On Mon, Mar 21, 2011 at 5:45 PM, Robin Paulson <robin.paul...@gmail.com> wrote: > i've recently been doing some mapping around auckland, adding coastal > walkways. one in particular i walked on sunday has two routes: one at > the foot of the cliffs, one on the road at the top of the cliffs. the > lower route is under water when the tide is in, so walkers are advised > to follow the road route. > > so, i added the route, and it is now under water: > http://www.openstreetmap.org/?lat=-36.927322&lon=174.709115&zoom=18&layers=M > > this seems wrong, drawing a route which is then under water, but the > alternative of moving the path is also wrong. > > so, what do we do? > > the question becomes (in my mind): why do we have a single way mapped > 'coastline'? this implies the boundary between land and water is > static, but of course it moves - a number of times per day. > > i like the possibility of a high water mark and a low water mark, used > together to entirely replace the natural=coastline tag. > > perhaps some of you have some ideas around this also?
I don't have a solution but I certainly admire the problem. To complicate things, while maps may show mean high-water, borders seem to be mean low-water. WIkipedia says so. Adjusting a coastline polygon based on aerial imagery will get us something in between. Or something not-between because mean high-water is a mean. So that's all really bad and difficult to map. How about extending intermittent=yes from rivers and streams to footways as well? It would take an advanced router to know to look for intermittent=yes to avoid that path for the walker less likely to check conditions for themselves. Perhaps highway:intermittent=footway so that the intermittent footway fails to be found by tools that aren't aware footways can be intermittent? _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk