[Talk-GB] Paths and Footways

ajt1047 at gmail.com ajt1047 at gmail.com
Sun Aug 16 19:06:20 UTC 2015

On 16/08/2015 18:26, Rob Nickerson wrote:
> Hi all,
> Given that paths and footways are now rendered the same way in the 
> default OSM style I wonder whether it is time to look at how the map 
> can provide better information.
> For rural mappers tagging a path/footway as unpaved surface results in 
> it having less prominence on the map. As most major public rights of 
> way are unpaved this makes these paths harder to view on the default 
> OSM map.
> Some possible changes:
> 1. Render all paths/footways that are tagged as 
> designation=public_footpath (or other RoW) more prominently.

Are we talking about OSM-Carto here?  That's by definition an 
international style and I don't think that rendering 
designation=public_footpath outside of England and Wales makes a lot of 
sense, although it would make sense as a "local style" for England and 
Wales (you've mentioned that as a possibility recently).  I don't know 
how far the "core paths" network in Scotland has progressed either on 
the ground or in OSM, but perhaps some variant based on that could work 
up there.

> 2. Render those paths/footways that make up a long distance walking 
> route more prominent (relation data).

That makes some sense, but OSM-Carto's biggest problem is that a number 
of the changes over the last year have been dedicated to making 
well-mapped central European urban areas "look nice" at the expense of 
the rest of the planet.  There's a lot more that would have to be done 
to make OSM-Carto usable for e.g. rural footpaths outside cities.  
There's chapter and verse already in github issues (including "not 
rendering foot=yes access=private ways at some zooms" and "not rendering 
major landscape features such as abandoned railways"), so no need to 
repeat here, but a lot of the last year's changes would need to be 
reversed to make the style usable for that purpose.  This doesn't make 
the changes "wrong" or "bad" of course; every map style has to decide 
what to show and what not to show - try and show everything and you end 
up with a complete mess.

> 3. Render based on another tag such as trail visibility [1] or maybe 
> we need a brand new tag to indicate path dominance (like we have 
> motorway/trunk/primary/etc for roads).

I'm not sure there's "room" in the presentation of footway etc. for 
this.  I do render (using a modified style based on osm-carto from some 
time ago*) designation and width, but do throw 
footway/bridleway/cycleway/path into the same bucket. 
http://imgur.com/JQGc0YR is an example of that (compare with 
http://tile.openstreetmap.org/13/4061/2663.png ) - red means "public 
footpath", blue means "bridleway", grey means "no designation"; and dots 
mean "narrow" and dashes mean "wide".  I suspect that trying to display 
the many values of trail_visibility would be difficult or impossible 
(and what should be the default value where it is not recorded?).

One approach (if we're just talking about raster tiles here) might 
involve transparent overlays**, though that means even more data 
downloaded over what is likely to be a dodgy cellular data connection if 
you're in the middle of a field.  If we're not (and if we're not 
starting from OSM-carto, we don't need to) then other people have 
already suggested something else entirely***.


Andy (SomeoneElse)

* See https://github.com/SomeoneElseOSM/SomeoneElse-style and 
https://github.com/SomeoneElseOSM/openstreetmap-carto-AJT .  I'm not 
suggesting this is a "style for all rural map users" of course (it'd be 
rubbish for cyclists, for example).  It's just included as an example of 
the problems of displaying yet more different elements in the data.

** Like the Met Office use on their OpenLayers site (but better than 
that, obviously)

*** The author of http://blog.systemed.net/post/13 for one.

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