osm-fr / osmose-backend

Part of osmose that runs the analysis, and send the results to the frontend.
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False positive lamp post with waste bin #2243

Closed Venefilyn closed 2 months ago

Venefilyn commented 3 months ago

osmose needs to be more refined when a node has amenity=waste_basket and highway=street_lamp

It's fairly used all around and you see waste baskets attach to street lamps all over the place

The error Osmose reports is that it's unsual to use amenity= and highway= together

Famlam commented 3 months ago

Shouldn't this be bin=yes, if you're not mapping them separately? Otherwise you're not mapping according to one feature, one element.

For instance, add colour=yellow, and tell me if this is the color of the bin or the lamp post. On the other hand, bin=yes only says there's a bin around, not that the lamp post "is" also the bin.

Venefilyn commented 3 months ago

To me it doesn't make sense that we have two different systems like this. Given that bin=yes can be on it's own as well without anything else it doesn't help things.

From what I gathered, for 99% of all items they will be tagged as bin=yes if it's on a transit platform as most apps suggest that. But I haven't seen many that are attached to things https://taginfo.openstreetmap.org/compare/bin=yes/amenity=waste_basket

Even if you were to add colour=yellow when an item has a bin=yes you wouldn't be able to accurately figure out what is being coloured

Wonder if this is just a case for a proposal, the whole situation irks me :thinking:

501Ghost commented 3 months ago

I recommend mapping the street lamps and waste bins as separate nodes. You can give the waste bins a support=* tag to indicate that they're attached to a lamp post.

jajajaneeneenee commented 3 months ago

I would also tag it as 2 separate nodes (amenity=waste_basket with support=street_lamp).

On a street lamp, also other things can be attached, for example guideposts (tourism=information, information=guidepost), emergency access points (highway=emergency_access_point or emergency=access_point), excrement_bags (vending=excrement_bags), .... And I already saw 3 or 4 different things attached to a street lamp ...

Therefore, mapping as separate nodes is probably the only sensible option, even if this results in confusing "node stacks".

Unfortunately, OpenStreetMap lacks a really good tagging concept for such "multiple features" in one place.

Famlam commented 3 months ago

As fixing the "multiple features" issue of OSM is a bit out of the scope of Osmose I suspect this issue can be closed until OSM itself has found a solution?

jajajaneeneenee commented 3 months ago

I also think this could be closed ...

Only one thought: I don't know the exact text of the warning, sometimes the wording makes a difference (and a nicely worded advice that it is usually better to tag different features separately might be helpful).

Famlam commented 2 months ago

Only one thought: I don't know the exact text of the warning, sometimes the wording makes a difference (and a nicely worded advice that it is usually better to tag different features separately might be helpful).

At this moment, the warning message is:

Tag conflict Conflict between tags: amenity, highway

with the description in the side column:

The object contains two incompatible tags.

We could maybe rephrase the latter to:

This object has two tags that represent multiple features. According to the principle of one feature, one OSM element, these should be mapped as separate objects.

(Suggestions welcome. Note that the same analyser also warns for things you really won't find together, like a waterway and an aeroway)

Venefilyn commented 2 months ago

I think that would work, if it's unintended you would still be able to look at it and see what's wrong. 100% for rephrasing the message

jajajaneeneenee commented 2 months ago

Also 100% for rephrasing. Better wording can make a difference.

The text is fine I think and a good improvement. Another variant could be (but I am not a native English speaker)

This object has two tags that represent different features. According to the principle of “one feature, one OSM element”, these should better be mapped as two separate objects.

And not sure if something like this should be added:

(Even if it is exactly the same position and seems to be clear which tags belong to which feature.)

Because that is probably the decision problem that has led many mappers (including me) to double tagging.

In addition, the principle “One feature, one OSM element” is not a really easy principle (only see the looooong text of the Wiki page).

Some other thoughts, maybe a little off-topic (but connected):

For me still a little confusing (after many years of mapping):

I just want to point out that conflicting Osmosis warnings can occur, which is frustrating (and confusing) and no clear solution is provided. But again, it can be a reason for double tagging, because from a human perspective it is very often clear which tags belong to which feature (not always, of course), and double tagging seems to be the easiest way to go.

But a first step could be a rephrasing here ...

Famlam commented 2 months ago

I agree it's a pretty complicated topic with many difficult/debatable cases. I've made a PR to update the text.

Famlam commented 2 months ago

The updated text is live. (Translations will follow later, that's a manual synchronization)