Is there a standard (or common) way to indicate whether a river is navigable? Even better, are there standard ways of showing various grades of navigability (accessible to small craft only, accessible to deep water vessels, etc.)?
Roads tend to be well marked to show their usefulness, from dirt trails to paved multilane highways. I'm doing a project where it would be very handy to indicate the usability of rivers and creeks as well. I could make up some indicators, but I'd prefer to follow existing models if possible.
I'm looking for a software-agnostic answer.