Hi, Am 2014-11-23 um 23:09 schrieb François Lacombe: > As suggested on Talk page of Power transmission refinement proposal, power > lines and cable should be described with a key giving their usage in the > network. > https://wiki.openstreetmap.org/wiki/Talk:Proposed_features/Power_transmission_refinement#line.3D.2A_and_cable.3D.2A:_similarity_and_difference > > I knew usage=* and it can be the ideal key to indicate usage=transmission, > usage=distribution,... on power lines or power cables. > But it is currently and exclusively used for railway tagging. > https://wiki.openstreetmap.org/wiki/Key:usage > > Is it acceptable to extend its definition to power lines or another key > should be used? > https://wiki.openstreetmap.org/wiki/Proposed_features/Power_transmission_refinement#overhead_power.3Dline
I am one of the active railway mappers in Germany and work (togehter with other mappers) on railway tagging. The following is my personal opinion. I think that there is no problem do use a key like usage=* for two kind of objects. There are already some keys in use which spread over several object "classes", e.g. service=*, maxspeed=*, operator=* or wheelchair=*. It is used for highway=service to give information which type of service street it is. If service=* is tagged on a ways with railway=rail/light_rail/…, it describes that this track is *not* an important track. Only siding, yard and crossover tracks get service=*. Tracks of a long railway line running through a station do not get service=*, they are tagged with usage=*. service=* is also used for waterways. https://wiki.openstreetmap.org/wiki/Key:service I do not know why anyone should tag one OSM way both with power=* and railway=*. Catenary of a railway track is mapped by tagging electrified=contact_line, voltage=* and frequency=* onto the railway way. There are already some ambiguities with maxspeed=* one trams running in street. These are solved by either mapping the street as two ways (if a barrier is between) or mapping the tram tracks as two tracks or (if a circular/one-track tram line) mapping two independent OSM ways (as a precursor of a future tag set datatype). Just have a look at banks. A bank can be tagged with atm=yes and opening_hours=*. What's the solution? Just split the bank into a bank node and an independent atm node (if atm is 24/7 accessible). Because usage=* does not say what a OSM way represents, data users always have to check if it is a railway track or a power line. If a way has (by accident) only usage=* and neither power=* nor railway=*, this should be fixed by a mapper looking into OSM object history. I suggest you not to use network=*. In difference to usage=*, network=* does not have a fixed set of values. network=* is used (among other use-cases) for a human-readable name of a bus/tram/train/… network. I think that mixing free and fixed values in one key is worse than using usage=* for two categories. Maybe mappers start to map networks like "Main power network of XY power company" in future. Then mappers would best use network=* as public transport mappers do. We should not start at OSM to add a prefix (as namespace) in front of every tag. What about a mechanical edit changing wheelchair=yes to restaurant:wheelchair=yes? :-) Best regards Michael -- Per E-Mail kommuniziere ich bevorzugt GPG-verschlüsselt.
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