On 01/12/2010 07:08 PM, Ross Scanlon wrote: > Likewise don't put roads that are on the same pavement on different layers > it's not mapping what's on the ground.
OK, I have re-read the layers tag on the map features page and it says "This is intended to indicate actual physical separation, shouldn't be used just to influence rendering order." I thus conclude that using layers is the wrong approach. We now have 4 possible ways to map and in all cases crossing ways have a common node. 1> use no restrictions and assume oblique angle turns will not be made. 2> use highly schematic representations. 3> break ways at every node with appropriate turn restriction. 4> turning lane is an only_straight_on via in the relation. On 01/12/2010 07:07 PM, John Smith wrote: > 2010/1/12 Roy Rankin<rran...@ihug.com.au>: >> The example I gave was a simplification to demonstrate the issues. From >> Johns response I did realize I had gotten the directions which I assumed >> is why it did not make sense to him. If you want to visualize the >> situation look at the link I supplied >> (http://www.openstreetmap.org/?lat=-33.82907&lon=151.21494&zoom=17&layers=0B00FTF >> ) and consider east bound traffic on Falcon Street turning right to go > > Only a couple of common sense things, cars normally don't make turns> > 90 degrees, so you generally don't need turning restirctions in this > cases. My experience of many years with both people and computers is that people often show that common sense is not that common and that computers have none at all. It may be just a fringe case, but I believe that if a turn is not prohibited then sooner or later a route will be drawn the uses the turn even if it does not make sense. > > Secondly, I don't think it looks legal for cars to go straight if they > are coming off the motorway as is the case with way IDs #47063022 and > #47063028, the arrows indicate turning only. I did not map this and my first reaction was similar to yours. When I looked more closely the arrows have buses excepted and the straight on way is tagged as psv=yes. There is also a dashed line to guide the buses to rejoin the motorway. > > Simply setting most of those turns to be one way will be sufficient > for routing (and humans for that matter) to figure it out. I do not believe this attitude will result in the best routing experience possible. _______________________________________________ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
