A lot of times, jersey barriers on highways are simply a long chain placed end-to-end. It’s quickest to simply map the chain of jersey barriers as one long way, but one could conceivably also map each individual segment of jersey barrier. This could be done rather simply in JOSM: first map the long way, then select all nodes, then separate the way at each node.
I’m just curious what counter arguments exist against this.
I’d say mapping the single elements of a jersey barriers just for sake of micro mapping would not add any value to the data so I would refrain from it. On the other hand I believe there is no rule saying you are not allowed to do that.
Btw: would you mind to cut the headline down to something like “Mapping of jersey barriers” so that it would allow a smoother reading in the topic list ?
Of course. I’m just curious what the thoughts of others are on the topic.
Will do.
If they are all identical, it might be easier for maintainance to just add the length of each barrier or how many there are. E.g. jersey_barrier:length=2 or count=10
This is much more precise anyway than splitting the way every 2 meters and still allows rendering of each individual barrier.
A Jersey barrier is a substantial crash barrier made of concrete (or sometimes out of plastic filled with something heavy in a similar K-rail shape). A high-tension cable barrier should be tagged barrier=cable_barrier. A looser chain would be barrier=chain.
You absolutely can map a longitudinal barrier as a way along the median or along the edges of the roadway, and this is already common in some localities. As with a lot of micromapping, this is going to be more useful for detailed rendering (especially in 3D) than for navigation, but by itself that shouldn’t be a reason to refrain from mapping something you want to map.
If you really want to indicate where the posts are, I don’t think splitting the way will indicate that very clearly. Tagging the way with the number of posts could be fragile, too, if the way ever gets split for some reason. You could tag each post’s node with man_made=post, or tag the way with something like support=post support:interval=2 m.
if I were mapping barriers like these, I’d probably just mark out the whole line as one way
that said, if you do want to map these, I’d probably use a similar scheme to power line tagging, with a way along the whole line (with tags describing the barriers themselves) and nodes at each post (for cable_barrier and chain) or joint (for jersey_barrier)
makes map maintenance harder without any real benefit
Yes, that is indeed the general sentiment against this kind of micromapping, but I don’t really agree with it. Some of what we map can have benefits besides any day-to-day usage in standard data consumers. For example, much of the detail being added for wheelchair accessibility is meant to facilitate not only wheelchair routers but also analyses that can influence local decisionmakers. In the same way, mapping a chain barrier along an expressway could help someone call attention to a safety issue, a need to consider a more substantial barrier to mitigate crossover impacts. This prospective mapping won’t be useful until someone cares enough to make something out of it – possibly a chicken-and-egg scenario.
Agreed.
Data is valuable, and you don’t know what people will or will not use out of OSM data.
I believe the question does not refer to a barrier made up of a long chain fixed to a row of posts but to a linear barrier made up of row of jersey barriers put together end by end to form a wall in between two carriageways. So it is kind of a long chain made up of the single jersey barrier elements and the question is if it makes sense to map these elements one by one instead of mapping them as a linear object over the whole length.
Maybe I’m wrong but that is how I understood it.
I believe mapping the single jersey barrier elements one by one does not add any value, whereas in case of a long row of bollards for instance it could be helpful to know where the single bollards are placed and mapping them separately therefor could make sense.
The latter is exactly what I meant! Thank you for clarifying it better than I could 
I couldn’t come up with a better way to word the title at the time.