[Tagging] How to tag small canals?

[Christoph Hormann]

On Saturday 18 August 2018, Peter Elderson wrote:
> Sure. But is there a standard method to indicate this uncertainty in
> OSM, which can be processed by data consumers?

This is outside the scope of of OSM IMO and not practical for mappers to 
determine in a meaningful way.  You can specify the method used to 
determine the width (using source:width=*) and different methods will 
have different inherent measurement accuracies but the accuracy of the 
values depends on lots of other factors beyond that.

Practically mappers have usually no way to verifiably determine the 
accuracy of their measurements unless they have a reference value of 
known high accuracy in which case the whole excercise is pointless.  
Theoretically mappers could practice their measurement skills and 
assess their personal measurement accuracy based on test measuring a 
statistically significant number of cases under comparable 
circumstances with a known accurate reference value but practically 
this is not feasible.

-- 
Christoph Hormann
http://www.imagico.de/