[OSM-talk] Sidewalk symmetry

Clifford Snow clifford at snowandsnow.us
Tue Apr 24 00:17:19 UTC 2018

As someone who as mapped sidewalks both as metadata to an existing road and
as separate ways, my recommendation is to map as separate ways. Let me
explain why I recommend separate ways over the metadata approach.

Communities are starting to put emphasis on alternatives like public
transportation, cycling and walking to driving for a number of reasons, For
example traffic congestion. green house gases, and health benefits to name
three. There is also a segment of the population with limited mobility
issues that need to commute via wheelchairs and public transportation. All
of this requires some form of routing. Routing via metadata breaks down at
the intersection, especially complex ones. There is the routing problem
that Mateusz Konieczny mentioned of what to call the sidewalk, but research
scientists believe they can use the spatial proximity of the road to give
instructions such as "walk on the left side of Main Street towards..."

Separate ways also have the advantage of being able to capture data on the
physical aspects of the way, such as surface material, width, smoothness,
tactile pads, kerb cuts, etc.

I've talked to some GIS folks about their sidewalk data. Some have some
beautiful polygon sidewalk data. But none of the data is any good if we
can't route. It's only purpose is to serve as a inventory of sidewalks.

The one advantage to the metadata approach is speed. It's much quicker to
add sidewalk=left/right/both/none. But like the cities standalone sidewalk
data, it doesn't route all that well.

Jmapb - if your goal is just to map sidewalks as inventory - then use the
metadata approach. I can attest that it is easier. But if you want someone
to use the data, then map it as separate ways.

There is a good website that explains the separate way approach
opensidewalks.com. I know the people who put it together and they convinced
me it's the better approach.


On Mon, Apr 23, 2018 at 1:26 PM, Mateusz Konieczny <matkoniecz at gmail.com>

> On Mon, 23 Apr 2018 19:25:12 +0200
> Tobias Knerr <osm at tobias-knerr.de> wrote:
> > Comparing the mapping styles solely based on ease of mapping would
> > only make sense if separate ways were able to express the same
> > information contained in sidewalk tags.
> Note that some information may not be expressed (or extremely hard)
> with sidewalk tags.
> For added fun, some people map sidewalks in even greater detail, using
> area:highway (and sometimes forget to add either sidewalk tag or
> sidewalk mapped as line, what is also causing problems).
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