Oops, I meant a east bound lane(s) going south crossing the west bound lane(s).
On 01/11/2010 09:44 PM, Roy Rankin wrote: > With the resolution and newness of Nearmap images Freeway/Motorway > interchanges are being mapped in detail rather than schematically. This > brings up the issue on how to best do this. > > Picture this case. A freeway goes north-south and a dual lane east-west > road goes over the freeway with a connection to the freeway. West bound > traffic on the road going onto the freeway heading south must cross the > east bound traffic on the road. Both these ways are oneway. > > I see two possible ways to map the lane(s) turning south and the lane(s) > going east. > > 1> The ways cross with a common node and a no_right_turn or > only_straight_on restriction. (both lane(s) must be broken into two ways > at the common node as required by relations) > 2> The ways cross without a common node but are on different layers. > (Although physically using the same pavement where they cross). With > freeway over/under road and 4 on/off ramps, 4 layers are required. > > To me the second method is the simplest although I usually think of > different layers as having different elevations. > > The reason for this e-mail is I see no discussion of this in the OSM > documentation, but OSM will be easier to maintain if similar situations > tend to be mapped in similar ways. The following anecdote describes my > experience today. > > Today I came across some issues with the turn restrictions on the > interchange between Falcon Street and the Gore Freeway in North Sydney. > > (http://www.openstreetmap.org/?lat=-33.82907&lon=151.21494&zoom=17&layers=0B00FTF > ) The mapper did not realise that ways with turn restrictions must break > at the via node. Unfortunately the current tested JOSM does not handle > turn restriction relations properly when a way is split and much effort > is required to fix up the relations after a way split. As each way had > quite a few turn restrictions I realized that after splitting the ways > it would require some time to sort out the relations. I thus used method > 2 above and deleted all the relations. > > Regards, > Roy Rankin > > _______________________________________________ > 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