[OSM-talk] Turn left restriction on two way highways

Eugene Alvin Villar seav80 at gmail.com
Fri Dec 31 07:51:05 GMT 2010


On Fri, Dec 31, 2010 at 3:25 PM, Hendrik Oesterlin
<hendrikmail2002 at yahoo.de> wrote:
> "Eugene Alvin Villar" seav80 at gmail.com wrote on 31/12/2010 at 13:11:26 +1100
> subject "[OSM-talk] Turn left restriction on two way highways" :
>
>
>> I remember a suggestion like this a long time ago. Tagging a way with
>> restriction=no_left_turn (especially if it has a oneway=yes tag) would
>> specify a default for that particular way only. This is much easier
>> for routers or preprocessors to adopt.
>
> But today it is not supported by any routing engine I know of.
> Even the Garmin file format created by the mkgmap tool cant't handle
> this today.

Not currently, but preprocessors such as mkgmap can adopt this. Garmin
routers themselves have *no* conception of turn restriction relations
as they exist in OSM--it is mkgmap that translates these turn
restrictions into the format that Garmin understands. So it should be
just an additional code in mkgmap to support restriction=no_left_turn
tags on ways.



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