[Tagging] layer=-1, rivers, bridges and tunnels

[fly]

On 14.03.2014 16:36, Pieren wrote:
> On Fri, Mar 14, 2014 at 4:15 PM, Jaakko Helleranta.com <jaakko at helleranta.com>
> 
>> At least OsmAnd renders all waterways with layer=-1 with
>> dashed casing, as if they were underground, which to me makes sense
> 
> That's clearly a bug. Waterways underground is specified by "tunnel=*"
> 
>> So, again : why tag things with with layer= tag when they are essentially on
>> ground level = not above or below other data (or at least natural objects
>> that might be mapped one day *) ? Am I missing something here?
> 
> Real case from real world : a deep ditch where the stream is not
> "underground" but below the "ground" level, is crossing a village
> where we have 10 bridges. Either you add 10 times "layer=1" on the
> bridges or you add 1 time "layer=-1" on the stream.

Well, I do not get your problem, as bridge/tunnel always need a layer
tag and you already have to cut the ways to tag the bridge/tunnel, why
not simply add the layer to the bridge/tunnel and leave everything else
untouched ?

Using layer tags on long ways is discouraged as you often only need it
on a small part and it makes it more difficult as you always have to
check the layer tag of these long ways before adding a new bridge/tunnel
with appropriate layer value.

cu
fly