A list of possibly deprecated, but rendered tags:

[tyrasd]

After reading the guidelines I've hacked together a script that searches for typos and deprecated tags in the openstreetmap-carto stylesheet. It does this by searching for key-value tag selectors in the cartocss stylesheets and cross-checking those with the taginfo databases. Tags that can't be found on neither the tables for popular tags nor the table for wiki-documented tags are filtered out.

In the end I've come up with the following list of tags that are rendered in openstreetmap-carto, but are undocumented and not used widely:

aerialways.mss

• aerialway=j-bar
• aerialway=rope_tow

amenity-points.mss

• amenity=bus_stop stop rendering amenity=bus_stop #667
• amenity=chalet Remove style for amenity=chalet #226 Change amenity to tourism for chalet #238
• waterway=lock
• amenity=picnic_site fix this bug https://trac.openstreetmap.org/ticket/2832 #208
• tourism=bed_and_breakfast stop rendering [tourism = bed_and_breakfast] #695, refactoring amenity-points #1059
• landuse=grave_yard Drop landuse=grave_yard #793

buildings.mss

• building=station

landcover.mss

• natural=field Remove natural=field rendering #617
• landuse=grave_yard Drop landuse=grave_yard #793

placenames.mss

• place=metropolis Remove place=metropolis #224
• place=large_town Remove large_town, small_town #225
• place=small_town Remove large_town, small_town #225
• place=large_village Remove large_village #223

roads.mss

• highway=runway Remove highway=runway and highway=taxiway rendering #206
• highway=taxiway Remove highway=runway and highway=taxiway rendering #206

water.mss

• waterway=mill_pond
• landuse=water

[gravitystorm]

Awesome work

[dieterdreist]

2013/9/30 Martin Raifer [email protected]

In the end I've come up with the following list of tags that are rendered
in openstreetmap-carto, but are undocumented and not used
widely:aerialways.mss

+0.97
the only 2 that might merit reconsideration are

building=station (is this the same as building=train_station?)
waterway=lock (is this the same as waterway=lock_gate?)

both used more than 1000 times (but admittedly they seem undocumented what
makes it hard to say what they are used for, e.g. there are also
power_stations etc. and it seems better to advocate expressive tagging with
the main style).

[matthijsmelissen]

highway=runway
highway=taxiway

Those should be aeroway.

[pnorman]

point=yes is not a tag in the stylesheet but is from a column coming from the SQL.

The MSS comes up within the selector .text where the SQL #text and #text-poly both have the class but they generate the column 'yes'::text as point and 'no'::text as point respectively. It is, as is probably obvious, a confusing way to do this.

[matkoniecz]

natural=field rendering was removed in #617

[Zverik]

Please do not deprecate tags that are widely used, just because someone on wiki decided on a better alternative. E.g. amenity=emergency_phone is used 7k times, emergency=phone — 27k.

[matkoniecz]

water.mss

Two are unused and undocumented: waterway=mill_pond (used 3 times) and landuse=water (246 times + clearly replaced by natural=water). I plan on making pull request that will remove rendering for these tags.

natural=marsh is used 11 836 times, JOSM validator detects it and suggests change. Usage is to high to stop rendering it now, waiting a year or two is probably preferable.

[matthijsmelissen]

What is the evidence that barrier=embankment and landuse=conservation are deprecated? Both are used 1000s of times.

[matkoniecz]

"possibly deprecated" (AKA no page on the wiki)

[matthijsmelissen]

Ok, I removed these two from the list.

[matthijsmelissen]

Removed natural=marsh, does not seem to be deprecated.

[pnorman]

waterway=mill_pond has two uses on ways.

[matthijsmelissen]

landuse=graveyard has been dropped by #793.

[matthijsmelissen]

landuse=conservation is still in widespread use so I will remove it.

[matkoniecz]

building=station

Wiki recommends building=train_station ( http://wiki.openstreetmap.org/wiki/Tag:building%3Dtrain_station ). What would be better - rendering both or only building=train_station?

[matkoniecz]

amenity=emergency_phone

It is covered by #318 and requires database upgrade (I edited OP and removed it from this list)

[matkoniecz]

waterway=lock

Undocumented, in rendering assumed to be a node (it shows lock_gate.png symbol), only 298 instances of nodes, entire usage found by Overpass that I checked is duplicated by documented tags. It also seems to be removed in #991 PR.

[matkoniecz]

building=station is no longer considered special.

[pnorman]

all resolved.