User:Mateusz Konieczny/ruined building

How many buildings are on this picture? How they would be tagged?

This is only about tag for structure itself - tourism=attraction, name=* etc apply as usual.

(note that it is an incomplete draft not consulted with wider community so if someone has feedback it is welcome)

Some problems:

• there are cases where already mapped building was demolished and gone with no trace remaining but is still visible on aerial imagery
  • in such case it is useful to mark what is going on and temporarily preserve its geometry
  • note that it does not mean that intentionally mapping no longer existing buildings is helpful, use OpenHistoricalMap for that
• there are also cases of ruins remaining
  • note that this often overlaps "there was building here but is not anymore" but it is not the same

You can have cases where

• building used to exist and is gone without any trace
  • can be temporarily preserved to avoid people remapping it - but only temporarily, use OpenHistoricalMap for mapping such features
  • you can have cases where you have memorial plaque or other trace like this
• building used to exist and its ruins are still existing
  • ruins may be substantial or barely visible
• pile of rubble is in place, building never existed here
  • pile of rubble was moved
  • building was never constructed or construction was abandoned
• building is damaged but not ruined
• building is lightly damaged or not damaged but defunct anyway (for example abandoned)
• building is not damaged (normal situation, does not require special handling)

Building

See building=* and building:use=*

Abandoned building

Abandoned building (was abandoned during construction and unfinished)

Still building, so building=* + abandoned=yes

abandoned:building=* is in some use but not recommended as it makes OSM data more complicated to use, without a good reason

Note that building may be abandoned and not damaged (TODO: find an example), it also can be not abandoned and damaged. People sometimes live in heavily damaged buildings.

TODO: what to do with buildings which are historic sites? Forum Romanum is not abandoned at all. But original use of these buildings is abandoned.

TODO: what is the difference between building=* + abandoned=yes and building=* + disused=yes

disused:building=* definitely has the same problem as abandoned:building=* and should not be used

Damaged building, not ruined

Damaged, not ruined and not abandoned building.

Still building, so building=* + potentially tags to express its damage (not covered here)

Heavily damaged building

heavily damaged, still a building

Building is ruined but is still a building - has roof and walls. building=* ruins=yes

Walls and skeleton of roof remains

Is it still building?

building=* ruins=yes Still considered as a building, though I can easily imagine people judging it differently.

Roof is gone

Is it still a building?

Is it still a building?

Building or not?

building=* ruins=yes

Or is it not a building anymore?

Remaining standing wall/walls can be mapped with barrier=wall

Only parts of wall are standing

Temple of Saturn - only few columns and structure above them remains

Likely should not be marked as building?

And these remains are not building either? And mapping them as building is likely mistagging for the renderer

Historic sites

Temple of Saturn is not a building anymore, mappable as an archeological site and tourism attraction

So historic=archaeological_site or historic=ruins may apply.

tourism=attraction or tourism=museum may apply

Roof and walls are gone

Mappable remains of a building, but not a building=* anymore

Ruined remnants of a building.

so damaged that it is not a building anymore, pile of rubble, stumps of walls etc. are remaining - ruins:building=yes

Roof and walls are gone but cellars are remaining

?????????

Nothing left, still used as a name

Use place=* + name=*

For example place=locality + name=*

Nothing left, still a tourism attraction

Add tourism=attraction as an extra tag.

Likely also has name=*

Nothing left, still visible on high-quality aerial imagery

gone:building=* - is it making clear that no remains are present?

Only recently demolished buildings still visible on high-quality aerial imagery or otherwise highly likely to be accidentally mapped may be mapped this way. This is a special exception to not mapping nonexisting features and applies only in case where building is visible on standard aerials etc.

"official database has building here" is not a valid reason to add geometries to OSM

• demolished:building=*/destroyed:building=*/razed:building=* - is unclear whether any remains or ruins are present - not recommended, but in wide use
• what about was:building=*?

Nothing left, no longer visible on high-quality aerial imagery

If it is no longer visible on aerial imagery expected to be used by mappers in a given area it can and should be deleted (if you want to map such buildings then OHM is a good place for that)

Intentionally build as ruins

Also known as sham ruins

building=sham_ruins

Just a single wall

barrier=wall + ???????????

Only foundation plate

Happens with abandoned or stopped construction.

man_made=foundation

May also happen with partially destroyed building.

Known underground remains, nothing whatsoever remains on surface

????????

Nothing left, memorial or other objects are present

This memorial reminding about destroyed village (people living there were deported) is entirely mappable. Buildings gone decades ago without trace are not

Map existing objects: memorials, monuments, information boards, cemeteries etc. Do not map buildings gone without trace.

Map historic=memorial (or tag historic=monument or tourism=information or whatever else is currently present)

Note that this is not making former building mappable if it is gone.

Only memorial remains, memorial marks extend of a building

Wall in background marks extend of tower - it is not any form of remains

Still not a building but such wall can be mapped in addition to mapping memorial or be considered as a part of memorial.

Complex cases

In some cases part of former building may be a building=* part a ruins:building=* and part gone fully and not mappable at all.

List of tags which ideally would not be used

• building=collapsed - either it is not a building anymore because it collapsed (so building=* is wrong) or it has not collapsed so value is wrong
  • In every single case it should be retagged, to one of cases mentioned above
• building=ruins building=ruin building=demolished building=destroyed building=razed building=dismantled - the same
  • In every single case it should be retagged, to one of cases mentioned above
• building=damaged - use regular proper building tag. Damaged standing building constructed as temple is still building=temple - exact handling depends on stage of damage
  • how to tag that building is damaged? That is a good question, and may be worth documenting (may require inventing a new tagging)
• demolished:building=*/destroyed:building=*/razed:building=* - is unclear whether any remains or ruins are present
  • Ideally these would be also not used anymore and retagged to more specific ones, but it is not a high priority

Replacements

In each case one of following would be used:

• deleted - if remains of any kind are not present and danger of accidental remapping is low
• gone:building=* - if remains of any kind are not present and accidental remapping is likely
• ruins:building=yes - if ruined remnants are present
• building=* ruins=yes - if ruined building is there
• building=* - if building is there

Next steps with this page

• Share with OSM community, get feedback (forum, US Slack, Discord global, Discord PL)
• https://community.openstreetmap.org/t/marking-that-building-is-gone-but-visible-on-aerials-how-to-distinguish-fully-gone-ones-and-cases-where-ruins-remain/130420
• create thread asking about SC quest viability, see below "How building=collapsed should be retagged? I think it is established that building=collapsed is a poor idea. How exciting ones should be handled? Is proposed flow listed here making sense?"
• Go through RFC for proposal process

In both cases goal is to clarify which parts are just consensus and which parts are new ideas liked by community (maybe extract some proposal from this and go through a proposal process), maybe remove some parts

Maybe implement SC quest for building=collapsed and similar, attempting to get rid of such tagging?

• Is there building here?
  • Yes, there is a building here (may be damaged, but still a building) - retag to building=yes
  • Yes, there is a ruined building here - retag to building=yes + ruins=yes
  • There are ruined remnants here - retag to ruins:building=yes
  • No traces of a building - retag to gone:building=yes (or destroyed:building=yes ?)

External links

• https://community.openstreetmap.org/t/do-we-have-building-for-existing-ruins-of-a-building/97276