2009/5/21 Teemu Koskinen <teemu.koski...@mbnet.fi>: > On Thu, 21 May 2009 03:13:06 +0300, Radomir Cernoch > <radomir.cern...@gmail.com> wrote: >> We are seeking a situation, where two large areas with road networks >> overlap each other on a map. All streets in one area must have a >> different speed limit from streets in the second area. In such a >> situation, using "maxspeed=*" tag on any street must be inappropriate. > > http://openstreetmap.org/?lat=60.18933&lon=24.9642&zoom=18&layers=B000FTF > Sturenkatu is in 40 km/h zone, the zone continues over the bridge. > Teollisuuskatu is in 50 km/h zone that is signed with the city sign. > > Both zones also include large amount of other roads. IIRC the 50 km/h zone > can be followed from that point many kilometers, and the 40 km/h zone > extends tens of roads. There also might be other overlaps between them, or > with other zones.
Hi, I think this might the point, where the confusion comes from. I do not think that streets like Sturenkatu or Teollisuuskatu, nor any of connected primary/secondary/tertiary form a "zone". I would suggest to define a "zone" as an "area with predominantly uniform traffic regulations". I've spent only a few minutes looking at the map, so here's just a rough idea how such area could be mapped: I would suggest to use "zone-50" for whole Helsinki, because it's the speed limit in Finland for all cities. Smaller areas to south and east from the bridge can be covered by "zone-30". I have seen many 40 km/h streets more to north, which could form "zone-40". These two zones can be easily connected to the large "zone-50" using a multipolygon, because they are inside the Helsinki traffic regulation. However there is no reason for "zone-40" and "zone-30" to overlap. And the roads: If the eg. Hämeentie falls between above mentioned "zone-30" and "zone-40", it will not have to include any "maxspeed=*" tag. Otherwise, it can have "maxspeed=50". I would also like to point out that a map, where all roads have "maxspeed" tag do not have to change at all in order to comply to the proposed schema. Lastly please notice one detail, which proves why I think that zone-polygons are a good idea: If you look north-east from the bridge, there are a few 'service' roads (Allotriankuja, Rialtonkuja and unnamed 5074030). These roads do not have any "maxspeed" tag. Is then their speed limit 100 km/h, which is the limit for paved provincial roads in Finland? Or how do you conclude that these streets are in a city? This example shows that even in a very complete and well made map (like the map of Helsinky), people tend to forget about specifying speed limits. Zone-polygon solves such issues. Best regards, Radek Černoch _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
