[mkgmap-dev] motorway_link not always oneway

Tue Oct 26 18:01:36 BST 2010

On 10/26/2010 06:17 PM, Torsten Leistikow wrote:
> I checked some examples in Germany:
> Here it is quite normal, that part of the motorway_links have to lanes, one for
> each direction. These are either mapped as two separated lines (but mostly they
> are not separated, so imho this is actually a mapping error), or they are mapped
> as one single line, but normally without any oneway attribute.

Motorway_link implies oneway=yes according to wiki 
(http://wiki.openstreetmap.org/wiki/Motorway_link)

In case it is not oneway=yes it is a mapping error not to tag it 
oneway=no. However, I see that this is a very easy mistake to make!

> - If we do not assume oneway=yes and our assumption is wrong, the the routing
> might give some false turn commands (in most cases this will not happen, since
> the allowed way is also mostly the fastest way), but will always use the nearest
> junction.
>
> As a consequence, I think we shouldn't assume one=yes as default for motorway_links.

That would work mostly well I guess. However, it is better to fix 
mapping errors than try to adjust style for correcting them.
--
Harri