[OSM-dev] osm2pgsql, direction of a virtual way (based on a route)

Andy Allan gravitystorm at gmail.com
Wed Oct 26 18:36:56 BST 2011


On Wed, Oct 26, 2011 at 5:47 PM, Frederik Ramm <frederik at remote.org> wrote:

> "this way has to be reversed to form a linestring with the others",

more like "the direction of the route is with/against the direction of
the underlying way"

> while
> others seem to use "backward" as "the bus only uses this section of road on
> the return journey".

Which is, and always has been, completely stupid.

> But I have not systematically looked into this. Someone should perhaps do
> that. - Most route relations are probably not directional (cycle routes come
> to mind).

Bear in mind that cycle routes are one of the earliest and heaviest
users of forward/backward roles. It is easy to find them on
opencyclemap, e.g. at

http://osm.org/go/euu4OUOi?layers=C

I'm disappointed to see that whoever came up with the new PT schema
didn't understand what these roles are useful for, which was nothing
to do with the overall route characteristics (towards or away from one
particular place), instead they are for expressing the relation
between the direction of travel and the direction of the way. The
separation of every bus routes into two bus routes, one for each
direction, even when they are simply duplications of one another, is
surely a waste of time and effort.

Cheers,
Andy



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