On 3 Jun 2019, at 09:15, Stuart Reynolds 
<stu...@travelinesoutheast.org.uk<mailto:stu...@travelinesoutheast.org.uk>> 
wrote:

As Jerry says, from a routing perspective having lots of separate footpaths 
doesn’t help when you can just walk across the road at any given point. 
Boulevard-type roads with central grassed areas are very similar. If you aren’t 
careful you end up with a number of artificial crossing points, which is wrong.

On the flip side, though, what we also have is a significant number of roads 
that are currently defaulting to walking when they cannot be walked. I have had 
to to tweak the A500 around Stoke, for example, and there were similar problems 
on the A4150 around Wolverhampton Bus Station. When I find these, I don’t have 
the time (or local knowledge) to edit entire stretches of road, so I tend to 
just edit the slip roads and the mainline where I am having the immediate 
problem.

From a personal point of view I would therefore rather avoid separate footpaths 
where they are not distinct, but at the same time we need to improve a lot of 
urban high speed roads that are not walkable.

Regards,
Stuart


On 2 Jun 2019, at 14:10, SK53 <sk53....@gmail.com<mailto:sk53....@gmail.com>> 
wrote:

I recently 
extended<https://www.openstreetmap.org/way/4072429#map=18/52.22564/0.11783&layers=N>
 some already mapped pavements in N. Cambridge. I'm not really a fan of the 
current approach because I don't think it works particularly well, and I'm not 
aware of any good routers using this type of data for wheelchairs.

The problems I see (and I've said this before):
The scope for missing interconnections is trebled.
It's more or less worthless unless done systematically (places like university 
& hospital campuses are viable from this viewpoint.
In Britain, at least, it requires introduction of many arbitrary crossing 
points to allow any kind of sensible pedestrian routing (i.e., not 
well-supported by on-the-ground features such as dropped kerbs & tactile 
paving). You can see the ones I felt it necessary to introduce around Roseford 
Road & Perse Way. Note that many crossings, e.g., at the Harris Way/Perse Way 
intersection are not complete.
It breaks existing applications. The reason why I noticed the issue in North 
Cambridge is that the Traveline South East app started giving me unfeasibly 
long times to walk to a bus stop. It turned out that it routed me all the way 
along a pavement to Histon Road & then back along Histon Road adding a good 500 
m to the journey. This was because the original mapping just stopped without 
connecting the end of the pavement to anything.
I'm not completely convinced that wheelchair users, blind people etc can put 
the same degree of trust in this type of data as the ordinary pedestrian can 
for current pedestrian routing. My feeling is that the information really needs 
to be tailored to the user: there's a massive difference between how a powered 
wheelchair or mobility scooter and a manual/pushed wheelchair can cope with 
non-flush kerbs for instance.
I'm not sure if anyone has done any work to show how separately mapped 
sidewalks can be merged with the main highway to provide generalised pedestrian 
routing such as we have now.
Probably to be useful in the UK, all driveways should be mapped too (as in 
Andy's dev server example): in my experience of pushing my late mother around 
in a wheelchair driveways are often much better than many shoddy dropped kerb 
installations.
Naming of sidewalks can create problems (although it can also resolve them in 
cases where the two sides of a street have different names).
It's a pig to survey well in places where dropped kerbs have not been installed 
systematically (as in my Cambridge example).
On the plus side:
It allows more relevant details of pavements to be tagged (width, surface etc).
The current sidewalk model is probably much more appropriate in countries with 
specific legislation preventing pedestrians crossing roads at any other than 
designated crossing points (jay walking).
It's always been good publicity for OSM: even if actual real usage is limited.
Inevitably OSM will move in the direction of capturing more information & this 
is just one example.
I guess I would have preferred : sidewalks to be mapped with a key other than 
highway (something analogous to area:highway); more research to be done on ways 
to post-process the data (in both directions from 
highway=footway,footway=sidewalk and from sidewalk=*); and good references for 
actual user experience of wheelchair routing using separately mapped sidewalks. 
One way to have our cake & eat it would be to use both sidewalk= and have 
separately mapped sidewalks & allow the consumer to choose which to use, 
although the current sidewalk=separate does not say if its both, left or right. 
Personally I think this is still reasonable in the context of one feature one 
element; sidewalk is an attributive property of the street and potentially 
difficult to derive without resorting to convoluted approaches (such as 
relations).

In summary the problem from my perspective is that mapping them separately can 
often make OSM less useful, whereas most other mapping of additional features 
enhances OSM incrementally.

Jerry
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