Re: [talk-au] Traffic Signals
On Fri, Mar 12, 2010 at 8:52 AM, Steve Bennett wrote: > > ... So far, I haven't seen > much evidence that we have ways of aggregating excess information into > more manageable chunks. As others have already suggested: we need relations. There's already proposals semi-underway here: http://wiki.openstreetmap.org/wiki/Relations They need more work, though, so... go for it! ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On Fri, Mar 12, 2010 at 10:21 AM, John Henderson wrote: > Other than de-cluttering (which tends to be done automatically anyway) > I'm not sure why you'd want to render only one set of lights if there > were more than that. Well, because to most people a "set of lights" covers a whole intersection. If there are lights northbound, southbound, eastbound and westbound, that would be one "set of lights" to most people. You could equally ask, why would you want to render 4 sets of lights when there is only one? > In this case, placing the lights accurately in their lane gives the > correct count whereas it's your system which doubles up the number! Heh, you could be right. I think the relation scheme David referred to would be the way to go. > Whether on not an intersection has lights for a particular vehicle often > depends on the exact roure taken through that intersection. To > oversimplify can often be to mislead. Often? Apart from left-turning sliplanes, are there other cases? Steve ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On 12/03/10 09:52, Steve Bennett wrote: > At the cost of managing that extra information. So far, I haven't seen > much evidence that we have ways of aggregating excess information into > more manageable chunks. > > Put it this way: how would you render a single circle for any > intersection that has a traffic light? That is, if there are traffic > light nodes at one intersection, you still only want to render one > circle. It's a pretty obvious use case. Other than de-cluttering (which tends to be done automatically anyway) I'm not sure why you'd want to render only one set of lights if there were more than that. But you could always limit the number to one for any given radius of a crossing or close group of crossings. > How would you count the number of traffic lights along a given route? > The scheme that's been described here would return double the actual > number. Consider divided roads crossing, where you'd presumably put 4 sets of lights on your scheme (at least that's how I inevitably see it being done in OSM). In this case, placing the lights accurately in their lane gives the correct count whereas it's your system which doubles up the number! > I'm not saying extra information isn't sometimes a good thing, but the > task of simplifying that down to a useful set of information isn't > trivial. Why do you think anyone needs to? > Perhaps we want to distinguish between an "intersection with lights" > node and an "actual traffic light" node. Whether on not an intersection has lights for a particular vehicle often depends on the exact roure taken through that intersection. To oversimplify can often be to mislead. John H ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On Fri, Mar 12, 2010 at 9:43 AM, David Murn wrote: >From a routing perspective, its more useful to have the information on > the road intersection. While it might render nicer if you put objects > geographically where they are (separated from the road), from a routing > perspective thats not much use unless you use a relation to relate the > traffic lights to the roadway the traffic lights are on. This is the general tension between a schematic diagram and an accurate representation of the world, which has become more accute since the arrival of Nearmap, where sub-metre accuracy now matters. It also causes the problem with footpaths meeting roads: part of the footpath represents the actual physical location of the footpath, and part is a schematic line showing that it does in fact connect with the road. But no distinction is made. It shows up with bus stops too: the bus stop is not physically part of the road, but schematically is. The only solution I can see is that we end up with some tags that are explicitly schematic rather than geographically accurate, and with some kind of relation between the physical location node and the schematic node Steve ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On Fri, 2010-03-12 at 09:52 +1100, Steve Bennett wrote: > Put it this way: how would you render a single circle for any > intersection that has a traffic light? That is, if there are traffic > light nodes at one intersection, you still only want to render one > circle. It's a pretty obvious use case. > > How would you count the number of traffic lights along a given route? > The scheme that's been described here would return double the actual > number. One thought that has been proposed here before, is adding all traffic lights at an intersection to a relation. That way, you simply count the number of traffic light relation groups along the way rather than the number of nodes. This means if you have two junctions close to each other in distance, but that are physically separate traffic light controls, that youd add each light of each group to 2 different relations. > Perhaps we want to distinguish between an "intersection with lights" > node and an "actual traffic light" node. The problem here, is that if you have an 'intersection with lights' that doesnt necessarily affect all ways going through the intersection. For example, some roads have traffic lights on the slip-lane where others dont, and as I mentioned in my first email, you also have to allow for the crossing=traffic_signals node used between foot/highway intersections. David ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On 12/03/10 09:43, David Murn wrote: > From a routing perspective, its more useful to have the information on > the road intersection. While it might render nicer if you put objects > geographically where they are (separated from the road), from a routing > perspective thats not much use unless you use a relation to relate the > traffic lights to the roadway the traffic lights are on. A good point. But I didn't even think of putting the lights anywhere other than as a node of the appropriate road. John H ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On Fri, Mar 12, 2010 at 9:09 AM, John Henderson wrote: > The benefit is in greater accuracy and completeness. If we can do > better than commercial street directories, then why not? At the cost of managing that extra information. So far, I haven't seen much evidence that we have ways of aggregating excess information into more manageable chunks. > Insisting that everyone do it that way would be a pain. But if the > information is available then I see no problem in my capturing it if > convenient. Nor to I see any pain caused to the user of the more > complete maps. Put it this way: how would you render a single circle for any intersection that has a traffic light? That is, if there are traffic light nodes at one intersection, you still only want to render one circle. It's a pretty obvious use case. How would you count the number of traffic lights along a given route? The scheme that's been described here would return double the actual number. I'm not saying extra information isn't sometimes a good thing, but the task of simplifying that down to a useful set of information isn't trivial. Perhaps we want to distinguish between an "intersection with lights" node and an "actual traffic light" node. Steve ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On Thu, 2010-03-11 at 23:50 +1100, Franc Carter wrote: > Hi, > > I use to tag traffic signals at the intersect of the roads, however > with NearMap I can see that for complex intersections this does not > work as well as I would like, three things I can see to do are:- > > 1. tag at the intersecttion of roads > 2. tag at the location of the signals > 3. either (1) or (2) depending on the complexity of the intersection. > > What's peoples views on this ? >From a routing perspective, its more useful to have the information on the road intersection. While it might render nicer if you put objects geographically where they are (separated from the road), from a routing perspective thats not much use unless you use a relation to relate the traffic lights to the roadway the traffic lights are on. Also, traffic signals arent only used for road intersections, traffic lights are also sometimes used to control pedestrian crossings between a footway/cycleway and a highway, which I feel is useful to tag. David ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On 12/03/10 08:39, Steve Bennett wrote: > On Thu, Mar 11, 2010 at 11:55 PM, Luke Woolley wrote: >> Personally, since NearMap became available, i've been placing traffic light >> tags at every thick white stop line at the intersection, which means for a >> standard intersection, there are 4 traffic light nodes. > > What's the benefit of this rather than, say, one traffic light node on > the centre of the intersection? Is the exact location of the light > itself important? I'm comparing this approach to the Melway, which > uses a big purple circle across the intersection to indicate the > presence of traffic lights, mostly as a landmark I guess. The benefit is in greater accuracy and completeness. If we can do better than commercial street directories, then why not? To my mind, it's a bit like deciding whether to make a minor road with a concrete dividing strip a divided road or just a two-lane, two-way single road. > The extra detail of individual lights might be more of a pain in the > arse than actually useful? Insisting that everyone do it that way would be a pain. But if the information is available then I see no problem in my capturing it if convenient. Nor to I see any pain caused to the user of the more complete maps. And you never know when accurate information might prove useful. John H ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On Thu, Mar 11, 2010 at 11:55 PM, Luke Woolley wrote: > Personally, since NearMap became available, i've been placing traffic light > tags at every thick white stop line at the intersection, which means for a > standard intersection, there are 4 traffic light nodes. What's the benefit of this rather than, say, one traffic light node on the centre of the intersection? Is the exact location of the light itself important? I'm comparing this approach to the Melway, which uses a big purple circle across the intersection to indicate the presence of traffic lights, mostly as a landmark I guess. The extra detail of individual lights might be more of a pain in the arse than actually useful? Steve ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
On 11/03/10 23:55, Luke Woolley wrote: > Personally, since NearMap became available, i've been placing traffic light > tags at every thick white stop line at the intersection, which means for a > standard intersection, there are 4 traffic light nodes. This is exactly what I've been doing too, although the intersections I've done this way are all ones I'm familiar with. John H ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Traffic Signals
Personally, since NearMap became available, i've been placing traffic light tags at every thick white stop line at the intersection, which means for a standard intersection, there are 4 traffic light nodes. On 11/03/2010, at 11:50 PM, Franc Carter wrote: > Hi, > > I use to tag traffic signals at the intersect of the roads, however > with NearMap I can see that for complex intersections this does not > work as well as I would like, three things I can see to do are:- > > 1. tag at the intersecttion of roads > 2. tag at the location of the signals > 3. either (1) or (2) depending on the complexity of the intersection. > > What's peoples views on this ? > > thanks > > -- > Franc > > ___ > Talk-au mailing list > Talk-au@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-au ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
[talk-au] Traffic Signals
Hi, I use to tag traffic signals at the intersect of the roads, however with NearMap I can see that for complex intersections this does not work as well as I would like, three things I can see to do are:- 1. tag at the intersecttion of roads 2. tag at the location of the signals 3. either (1) or (2) depending on the complexity of the intersection. What's peoples views on this ? thanks -- Franc ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
