I don’t think it’s very important to list all possibilities, the main point is that they should not be connected to nothing at either of their ends, in almost all cases.
You’d have to dig through the source code for iD, the code for disconnected ways currently is here, but one thing I’d consider is that the tags marking the end of a power line should also include any tags we’d expect on a power line with a transformer on them, or any tags for when a power line moves from above ground to underground.
I’d have to agree, it’s not as simple as fixing an isolated highway, those are usually pretty obvious whether it’s a problem or whether you’ve actually mapped all you can and are able to ignore it.
Plus, power lines can abrubtly end but still be valid, and you’d need to rely on the right tags and likely a survey or street level imagery to confirm/validate that.
It’ll still go somewhere, but if that somewhere is underground, you’re not necessarily going to be able to see that from aerial imagery, or continue to map that without either surveys or a data source with that information.
There’s good arguments either way, it’s one I’d at least want to discuss with the community/developers about. Some people may just be adding poles as they see them but might not be able to link them all up.
What might not be a bad idea is looking at whether there’s any standalone QA tools for power infrastructure, I feel like the iD warnings should be something any mapper can resolve, whereas a more specific tool will be helpful for those who have more interest and knowledge in it.
I’ve ended up adding runs of power poles that terminate abruptly even when I know that they don’t in reality because the aerial imagery either runs out or I was relying on the shadows of the poles to spot them in the imagery and there’s a change to the vegetation or environment that makes the shadows harder to spot.
I think a warning here might just end up encouraging mappers to guess where it goes and I don’t think that is particularly helpful.
