[Tagging] Tagging of larger surfaces for rendering and routing

[Marc Gemis]

IMHO, the value of the highway tag should define its use, not the
surface from which it is made.
So highway=pedestrian (or service or ...), surface=grass; area=yes
makes more sense to me

(or would you start defining highway=paving_stones, cobblestones, etc.
as well ?).

A renderer could look at the surface tag to colour the area. No reason
to start inventing new values for the highway tag.

regards

m

On Sun, Aug 14, 2016 at 10:21 PM, Stefan de Konink <stefan at konink.de> wrote:
> Hi,
>
>
> As followup for:
>
> http://forum.openstreetmap.org/viewtopic.php?id=55457
> https://github.com/gravitystorm/openstreetmap-carto/issues/2282
>
> The problem;
>
> Consider a large area that doesn't have explicit roads. It could be a field
> of grass or a sahara of sand. Typically such surfaces are tagged as landuse
> with objects such as housing on top. It surely looks good on a rendered map,
> but for routers, journey planners, topology cannot be inferred by the node,
> way and relation model. Secondary the wiki[1] suggests that routers should
> only use highway=* and junction=*, which makes sense.
>
> As specific example on the forum I am micromapping a campingplace and would
> like to use highway=service to access camp_site=pitch. In real life this is
> sometimes a field of grass passing by pitches that are also fields of grass
> with some barrier=hedge around it to separate it from the field.
>
> As can be seen in the github issue the current rendering of a
> highway=service, area=yes results in a white void where the landuse=grass is
> ignored. Cartographers throw in the argument that the map is not a
> vectorised version of satellite imagery. Which is true of course, on the
> other hand: is a field of grass is not the same as a paved plaza tagged as
> highway=pedestrian, area=yes while, the net effect for an unpaved field is
> generally the same.
>
>
> The result;
>
> I would prefer that the map looks like its landuse, but this specific
> landuse's primary intention is facilitating access to properties and other
> objects. For journey planners this area topology folds back to a single
> vertice where from multiple locations, sharing a node with the osm-way
> acting as area, can be reached.
>
>
> My proposal;
>
> Considering that in the camping site example highway=service is primary used
> to facilitate access to pitches, I would like to see highway=service,
> surface=grass, area=yes possibly in combination with landuse=grass as
> indication to render this surface not as a white void, but as a green field.
>
> The alternative might be to define a user defined highway tag such as
> highway=grass.
>
>
> My current workaround;
>
> highway=grass, area=yes is not rendered which basically gives me the best of
> all worlds. Rendering is done by the underlying landuse, routing is
> facilitated by the highway=* match.
>
>
>
> Matthijs suggested this was a better fora to discuss the issue, than the
> carto github issue tracker. So here I am.
>
>
> Stefan
>
>
> [1] http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing
>
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