On Thu, Apr 26, 2012 at 11:19 AM, Ian Sergeant <inas66+...@gmail.com> wrote: > I disagree. The "map what's on the ground" is a good mantra. It > solves 90% plus of contentious mapping issues, by making a decision > to map what is there. It also guides us towards verifiability - which > is a key tenet of any shared piece of work. If you can't verify it, > then ultimately we can't map it cooperatively.
Verifiability and objectivity are the principles here - so let's call them that. "Map what's on the ground" fails in plenty of cases: - walking/bike routes (what's "on the ground" is a few signposts, nothing more) - ferry routes (nothing) - many names, like business names, parks, mountains, etc - administrative boundaries - ski runs (minimal signage, and very hard to distinguish without supporting evidence) - abandoned railways - and, if we're being pedantic, tunnels, bridges, overhead cables, etc etc. It's a marginally useful rule of thumb that quickly breaks down in any serious discussion. Don't overuse it. > Cycle routes are tricky, and we haven't got there yet. Ask three > different road routing algorithms the for a best route, and expect > similar answers. With cycle routes, that won't be the case, and many > different factors need to go into the weighting, and isolating the > routing factors and their weighting is developing. You're talking about something different. There's a difference between a pre-defined "cycle route", chosen by humans and backed up by some kind of signage, website, publication or whatever, and a dynamic, computed route between two places. > > And in my opinion the solution to this is to cling to "Map What Is On > The Ground". If there is a cycle facility there, shoulder space, > shared lane, reduced speed limit, paved cut-thru - these are all > things that will help me get from A to B safely. Unfortunately, just > being on a RMS or council approved cycle route won't. Often roads > that are the most suited for cycling aren't on an "official" cycle > route, just because they don't connect two destinations. Other > linking sections are included on cycle routes even though they are > dangerous for cyclists. > > In this case, there is a user identified safe route connecting two > cycleways, that is different to the council proposed route, and the > proposed council route has no useful facilities. I'd be using the Map > What Is On The Ground mantra here. I wouldn't map the possibly > proposed council route with no facilities. What is the point of that? To help people visualise a complete path from A to B to C to D, even if the "B to C" bit is indistinguishable from any other road "on the ground". For example, see this diversion from the Great Southern Rail Trail onto the South Gippsland Highway here: http://osm.org/go/uGumFQcy-?layers=C Let's say for the sake of argument that there is no bike lane, no signage, and the road is a busy one. It's still clearly correct to indicate the route along that road, because that's where the published route (http://railtrails.org.au/index.php?option=com_railtrails&view=trail&id=144&Itemid=15) goes. > I'd be mapping the facilities that make the safe route a good cycle > route. I'd then be testing out different cycle routers to ensure that > in their "safe route mode", they recommend the best route. > > If they don't, I'd be investigating why, and seeing whether the > problem lies with the tagging, the routing engine, of the route > itself, and making the appropriate suggestions for changes. Many > times I've done this, and actually found a better route than the one I > was using before. OSM is like that. Well, as we all know, everyone maps in different ways. I'd suggest that any and all of these things are potentially worth mapping: - physical infrastructure (bike lanes, bike paths, wide shoulders...) - signed routes - published official routes - published official planned routes - published unofficial routes (in moderation) It depends on the local circumstances, the likely audience, the inclinations of the mapper (and their time availability) and lots of other things. Steve _______________________________________________ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
