[OSM-talk] proposal: relation type=way_affected ("on the beginning of the street")

[Stanislav Brabec]

Rory McCann wrote:
> On 06/11/08 08:27, Stanislav Brabec wrote:
> > 
> > "Just on the beginning of the private way" is one of the common places
> > for barriers. Its mapping makes an apparent clash between reality and
> > mapping schematic - there is no way to mark this fact exactly.
> > http://www.openstreetmap.org/?lat=50.071094&lon=14.425607&zoom=18&layers=B000FFF
> > 
> > You cannot draw the barrier just on the cross node - the main street has
> > no gate, it's only on the private way. Drawing it on an additional node
> > gives a bad assumption, that one should search a way with a gate say
> > 10-20 meters from the cross. In fact one should search a gate just next
> > to the street, with no part of the private way visible. Some renderers
> > even render the barrier incorrectly inside the main street line.
> 
> I know what sort of feature you're talking about. But I would have
> thought that the barrier (or whatever) would be ever so slightly on the
> private way (eg 10cm in). Would it not make more sense to have a node
> veeeeeery close to the start of the private way?

It would be OK, if OSM would exactly map the world, centimeter by
centimeter.

But the way is only a schematic one-dimensional object, so we also need
a schematic method to mark "just next to the way".

Renderers have no idea about exact way width and attempt to render the
barrier inside the schematic line of the main way (exactly on the place
"veeeeeery close to the start of the private way").


________________________________________________________________________
Stanislav Brabec
http://www.penguin.cz/~utx