Hi, Seems like we have a fair bit to discuss if we ever manage to sit down over a beer. I agree, however, that overall most of these differences are unlikely to make a substantial difference to the map.
However, returning to the two key points on cycle routes in AU. Firstly, mapping personal preference "unofficial" cycle routes. We both seem to agree that there are potentially a large amount of these. Every road on the map and track on the map could be somebody's cycle route from somewhere to somewhere else. We've seen on sites like bikely how prolific these cycle routes can be, with around 9000 cycle routes crossing the Sydney area alone. We agree that it wouldn't be a good thing if there were this many cycle routes in OSM. Once we start allowing such routes, neither of us have any idea how the number will be contained. You believe that this shouldn't stop us, because the community will work out a way if and when it becomes an issue, and it may never actually become an issue in OSM (with more sophisticated mappers than bikely :-) I believe this is a very slippery slope, and we're doing the project a disservice by introducing unverifiable data without any guidelines for how we would limit its use. I think we would need a broad consensus to introduce cycle routes based on individual preference, as well as documentation on how when and how they would be used, and reasoning on how we can avoid the obvious pitfalls. We haven't seen any of these yet. My issue here is purely the slippery slope and verifiability. I may actually prefer a cycle map produced by OSMers producing cycling maps by survey then the poor excuse for routes coming from "authoritative sources". However, I think the best way of achieving this is to add the infrastructure, and rely on automation to produce preferred routes. Otherwise I see it turning into a mess. Secondly, the subjective evaluation of published cycle routes. Here I think I'm definitely on shakier ground, but I'd like to see a good solution. There are three different levels of institutions that publish cycle routes. State government authorities, local government authorities, and local cycling groups. In general, I think adding these routes to OSM is a reasonable endeavour, however, we should reconsider in a three circumstances. 1. Where the path or road referenced by the route doesn't exist or isn't accessible. I know this sounds a little odd, but in quite a few cases the route is either out of date, or the infrastructure is still in a planning phase, or it has been removed or damaged beyond any utility, or it has been incorporated into private property, or signs and barriers on the ground exclude cyclists. This is a direct appeal to the "on the ground" mantra. The route can be defined on the "official" website as a cycle route, but why would be included in our data if you can't actually cycle on it? To include this data on the basis it is "official", would seem like bloody-mindedness. 2. Where the path or road referenced is indicated by a sign only, and no cycle facilities or infrastructure exist on the ground. Quite simply, in Australia the existence of a bicycle sign doesn't indicate a route. Map the sign if you like, by all means, but don't map a cycle route unless there is some other supporting evidence of a cycle route. 3. At the furthest extreme, where there are no cycle facilities on a section of a route, the route is clearly not residential or off-road, and the road is no better as a route that the roads either side of it (not quicker, not safer, not less trafficked, not flatter) then I think we should consider omitting it. If the cyclist is no worse off just plotting the more direct road linking two cycle route sections, then we're adding nothing of value. Again, OSMs strength is current, on-the-ground analysis, and we should make use of it. The official cycle maps are easily accessible to those who want the unabridged version. I'm aware of the contradiction that you see between not including personal preference cycle routes, and yet using subjective analysis to determine whether to include official ones. However, I'm hoping some of the contradiction is removed when you look at the reasoning. Ian. On 27 April 2012 17:08, Steve Bennett <stevag...@gmail.com> wrote: > On Fri, Apr 27, 2012 at 12:58 PM, Ian Sergeant <inas66+...@gmail.com> wrote: >> Cycle and walking routes get relocated, torn up, fences put across them. > > ...and there's no way we can keep up with such changes. > >> Park names? The name that is on the park prevails - quite often >> different to other sources. > > No way. Signage is frequently a low priority from organisations that > maintain parks, trails, etc. Just on bike paths, I've seen as many as > 3 different names signed for the same route - in addition to names > provided on websites or other publications. > > The name on a sign at the physical site is just one name amongst many. > >> On the ground doesn't mean we can't use other sources. It just means that >> when sources clash, we defer to what is on the ground. This is in contrast >> to Wikipedia, for instance, which will use a secondary source to determine >> what to include. OSM will always choose what is physically present, on the >> ground. > > It sounds like we don't disagree about very much. I hate these mantras > "map what's on the ground" and "don't map for the renderer", because > they're apt to be misunderstood and over-applied. But I think > essentially there are few instances where our approaches would lead to > very different outcomes. > >> I know. I'm simply saying that where no such human defined route backed up >> by cycle facilities on the ground exists, we should include the features >> present, not invent a route. > > And I'm slightly more liberal. > >> No doubt it is in the map providers interest to make the route appear >> connected, even when in reality they may not have made a single change to >> the facilities on the ground. However, the reality may be in some case that >> there are actually gaps in the route. I see this very much as an edge case, >> and I can see arguments for including the connecting segments in an official >> named route like this one. > > Cool. > >> Adding physical infrastructure is always useful. It never does any harm. > > Sometimes exhaustively listing every "unofficial" (but "on the > ground") walking track in a park can just create messy confusion. But, > yes, generally. > >> Every bad route we add severely diminishes the value of the good ones, and >> we see this happening already in Sydney. There is a signed cycle route >> heading down Parramatta Rd at Croydon. This is a 3 lane, very narrow laned >> road with heavy vehicles and high traffic volumes. If we mark that in OSM >> in a cycle route, we may as well give the game away. > > Here, I disagree. You obviously have an interpretation of what a bike > route should be (safe, for starters). But I think if the authorities > have decided a bike route goes down a busy road, then we should follow > that. > > If you're seriously arguing against mapping this route, aren't you > contradiction your "map what's on the ground" philosophy? Signs are > "on the ground". > >> I've no idea how you allow unofficial routes to be used in moderation. How >> do you decide which to keep? How do you decide who gets to decide? > > One thing I can say: just because you (or I) don't know the answers to > questions, doesn't mean something is a bad idea. In any cases, the > answers are probably "the community decides, if and when it becomes a > problem". > >> Would OSM really be a better project if we were to do a data import from >> bikely? > > I can't see that going well. > >> Let's be careful with cycle routes in Australia. > > Nah. Compared to organised countries like the UK or Germany, we have > little infrastructure, no wide-scale consistency, and few published > conventions to follow. Until the day comes when there exists something > like the LCN/RCN/NCN system, we're going to have to use liberal > interpretation to achieve a useful result. > >> The cycle facilities are >> sparse compared to the bicycle signs and council routes. There is no >> central coordinating or certifying authority. I'd argue against adding >> personal routes, add the physical information for a router instead. > > Automatic routers are just one audience. Humans are another. Provide > route information for humans, and let the computers ignore it. > > >> This information is far more valuable, and as a project it plays to our > > It's not an either/or situation. > >> strengths. I'd also argue against adding other routes where no cycle >> facilities exist, or the route is dangerous. Particularly where the >> information is source from council maps that aren't recently updated, or >> from bicycle signs that point off a main road or cycleway. > > Right. You'd like to use interpretation and subjectivity as well. > > Steve _______________________________________________ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
