[mkgmap-dev] motorway_link not always oneway

Tue Oct 26 16:17:50 BST 2010

maning sambale schrieb am 26.10.2010 10:53:
> The default style treats motorway_link as oneway by default. I've seen
> some cases (in the Philippines) where this isn't so.  Is it the same
> case for other countries? If so, I propose we modify the default
> style. Or, any suggestions to modify the style?

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.

What happens in case our default assumption is wrong?
- If we assume oneway=yes as default and our assumption is wrong, then some
motorway junctions are not usable at all for the routing (either for leaving or
for entering the motorway). So the user will be routed to another junction
further away.

- 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.

Gruss
Torsten