Hierarchical Waterway Relation View
This check creates listings of all waterway relations.
The waterways are listet in hierarchical order. One tree of such a waterway list is a watershed.
This lists can be used to track connection errors, too. While fixing some missing connections,
I've seen different reasons, why two waterway relations are not connected:
- incomplete relations: not all way elements are part of the relation
- waterway connected to riverbank: the waterway of the tributary ended at the riverbank and not on the next waterway way
- missing waterway tags on the relation members: In france some boundaries ways are part of the waterway relations but don't have a waterway tag.
- Connection outside the area: The area of the analyses is currently limited to single countries. If riveres flow together outside that area the connection can not be detected.
- Short canals without relations connect larger rivers
- missing waterways
countries
Currently only a few countries have many waterway relations. Here are the links to the results.
technical background
The current implementation is just a small python script that is driven by a config file.
In the config file the waterways are defined that flow into an ocean or a see. (e.g. Rhine, Danube).
From that starting relations the watersheds are traversed with the existing
connections of the underlying ways and nodes.
ideas for future implementations
- trace connections between ways that are not member of relations, too
- use waterway / coastline connections as starting points of watersheds
- natural=water between waterways can break the watershed
- take care of flow directions
- use a database instead of the existing simple scripts
- create the listings for the whole planet and not only on single countries
- better handling of canals that connect watersheds, such as Rhine-Main-Danube-Canal
Werner Hoch
Last modified: Sun Feb 19 18:33:44 CET 2012