There is one cosmetic difference I have noticed. The roundabout junction diagram in the top left of the Garmin screen always reflects the drive-on-left/drive-on-right mode. If I compile a map for the UK without "drive-on-left", the spoken and written routing instructions are correct (so turning right at a roundabout will be "take third exit") but the little icon will reflect taking the roundabout in an anti-clockwise direction. Another reason for using it is for motorway exits. If you have a fork between (for example) two motorway_links you can normally assume (as a heuristic) that the left fork (driving on the left) is the "exit" and the right fork is "straight on". If neither drive-on-left nor drive-on-right is specified, mkgmap uses the first roundabout it encounters to work it out.This COULD go wrong, although it is unlikely. The bounding box for the UK includes bits of France so it may depend on what the splitter puts in the first tile. Just in case it is good to have a way of setting this explicitly. Colin On 12/07/2012 13:33, Frank Fesevur wrote:

2012/7/12 aighes <osm@aighes.de>:

...

what is the advantage of using --drive-on-left? I think routing shouldn't be influenced, because oneway=yes should be obvious and on normal roads/ways there shouldn't be any difference at all. What about roundabouts? Routing a roundabout and saying "first exit" or "third exit" is a major difference.

Don't see much other things though.

Regards, Frank _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev