Sven Grüner wrote: > Many sluices I know from France, Germany and Scotland have small tags > (or even carved stone) stating the height above sealevel or at least > their level-difference. You can then go and tag the nodes in the > waterway right next to the lock and give them ele-tags, according to > level-difference. If I understand this correctly is absolute height > (accuracy) of secondary importance.
The important value is the difference, not the absolute height. But we can't use ele, because very often the absolute height (which ele represents) is not available, or at least not better than GPS height accuracy. >> - Locks have a maximum width and length, universally measured in feet. >> It should be possible to indicate what it is, presumably using maxlength >> and maxwidth. Is there a danger of these being rendered with symbols >> appropriate only for roads? > > Speaking for my own: I don't see why this should cause interference with > roads. That must be a dumb routing-algorithm sending cars over canals > because of such a tag :-) No, I mean if the symbol on a map for a maxwidth restriction is a red circle with a white inside (i.e. a road sign), you might get them on canals. Perhaps not worth worrying about. > But please keep in mind that distances and height in OSM are generally > saved in meters, not in feet. If the british boaters are used to feet > the renderer would need to convert for their charts. If metres are the standard, we'll have to use metres and canal map renderers will convert. >> - It is useful to denote the rise/fall of a lock (again, universally >> measured in feet). There needs to be a tag for this. We could >> appropriate "depth", but it's not actually the depth of the canal. > > Is this the same as level-difference? I'm a landlubber... Yes. > We have the ref-tag to store all kinds of IDs. There are extensions like > int_ref, nat_ref and loc_ref or ncn_ref and so on to tell to which > network the id belongs. Mybe it would make sense to invent something > like canal_ref or some kind of abreviation. Great idea. canal_bridge_ref. > If you make separate ways for each bank that should suffice. You don't make separate ways for each side of most roads; so it doesn't make sense to me for the standard way to map canals to be one way for each side of the canal. Gerv _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
