On Sat, Mar 15, 2014 at 06:12:10PM +0000, moltonel 3x Combo wrote: > On 15/03/2014, Fernando Trebien <[email protected]> wrote: > > I now agree that the "layer" tag should be used as locally as > > possible, so I think Richard had good intentions when proposing this. > > At the same time, I think you, Frederik, has a good point that > > arriving at a threshold for that number is quite hard. What exactly do > > we want to avoid? Really, really long ways with a layer tag. So why > > not set this threshold higher? Say 10 km? > > Validator rules are a good thing, but I think that "length of a way > that has layer=*" to detect misuse of the layer tag is beside the > point. Whatever threshold you use, there'll false-positives and > false-negatives. How about something along the lines of "negative > layer but no tunnel tag (or positive/bridge) and no/too many crossing > ways" ?
I am now thinking about "unless absolutely necessary the size of objects tagged with a layer tag should not exceed a size which would be typically downloaded for editing in this area." but the wiki page already says << * Tag shortest possible/practical sections of ways. Long viaducts and tunnels can be tagged with a suitable single value for their entire length for simplicity although it may sometimes be better to adjust the layer along its length to accommodate more complicated crossings. * Use the smallest suitable layer value. Only use layer=2 for a bridge that passes over a feature that is already at level 1; similarly only use layer=-2 for a tunnel that passes below another tunnel. For convenience some higher values are often locally used/reserved for very long bridges or underground networks where it is assumed that they are above/bellow most other crossings/objects in the area. >> - which should be good enough if people don't interpret the text in some unforseen way. Richard _______________________________________________ talk mailing list [email protected] https://lists.openstreetmap.org/listinfo/talk
