User:Alan Vos/OSM Whitewater Tagging and Rendering
!!! Work in Progress !!!
whitewater=portage
On Highways
To show a portage/inspection route. Rendered as a dashed brown line on top of the underlying highways. Use for any such route, whether mandatory or just used to bypass/inspect a runnable feature. Useful when the route starts well above the feature, is not obvious, portaging should be restricted to the left/right bank etc. Could also be used to highlight a walking route between parking and a get_in or egress
On Waterways
Intended only for 'mandatory' portages (accepting that a few will find a way to run anything) such as:
- physically impassable e.g. a boulder choke
- legally protected e.g. a Site of Special Scientific Interest (SSSI)
- very dangerous and only occasionally run intentionally e.g. Pont Cyfyng on the Llugwy
- closed by local lawmakers with "STOP" signs or otherwise
Where a portage is tagged, any section or rapid grade will still be shown as this can still be useful. Knowing whether the 'portage' a swimmer is about to enter is a grade 3 SSSI or a grade 6 rapid allows for a more informed decision. On some rivers where there is a lot of casual paddling, STOP signs exist on weirs which more experienced paddlers normally run.
On ways a portage is rendered as row of purple diamonds on top of any whitewater:rapid* or whitewater:section* information.
On nodes a portage is rendered as 
with any whitewater:rapid_grade shown on top. The name is taken from the name tag.