[OSM-talk] Cycle route improvements

[Ben Laenen]

Hi all, and Andy in particular,

as the past weeks went by while entering cycle routes for Belgium into 
OSM, I've come across several issues. It's a big mash-up of needed tags 
and improvements, so here goes...


* Tagging of alternate routes:

Some routes have shortcuts, or in general alternate ways (e.g. for when 
a route is blocked due to the weekly market day, it's possible to 
follow another signed route, or sometimes there's an alternative for 
cyclists who don't like sandy roads). These routes are generally marked 
as a dashed line on most maps I've seen, to make sure it doesn't look 
like the main route. I guess a tag as "route_special=alternate" added 
to the route relation works for that to make that happen. I don't think 
a "route_special=shortcut" is needed, after all, it's just an 
alternate.


* Tagging of connection routes:

Connection routes are routes which bring you either from one route to 
another one, or from a route to an interesting location like a city 
center (or the other way around). These routes also need to look 
differently on the map. In the maps I've seen they usually do it by 
marking them with a different colour, but I understand that may be a 
problem with different networks on one map, so maybe a dotted route 
perhaps? Anyway, I propose a "route_special=connection" tag for these.


* Rendering when different networks (local, regional, national) are on 
the same way:

It's somewhat solved on the highest zoom in the cycle map by having 
transparent ways, but in lower zooms it gets messy since it's 
apparently a random one that "wins" for each section. I've seen two 
different approaches on the maps I've seen so far:
- alternate colours: the section are coloured e.g. 
red-blue-red-blue-red-blue (but becomes a problem for more than one 
network)
- different networks = different line width: this is my personal 
favourite solution for this: make national routes wider than regional 
ones, which are again wider than local ones. So you can easily show 
three routes on one way if needed. You only need to make sure to draw 
to thinnest routes last of course :-) This solution also works nicely 
with dashed lines like mentioned above.


* Preferred colour for the route:

Now let me first say that this isn't for giving all national routes the 
colour "green" for example instead of red in country X. I want to use 
this to distinguish routes on the same level which can run into each 
other.

I don't know if something similar exists in the UK, but over here it's 
needed for our local routes: these aren't really a network, but they're 
themed routes which make loops, and those loops overlap each other, 
sometimes two or more of them follow the same road for a short 
distance. So, when making them all the same colour on a map it becomes 
a route cloud in which you can't see the exact loops anymore, and you 
have no idea anymore how the routes go.

Again, this is usually solved by different colour on maps, so that's why 
I propose here an "abstract" "preferred_colour=X" tag, where X could be 
a number between 0 and 5. The renderer can then choose its palette and 
assign colours to them which suit the map and which don't clash with 
the colours of other networks (like all shades of blue for local 
routes, shades of red for national routes etc). The person entering the 
route in OSM then just need to make sure that no two routes of the same 
colour overlap.

The problem of having two different coloured routes of the same network 
level on one road is then solved by alternating the two colours on the 
shared road.


* Route starting points:

As the title says: this is for points where a route starts (the local 
loop routes for example all have a starting point), usually near a 
parking, sometimes at a symbolic place after which the route was named.

For rendering this could be a big dot, together with the name of the 
route and a reference if it has one (that also happily solves the 
current issue of not seeing the names for those routes which have no 
reference numbers). (possible in the same colour as defined 
by "preferred_colour" when two routes start from the same place).


Okay, I guess that's a nice set of issues to start of with :-) Any ideas 
or opinions?

Greetings
Ben