[PATCH] Warn about unconnected highway=milestone

[naoliv]

​https://wiki.openstreetmap.org/wiki/Tag:highway=milestone says that the node should be part of the way that represents the highway.

Patch bellow adds a test for unconnected highway=milestone:

data/validator/geometry.mapcss

@@ -216 +216 @@
 node:unconnected:in-downloaded-area[highway=give_way],
 node:unconnected:in-downloaded-area[highway=traffic_signals],
 node:unconnected:in-downloaded-area[highway=crossing],
+node:unconnected:in-downloaded-area[highway=milestone],
 node:unconnected:in-downloaded-area[crossing],
 node:unconnected:in-downloaded-area[railway=crossing],
 node:unconnected:in-downloaded-area[railway=level_crossing],

(a more complete test would be if the node is connected to a highway=*)

[Klumbumbus]

Hm. without reading the wiki page intuitively I would have placed the node at the milstones real position similar to traffic signs. There is a comment on the discussion page too ​https://wiki.openstreetmap.org/wiki/Talk:Tag:highway%3Dmilestone#Node_on_the_way_or_in_the_mark_position.3F

[naoliv]

If we don't use the node connected to the highway and if we have two or more nearby highways, then we won't be able tell which highway it belongs to; ​https://wiki.openstreetmap.org/wiki/Key:traffic_sign#As_a_separate_node also says:

it is impossible to reliably deduce the affected road or travel direction in this case

From what I see it makes more sense to have it connected to the highway.

[Klumbumbus]

In 13074/josm:

fix #15478 - Warn about unconnected highway=milestone and railway=milestone (patch by naoliv)

[yellowsoar]

I think this rule need more discussion...
And the sentence was added without refs so far:
"The node should be part of the way that represents the highway."
​https://wiki.openstreetmap.org/w/index.php?title=Tag%3Ahighway%3Dmilestone&type=revision&diff=1493715&oldid=1437923
FYI, there's a discussion in OSM.TW about this:
​https://www.facebook.com/groups/OpenStreetMap.TW/permalink/1646759588722837/