[Tagging] Sidewalks and cycleways as tags vs as extra lines

["Christian Müller"]

> Gesendet: Montag, 15. Januar 2018 um 15:47 Uhr
> Von: "Fernando Trebien" <fernando.trebien at gmail.com>
> An: "Tag discussion, strategy and related tools" <tagging at openstreetmap.org>
> Betreff: [Tagging] Sidewalks and cycleways as tags vs as extra lines and StreetComplete
>
> The wiki also says that, when mapping a parallel cycleway as a
> parallel line, one should not use the cycleway=* tag on the motorised
> way.

This is indeed problematic.  A lot of use cases preprocess osm data and
filter out separate/parallel cycleways and paths.  It would be nice to
have a compromise in the wiki as to suggest that a minimum of tags on
the motorized way should remain _even if_ a parallel way exists.

Imho it is not necessary to duplicate the whole tag set of the primary
subject (parallel cycleway) on a secondary (highway).  But a simple
(read ideally one or two tags) attribute that enables data users to
bisect a set of motorized ways by the sidewalk or sidepath property
may simplify a lot of queries.


To be more direct, I'd suggest to use

cycleway=* ( cycleway:left=* cycleway:right=* | cycleway:both=* )
sidewalk=* ( sidewalk:left=* sidewalk:right=* | sidewalk:both=* )

as the maximum additional tags to use on a motorized way,
if a parallel way (or ways) exist for the cycling and/or
walking infrastructure.

cycleway=* and sidewalk=* should be marked deprecated/legacy,
in favor of the colon variants.

Some people use "sidepath" instead of "cycleway", but if the meaning
of "sidepath" is to be coherent with the established tag values of
highway=cycleway|footway|path, then "sidepath=val" tag should rather
be defined to be a convenience shorthand for saying "cycleway=val"
_and_ "sidewalk=val".

A refining segregated=* tag is rather specific to the main subject
(the cycling/walking infrastructure parallel to the motorized way),
so its use on the motorized way should be discouraged just as well.


Imho, in the long run, this could converge to sth like

( cycleway:left=* cycleway:right=* | cycleway:both=*,
  sidewalk:left=* sidewalk:right=* | sidewalk:both=* ) |
( sidepath:left=* sidepath:right=* | sidepath:both=* )

.. with the pipe symbol informally to be read as exclusive or.

Main purpose of these tags is to characterize accompanying roadwork,
not planning mistakes or under-dimensioning (wild paths along roads
are often considered planning mistakes).  So tagging and informing
about wild paths _using these tags_ should either be discouraged,
or done with dedicated "unofficial" or "wild" tag values.


Among cycleway, sidewalk, sidepath, the vocabulary may be extended
using sideride, which may be a more appealing synonym to cycleways
running alongside roads than "sidepath".  Adding this term to the
list, it may be easier to see, /why/ coherence in the definitions
of sidepath=* and highway=path is worth striving for.


Greetings
cm