way (if we
wanted to) which wouldn't require the user to know the difference
between left and right for a segment.

>
> > But OSM almost certainly won't have units smaller than the entire
> > road, except for segments, for the foreseeable future.
>
> Well, it doesn't have entire roads yet, either...

The internal model does, and the API might (I haven't checked) and the
interface will follow soon.

> but before saying that
> roads are the smallest useful unit above segments, as the original post
> and immediate replies seemed to say, other things should be considered.
>

But do the other things need to be modelled explicitlty in the
database?  Sounds like they're trivial to infer in the client, as you
described for blocks above.

Tom.




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