[Tagging] simple_brunnel : one node bridge like xing highway over waterway

[Richard Z.]

On Wed, Apr 02, 2014 at 07:44:40PM +0200, Tobias Knerr wrote:
> On 02.04.2014 18:14, Richard Z. wrote:
> > On Wed, Apr 02, 2014 at 05:59:40PM +0200, Martin Koppenhoefer wrote:
> >> IMHO there is a fundamental problem to your proposal because you want to
> >> connect 2 ways with a node which are in reality disjunct 
> > 
> > objects connected with pylons and lifts are also disjunct. So what?
> 
> Don't dismiss that argument so casually. The current rule is that the
> way below the bridge should not share a node with the bridge itself.

the current idea that culverts float bellow roads without having anything
common with them is not correct in most cases. These culverts are part of 
an integral highway-culvert-waterway construction. The same is true for 
most bridges, only a small fraction does float independently above valeys 
but most are connected with the lower way by the actual bridge construction.

> I could imagine adding an exception to that rule if it were hard to
> avoid a shared node. But in this case, it can very easily be avoided by
> mapping the bridge in the same manner two million other bridges have
> already been added: as a way.

easily? So you have biked 60 miles along a forest track and know reliably 
that there was not a single ford on your route today. You look at OSM data 
in the evening and see there are 120 streams which you crossed with missing
bridges/culverts. 

What do you do? Leave those 120 crossings in incomplete state even though
someone might be really interested to know whether there are some fords on
the way?

Add fictional bridges or culverts?

Say "ford=no"?

The other point - even if you know it is a bridge or culvert - is it worth
"painting" an insignificant structure which is perhaps 3m in size when the 
GPS error is more likely 10 meters? In a deep valley and forest in the mountains
you are often lucky to get GPS precision better than 60m.

Richard