Hi Paul, How do passengers know where to go and stand if there are no physical markers? I think a bus stop should be able to be defined by the fact the driver knows where to halt and the passengers know where to wait. Isn't that 'convention' also some sort of ground truth? I"m sure this case happens in many countries around the world, although in some of those countries it may be the case a bus can be flagged at any point on its itinerary. Of course, as soon as roads become busier, that's not possible/practical anymore.
I've been working a few years adding almost 70000 stops for a small country. That was a lot of work, of course. But now I notice that adding and maintaining the routes is even more work, hence the creation of the script to automate the process where possible. One of the problems I faced is that when I needed to fix a route, I had to apply the same fix to all the variations of that route, over and over again. Now I do it once, creating a 'golden route', then letting the script take care of the others. It's still some work, as I need to check manually if the code got it right, route by route. Concerning the roles, I guess they may help JOSM and iD when people split ways, although I think JOSM gets that right without them already. A bigger problem is people joining ways, which results in stumps that are not connected to the next way anymore. And of course, deleting ways, potentially replacing them by new ones. Jo 2015-02-22 6:10 GMT+01:00 Paul Johnson <ba...@ursamundi.org>: > On Sat, Feb 21, 2015 at 3:48 PM, Jo <winfi...@gmail.com> wrote: > >> Hi Paul, >> >> I see what you mean now. I dropped the forward/backward roles on the ways >> a few years ago. Recently I thought that they should be a help for the >> sorting algorithm, but your example proves they aren't. >> > > Well, they do help for sorting out which way a route should be going and > in which order to some extent. Though I'm starting to wish we had a way to > number the sequence. Role wouldn't do it since we still need forward and > backwards... > > >> I've been developing a script, which tries to use other good relations to >> fix the one it's currently run on. >> >> For that script to be able to work, you'd need the stops in the correct >> order though. >> >> It works like this: >> >> For a sequence of stops it tries to find other relations which have the >> same sequence. The other relation with the longest sequence in common >> 'wins'. >> >> Then it finds the ways adjacent to the stops on each end of the sequence, >> then uses the sequence of ways that connects the stops. >> >> We can work that way, because we have received the stops and the >> timetables from the operators, but it's the opposite of what you start >> with, when you have to get on the >> bus to create a GPX to get an idea about one the variation routes of a >> line. (After that you'd use the unstable plugin to add the stops that are >> already mapped). >> > > Well, the GPX would gather the itinerary. I still need to go back through > and doublecheck about 1600 stops, since there's a very high number of stops > that aren't signed in any way, shape or form that Code for America Tulsa > received from Tulsa Transit. And, as far as I'm aware, we expect some kind > of permanently fixed marker recognizable as such to be able to map it as a > bus stop. If we *do* have some way to tag this situation despite a lack > of ground truth in the physical sense, then, by all means, someone please > let me know now, so I can back out of tagging stops for a minute, revert > and repull. In which case, I'll have the opposite problem I do now, which > would be *adding* a large number of stops that *aren't* in the data we > got from Tulsa Transit (which, IMO, is the less worse problem to have, even > though that's a bigger project). > > The script works quite well, as long as you have some 'golden' routes it >> can grab way sequences from. >> > > Ouch! Yeah, I'm not entirely sure that's going to be readily done given > Tulsa's situation. I wish this situation were unique, but I somehow think > I'm going to be beating my head against the wall when I start working with > the OK Coders to pull in Oklahoma City's transit systems. And maybe in the > future, the Iowa Pacific Railroad's upcoming regional transit system, the > Eastern Flyer Express and it's associated bus network... >
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