pelderson
commented
3 years ago Width is sometimes important too. The tags I use now are:
vertical_clearance= / height above water level of the lowest obstacle for this route relation. horizontal_clearance= / width of the narrowest point of this route relation. depth= / depth of the shallowest point in this route relation.
All in m, with two decimals. Operators provide the value in cm. Standard OSM handling applies, so 365 cm is valid, 10 m is valid, 10.00 (no unit) is valid. Tagged on the route relation.
The users probably want this information from the viewpoint of the boat: How high can a boat be to complete this route; How wide can a boat be to complete this route; How deep can the boat go to complete this route.
The information is provided by the operator of the network, as "guaranteed height/width/depth". It is seldom mapped on the ways of the relation or on the obstacles encountered, except for the big waterways where any vessel in this category can pass.
I would like to suggest looking into support for tagging of height (vertical clearance) on boat and canoe routes. Same suggestion, but less pressing, for depth.
Boats need depth underneath, and clearance above. Availabe depth can be mapped on the waterways and clearance can be mapped on the waterways (width) and on bridges and other overhanging elements on the nodes and ways representing the obstacle, but this not really done except for large waterways.
For users plannng routes, especially for smaller vessels, clearance and depth are very important. Usually this is given/required as maximum boat heigth (above waterlevel) that a route tolerates, or the "guaranteed passing height" (gegarandeerde doorvaarthoogte). Which is the same as the lowest vertical clearance you can encounter. About the same story goes for the depth.
The wish is to show depth and height information for the node2node routes and for the planned route, comparable to and in addtion to route lengths. In particular the clearance informaton is crucial for motorboats.
A step further would be help with planning. E.g. the line type could show on the map if a route is under or above a certain clearance. Even more helpful would be if the user could set a cut-off value for the session, the planner could then adapt the display and the routing, possiibly even discard routes not guaranteeing this required clearance.