[Talk-us] Fwd: [Tagging] Proposal for standardization of sidewalk schema (+ import)

Martijn van Exel m at rtijn.org
Tue Aug 2 22:12:16 UTC 2016


The discussion threads got disconnected between tagging and talk-us,
forwarding my response to talk-us.
Martijn van Exel
http://mvexel.github.io/

---------- Forwarded message ----------
From: Martijn van Exel <m at rtijn.org>
Date: Tue, Aug 2, 2016 at 4:09 PM
Subject: Re: [Tagging] Proposal for standardization of sidewalk schema (+
import)
To: "Tag discussion, strategy and related tools" <tagging at openstreetmap.org>


Frederik,

On Tue, Aug 2, 2016 at 3:39 PM, Frederik Ramm <frederik at remote.org> wrote:

> Hi,
>
> On 08/01/2016 11:35 PM, Meg Drouhard wrote:
> > Hello,
> >
> > Our team is proposing a standardization of sidewalk tagging conventions
> > in OSM to simplify pedestrian network annotations and better represent
> > the physical reality of sidewalk ways.  This proposal is particularly
> > concerned with features of sidewalks that may aid or impede travel for
> > people with limited mobility.
> >
> > Our schema proposal is available
> > here:
> http://wiki.openstreetmap.org/wiki/Proposed_features/sidewalk_schema.
>
> As written on the imports list, I think that separate mapping of
> sidewalks will not, and should not, be the norm; they should be possible
> where it helps modelling a complex layout but you shouldn't rely on them.
>

I think that this is what we are here to discuss, and in light of that
using prescriptive wording ('shouldn't') is not helpful. It suggests that
you possess some kind of special authority deciding on tagging schemes that
you do not. Furthermore your tone suggests that people new to this
discussion or to OSM are to subject themselves to that perceived authority,
rather than welcoming them by using a tone of curiosity and willingness to
learn from people with an outside perspective. Altogether not helpful for
having an open discussion.


> In the past, we've had a number of projects aimed at helping older
> people or those with impaired vision or movement to navigate cities.
> These were often driven by some university or city department with
> limited funding and a limited run time, resulting in often shabby
> imports of footway-sidewalks ("the community will fix it, surely"), so
> that the university/department could quickly show off their prototype
> and then forget about everything and go on with their lives.
>
> This is not what brings OSM forward; these people have not kick-started
> anything but just hijacked OSM for a short-term goal.
>

Again you are being suggestive -- do you expect this initiative to fail
like similar ones preceding it? Why can we not draw positive lessons from
the past rather than expecting new initiatives to fail before they even get
started? Or am I misinterpreting you entirely here?


> Mapping sidewalks as individual geometries is the most
> data-consumer-friendly of all possible approaches; configure your
> renderer to use only footways and bam, it works.
>
> However, the result will be as system that works *only* where separate
> footways are tagged, and it is highly unlikely that this will happen on
> a global scale. A good pedestrian routing schema *must* cope with
> not-explicitly-mapped sidewalks.
>
> But mapping sidewalks as individual geometries puts considerable burden
> on the mappers who want to work with the data in an editor.
>

The tools have always evolved with the ever expanding tagging schemas. This
is just a red herring and I wish we would stop using it as an argument
against new things folks come up with to map.

>
> There's also the question of how to link a separately mapped sidewalk to
> the street it belongs to, so that proper routing instructions can be
> generated (instead of "follow unnamed footway for 500 metres"). And the
> question of how rendering should treat these sidewalks.
>
> Reading material for past research and discussions (some of this is
> German only or Germany-heavy I'm afraid) e.g.


> * https://lists.openstreetmap.org/pipermail/talk/2015-April/072613.html
> (Roland Olbricht on routing suggestions)
>
> * Nathanel Lang's bachelor thesis in which he synthesizes a routing
> graph with separate edges for left/right sidewalk even when none exist
> in OSM https://github.com/Nathanael-L/pedro
>
> * Long discussion on Austrian list
> https://lists.openstreetmap.org/pipermail/talk-at/2014-February/006402.html
>
> * Micha Meier's work in Graz, Austria - Project "Access2Life"
> http://wiki.openstreetmap.org/wiki/User:Species/Access2Life with
> detailed tagging schema and even specialized JOSM presets and styles
>
> I'm Cc'ing Roland and Micha explicitly because I don't know if they are
> on this list.
>

The fact that this is all pretty German language centered sums it all up.
The topic has perhaps been discussed over and over in your language, spoken
by ~ 1.4% of the world. That doesn't mean other communities will
necessarily come to the same conclusions, or that they may not have
valuable input that perhaps the German community could even learn from?

>
> There's also people discussing whether to start mapping certain highways
> as areas and it is unclear what, if anything, this means for sidewalk
> mapping.
>
> I'm not a friend of separately mapped sidewalks but I can live with
> people mapping them if they desire. Importing them, however, is a whole
> different ballgame that should only be attempted after careful
> evaluation of past problems and previous work.


I do not think anyone proposing this would not be prepared to do this, and
the background you provide could definitely be helpful, if it were
presented in less of a context of authority and condescension.

Martijn
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