On 01/12/2011 05:07 PM, ant wrote:
A node in this context means "a place where i can change from one bus (tram) line to another without having to walk more than a few metres".In the proposed scheme a stop area is exactly this.
Sorry, but this is absolutely pointless. First of all, modern routing software can calculate a route finding the nodes from stops' coordinates (Hafas and Google Transit). It will consider two stops to be a node if a distance between them is lower than a certain constant. So those can be created dynamically, humans are not necessary. For speed, popular pairs of stops are stored in a static table.
Secondly, if you insist on "stop area", then you create a weak point for the routing program, because it would rely on human input creating those areas. One area missing, and the entire routing algorithm goes to hell, because the program would send you through another "stop area". Such errors would be very visible, and the users would be disappointed. Who wants to be taken for a ride all over the town because of one missing "stop area"?
I mean no offence, but please understand that this is the 21st century. Your suggestions are indeed correct, but are applicable to software standards that were there 10 or 15 years ago. Much more can be done now.
Point: Leave it to the algorithm instead of asking humans to do it.
So the point of stop area relations is to prepare the data to be interpreted as a network and thus to make routing... easy.
Programs such as Hafas are some years of age, and already they do it easier than you propose. They do it the way I described above: finding connections by distance between stops, and calculating the "price" to walk. A connection with a shorter walk is of course preferred, as is a connection without transfers.
Greetings, LMB _______________________________________________ Talk-transit mailing list Talk-transit@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-transit
