Coming back to the lanes-example:
The turn:lanes tag is there to show what direction a lane turns (or,
akin to "map what's on the ground" principle: what arrows are drawn on
the road).
Say you have a junction in the motorway where three lanes continue and
two lanes turn off. I have seen situations where this is drawn on the
road with (from the left) two lanes with no arrows, one lane with a
straight arrow, then a block line, then two lanes with a right arrow.
This could be mapped as:
turn:lanes=none|none|through|right|right
The difference with
turn:lanes=||through|right|right
is that in the first example it is made explicit that there are NO
arrows on the leftmost two lanes.
With maxspeed in OSMAND: if I drive on a way with no maxspeed, the
maxspeed icon disappears, while driving on a German motorway, the
maxspeed icon actually reads "none". (Sadly, my car can only go 125 km/h)
On 24-01-16 11:12, Gerd Petermann wrote:
I don't think so. Where do we need null values in OSM?
As you said, maxspeed=none means something like maxspeed=unlimited.
I can't think of any tag key which should be stored in OSM with a null
value.
In what case would that add valud information compared to having no such
tag ?
Gerd
------------------------------------------------------------------------
*Von:* Colin Smale <colin.sm...@xs4all.nl>
*Gesendet:* Sonntag, 24. Januar 2016 10:58
*An:* Tag discussion, strategy and related tools; Tijmen Stam
*Betreff:* Re: [Tagging] Removing name_1 and alt_name_1 from Wiki
At present the string "none" is actually a value, the interpretation of
which is specific to the key "maxspeed" . Maybe we should promote it to
the equivalent of NULL in SQL.
On 24 January 2016 10:43:16 CET, Tijmen Stam <mailingli...@iivq.net> wrote:
With the value "none"
For example on German Autobahnen, where you can drive as fast as you
want is "maxspeed=none" which is different from having maxspeed not set:
this means maxspeed is unknown or not tagged yet.
On 20-01-16 09:06, Colin Smale wrote:
Exactly.
If a missing value (i.e. use the default) is not the same as
explicitly
having NO value, how do you override the default with "no value"?
--colin
_______________________________________________
Tagging mailing list
Tagging@openstreetmap.org
https://lists.openstreetmap.org/listinfo/tagging
