On 2015-06-17 15:08, Michał Brzozowski wrote:
On Wed, Jun 17, 2015 at 2:55 PM, Eugene Alvin Villar <sea...@gmail.com>
wrote:
Imagine a single-carriageway road crossing a dual-carriageway road.
All turns are allowed except u-turns from one side of the
dual-carriageway to the other. This common situation can only be
modeled using a turn restriction with a via way.
Now if the via way had to be split for any reason, then you have
multiple via ways.
Isn't the restriction type (no_u_turn, no_left_turn, no_right_turn)
basically just for display purposes? Because given from, to and via it
only matters whether it's no_* or only_*.
The solution I think is going to give correct routing would be to make
a no_u_turn where one of the carriageways is from, the node at
intersection is via and that small connecting segment is to.
No, because then you also restrict left (or right, in LHD countries)
turns.
Imagine this situation (ASCII art):
+------6------8------1------+
|
2
|
+------5------9------3------+
|
4
|
+
Driving from way 1 to way 3 is not allowed (U-turn). Making a turn
restricting from way 1 to way 2 via node 8 prohibits driving from way 1
to way 4 also. You have to make a restriction from way 1 to way 3 via
way 2.
I think you are right in saying that the type of restriction is only for
display and has no real purpose for the router.
Maarten
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