How is this power line attached: Multiple attachments

[micah]

General

Affected tag(s) to be modified: Key:line_attachment
Question asked: How is this power line attached?

The question asking "How is this power line attached" has three options:

1. Supported from above
2. Fixed horizontally
3. Supported from below

and then there is the 'Uh...' option which just has "Can't say..."

It turns out pretty much every power line in this state has more than one of those answers. Often poles are supported from below and fixed horizontally. I don't have a way to answer that.

Today, I noticed the below pole, which appears to be supporting from below, attached horizontally, and even attached vertically (on the top)!

Probably there should be an option for multiple?

[mnalis]

TL;DR: while OSM supports such complex configurations, supporting it is very likely not well suited for StreetComplete. Leaving a note with picture (or disabling the quest) might be only workable solutions.

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Today, I noticed the below pole, which appears to be supporting from below, attached horizontally, and even attached vertically (on the top)!

According to the wiki, that picture should be properly tagged (unless I miscalculated) as line_attachment=(anchor|pin|anchor)|(pin|pin|pin)|(anchor)|(anchor)|(anchor).

Probably there should be an option for multiple?

Maybe, but what would should StreetComplete tag to satisfy quest guidelines when such "multiple" answer is chosen? Especially:

🤔 No unanswerable quests: All generated quests need to be actually answerable (no false-positives). This means that any answer given by the user must result in something being tagged

While OSM has suggested tagging for tagging such complex configurations (see https://wiki.openstreetmap.org/wiki/Key:line_attachment#Complex_configurations), we should note that:

• vast majority (~98%) are one of the 3 simple values; more complex configuration are used on less than 1% of line_attachment=* values (affects "🚧 Established tags only" and "🕓 Effort vs impact")
• it would require much more complex UI to specify what type(s) are used at which "levels" (especially affects "🐿️ Easy answer"), which is not well suited for StreetComplete.

As for how to handle that, I don't think there is a good and easy solution. We may do one or more of the following:

• disable the quest by default (especially if such complex configurations are common elsewhere too) so only people who care enough about that data (and have educated themselves on mapping its intricacies) would enable it
• include (i)info box explaining to the user that if there is more then one simple configuration, they should do one of the following:
  • disable the quest in settings if such situations happen too often so have become bothersome, or
  • long press to edit the location in another more full-featured editor (like Vespucci or SCEE's raw tag editor)
  • leave a note with picture -- if they care a lot about that information, and it is rare enough (and especially if they intend solve the note themselves later)

[peternewman]

FWIW I've also seen quite a few, especially where the network splits off, where say the main line is above/below and the split is fixed horizontally (as it's the start of a new route).

[mnalis]

FWIW I've also seen quite a few, especially where the network splits off

You mean things like line_managment=split/transition and the like?

Yeah, those also add to the complexity... And then there are line_arrangement=*, power=terminal, line_management=*, utility=*, location:transition=* and other keys...

Power infrastructure mapping is anything but easy 🤷 and probably only the most simple cases are suitable for StreetComplete at all (esp. given "👨‍💻 Users are no experts" and "🐿️ Easy answer")

[peternewman]

You mean things like line_managment=split/transition and the like?

Power infrastructure mapping is anything but easy 🤷 and probably only the most simple cases are suitable for StreetComplete at all (esp. given "👨‍💻 Users are no experts" and "🐿️ Easy answer")

Yeah what I saw was probably line_management=branch.

Should we adapt the SC filter to remove line_management=branch/split and maybe transpose and cross as ones that are likely to have more complex attachments to avoid having to annotate these manually with notes? It seems from taginfo there are some with line_management tagged but not attachment type I think?

[matkoniecz]

pinging as an expert @Jean-BaptisteC who made #5382

[micah]

Thanks for the answers. I have disabled the quest because every single power pole in this entire region is configured with both horizontal and vertical attachments, and leaving a note with a picture for every one is too much.

I understand that there are a number of complex configurations out there, but maybe instead of getting into complex configurations, a more simple set of options could be presented:

1. Supported from above
2. Fixed horizontally
3. Supported from below
4. Supported from below and fixed horizontal
5. Supported from above and fixed horizontal

Certainly for this area, which is about 180k sq. km, and filled with power poles of option 4. Certainly, there are occasional complex configuration poles (like the one I posted in the initial issue image), but these are not common, here option 4 is everywhere.

I fully understand the complex, multi-level configurations are way too difficult to represent in the UI, however I realize that my initial issue was opening up the problem much wider than what I really was interested in, which was supporting the pole configuration where there is both supported from below and horizontal on every pole here.

[mnalis]

4. Supported from below and fixed horizontal
5. Supported from above and fixed horizontal

Agreed, but what do you @micah propose that StreetComplete should actually tag (i.e. what key=value) for those choices?

It seems to me that OSM community has only solutions for:

• very simple configurations (options 1-3, currently supported in StreetComplete), or for
• very complex configurations (mentioned above, and too complex for StreetComplete);
• but it seems to lack established simpler tagging for such semi-complex configurations like 4 & 5 that you suggest...

The main issue is that StreetComplete has a policy that it shall not "invent" tags -- it should only support tags that are already "established" (i.e. documented and in widespread use by wider OSM community).

And unless I missed something, neither the documentation for the line_attachment=* wiki nor the established usage for that tag¹ seem to support such medium-complexity tagging like 4. and 5., so it is unknown what StreetComplete should tag for those. ².

Footnotes

1. there are few dozen (about 0.01%) usages worldwide of line_attachment=suspension;anchor which seems to do what you want, but that is IMHO both undocumented and much too rare to be offered by StreetComplete (at least without further wider OSM community acceptance). ↩

2. And if such wider OSM community agreement on what to tag is missing (as it seems to me), one should first seek acceptance on OSM community forum or even going with full OSM proposal process before updating the wiki and coming back to this StreetComplete proposal when it is clear what key=value should be tagged for such cases. ↩

[Jean-BaptisteC]

For these cases, there are no any easy solutions to be able to exclude or support complex cases.
From my own experience, complex cases are present in the most of case on minor lines (lines under 1000 V or lines under 50 000 V)

• For lines under 1000 V with one conductor or three conductors twisted, the wiki recommend to use power=cable -> this case is not concerned because power=cable was ignored by StreetComplete but a lot of minor lines are uncorrectly tagged in osm with power=minor_line instead power=cable
• For lines 1000 V with three conductors tagged with power=minor_line we can exclude by filter with > 1000V but a lot of minor line doesn't have voltage tag, you can check usage of voltage tag on different line with openinframap

[mnalis]

For these cases, there are no any easy solutions to be able to exclude or support complex cases.

We might probably drop power=pole|tower nodes which are part of more then one way (I don't know how easy/expensive that check would be) to reduce chances of quest being asked on complex configurations, thus reducing the "complex quest spam".

But it would only help if the electrical infra (i.e. all the power=line|minor_line|cable ways) was well-mapped (and if it was, it might indicate power infra OSM mappers are active there; so is also somewhat likely that line_attachment=* would also be properly mapped, so quest wouldn't be asked anyway).

[westnordost]

(removing "enchancement" because it is unclear how to solve this, i.e. it is not actionable yet)

I understand from the two last comments, that this issue cannot really be resolved by more strict filtering?

[peternewman]

(removing "enchancement" because it is unclear how to solve this, i.e. it is not actionable yet)

I understand from the two last comments, that this issue cannot really be resolved by more strict filtering?

I'd like to somewhat dispute that please if I may?

Should we adapt the SC filter to remove line_management=branch/split and maybe transpose and cross as ones that are likely to have more complex attachments to avoid having to annotate these manually with notes? It seems from taginfo there are some with line_management tagged but not attachment type I think?

I can find a good non-zero number of nodes with some of the forms of line_management mapped but not line_attachment mapped e.g. https://overpass-turbo.eu/s/2eHs so changing the filter to exclude these would exclude some potentially problematic poles from being asked for what I think is minimal computing cost and complexity.

We might probably drop power=pole|tower nodes which are part of more then one way (I don't know how easy/expensive that check would be) to reduce changes of quest being asked on complex configurations, thus reducing the "complex quest spam".

Like @mnalis I don't know how expensive that query would be, but isn't something similar already being done for some of the crossing/kerb quests?

But it would only help if the electrical infra (i.e. all the power=line|minor_line|cable ways) was well-mapped (and if it was, it might indicate power infra OSM mappers are active there; so is also somewhat likely that line_attachment=* would also be properly mapped, so quest wouldn't be asked anyway).

I can find plenty near me that aren't mapped in as much detail as possible, assuming some have the lines themselves mapped. My theory would be you could potentially amchair map the poles, and maybe even the wires if they show on aerial imagery, or certainly at a far greater distance surveying than being able to see the specific attachment methods.

[westnordost]

@flacombe, the author of the power line attachment quest hasn't been mentioned yet, so I'll ping him here in case he has an idea what could be done.