[OSM-talk] Ditches

[John Smith]

2009/12/15 Steve Bennett <stevagewp at gmail.com>:
> On Tue, Dec 15, 2009 at 2:36 PM, John Smith <deltafoxtrot256 at gmail.com> wrote:
>> I tend to mark bridges as layer=1 and anything at ground level I don't
>> set a layer tag, which seems the most logical to me since ditches
>> aren't under the ground etc.
>
> The one benefit of marking waterways layer=-1 (particularly for long
> ones) is that it's protection against anyone else forgetting to set
> layer=1. That is, someone else might draw a bridge over it somewhere
> and not set the layer. Well, if the waterway itself is -1, that will
> still behave the same.

Except keep right and other validators will complain and let you know
you've forgotten.