Introduction
Welcome to The #questionable-edits OSM Iceberg!
Over the past 5 months I have been collating some of the strangest, funniest and most excruciating examples of vandalism, mistakes and creative mapping. This Iceberg takes its name from the #questionable-edits channel on the OSM World Discord where we share the weird, wild and wonderful things we’ve seen while mapping. It should be made clear, the intent of #questionable-edits (and my Iceberg) is not to mock, demean or dissuade novice mappers, but to educate about common mapping pitfalls and share some of the entertaining things that have been found. I myself am guilty of a number of things listed below! I’ve included over 80 items in my Iceberg, ranging from the well-known to the downright unhinged. This Iceberg is also available on the OSM forums.
It shouldn’t have to be said, but please do not harass or otherwise antagonise any users whose edits may be visible in these examples. The screenshots and changesets linked below are intended as illustrative examples, and aren’t intended to target individual mappers.
Happy April Fools everybody! (Yes I might be a day late, but I was last year too). Enjoy!
The Iceberg

The Explainer
What’s an Iceberg without a breakdown of all the lore?
First Level
descriptive names
Not every map element needs a name, but some mappers treat the name field as a challenge to come up with a descriptive name, for example ‘Morrisons customer car park’, ‘McDonald’s drive through’, ‘private driveway’ or ‘tarmac where a lovely lawn once stood’. Another curious example is this American football pitch with all the painted lines named.
landuse glued to roads
Mostly an older mapping style, where landuse is glued to road centrelines instead of ending at the edge of road areas. It can make it really hard to edit roads and landuse, especially in iD. Some landuse areas are even mapped as multipolygons, with roads serving as outer members.
large bboxes
One edit in Hanoi, another in Hammersmith. Large bboxes have caused a lot of frustration for users of OSMCha over the years, as they cover areas that weren’t edited. Often, this is a beginner who doesn’t realise they should upload their changes before moving on to a new area, but can also be a result of editing a large relation such as France or the United States.
tagging for the renderer
Not everything renders on Carto, which is ok. Some mappers have employed creative tagging to show off particular features, such as these sports field markings.
bad changeset comments
We’ve all seen them. ‘Edits’, ‘Update’, ‘.’, ‘asgsdfdgf’ or even a bunch of unreadable hashtags aren’t helpful for conveying a changeset’s purpose at a glance. Adding a bit of humour or personality to changeset comments is fine, but don’t take it too far.
not aligned to aerial imagery
Many ways and polygons are misaligned when compared to current aerial imagery, although this is usually down to each imagery provider having a different offset. Other times, features may be mapped inaccurately or at an angle, such as this town filled with triangular buildings.
copying from Google Maps
Despite being rule #1, ‘Don’t copy from other maps’ is occasionally broken. At least some mappers are kind enough to mark their changesets with source=Google Maps or tag ways source=Google Street View
unsquared buildings
Not all buildings have 90 degree corners, but most do. Not using ‘Q’ to square up buildings is a common beginner error, but is easily fixed. Here’s a particularly perplexing example.
Second Level
dragged nodes
Sometimes vandalism, sometimes accidental, dragged nodes can cause really funky rendering.
SEO spam
All businesses want to promote their brand, but names in all-caps, pois in incorrect locations and paragraphs of self-promotional material (in notes, tags or even diary entries) isn’t the way to do it in OSM. If you’re a SEO spammer, read this wiki page.
renaming cities rude things
A common form of vandalism, which usually gets reverted quickly. What did Los Angeles do to deserve this?
Gulf of America edit war
On the 20th of January 2025, the Gulf of Mexico node was on version 20. It’s now on version 140. All that fuss for something that doesn’t even render on Carto. Of course, there’s an accompanying 300 post long forum thread.
Pokémon Go edits
Pokémon Go uses OSM data to decide where to spawn certain types of Pokémon, but unfortunately that led to some players adding fake parks or mapping natural=beach in their garden to have easy access to water-type Pokémon. This doesn’t seem to happen much anymore.
typos in tags
Very common, even for experienced contributors. Some typos are funnier than others, for example operator:type=pubic, social_facility:for=pregrant, building=semi_permanenet_house and hundreds of roof:shape values, which gave me a good laugh. Or how about a Wikidata Qid pasted in name=.
individual trees as natural=wood
Isolated trees should be tagged as a natural=tree node, but some mappers like to trace a natural=wood way around the crown of each tree. This was also a technique used by golf mappers, as their software would render natural=wood areas but not natural=tree nodes.
broken multipolygons
Multipolygons are hard :/ . Outers crossing outers, inners outside outers, duplicate multipolygons and incomplete outer rings are just some of the ways multipolygons can be broken.
Third Level
golf mappers
There are golf simulators which can import courses from OSM, but many incorrect edits were made to golf courses as a result of incorrect tutorials and forum posts, including mapping individual trees as natural=wood areas, avoiding using multipolygons at all costs, drawing highway=service over main roads, tagging all buildings as office=yes and even tagging a natural=bay as golf=water_hazard. Thankfully, improvements to the import software means these kinds of workarounds aren’t required anymore.
Microsoft AI building slop
Particularly in the UK, buildings imported en-masse from Microsoft’s computer generated building footprint database are of poor quality, not matching reality well and clumping semi-detached and terraced buildings together. I even made a whole forum thread expressing my concerns about the huge amount of poor quality buildings being imported.
blindly fixing validator errors
While iD’s validator is very useful for finding errors in edits, some mappers feel they have to ‘resolve’ each issue before uploading, even if they haven’t checked the tag upgrade or geometry change is correct. Some examples include tagging crossing footways as bridge=yes instead of connecting them, and roads overlapping buildings with layer=-1 when the building should really be repositioned.
funny real names
Sometimes, poi or place names sound so ridiculous you think they must be vandalism, only to discover no, it really is called that. MTB trails often have crazy names such as ‘Sponge Bob’, ‘Lumpy Gravy’ or ‘Grannies’.
unnecessary multipolygons
In most areas, it’s agreed that multipolygons should only be used where absolutely necessary. However, some mappers choose to make multipolygons out of what could otherwise be closed ways, just because they share nodes with other ways. As as example, this school car park where every individual parking space was a multipolygon, or the country of Sweden.
deletion of Tel Aviv
A major wave of vandalism hit Israel in 2023, with large parts of Tel Aviv being deleted. The DWG undertook a complex revert process, and the situation ended up in the media.
overnoding
What’s the minimum distance allowed between two nodes in a way? 1 metre? 10 centimetres? 1 centimetre? Answers on a postcard please.
extremely large landuse
Sometimes a relic of old landuse imports, lots of landuse areas could really do with splitting along roads, railways or other natural features. Romania has farmland the size of cities, and Uganda has residential landuse covering 260 square kilometres.
farmland instead of meadow
Farmland is for arable crops, meadow is for grazing animals and growing hay (at least according to the wiki). However, large swathes of Ireland, the Isle of Man and the UK are tagged as farmland instead of meadow. We have a project ongoing to turn our islands green.
2.5D buildings
A classic, using buildings and other tags to cause apartment blocks to appear in 2.5D on Carto. It’s a shame it had to be deleted, because it’s a real work of art.
fake islands and cities
Perhaps someone mistook OSM for OpenGeoFiction, and mapped fake cities in South Sudan and Antarctica.
Fourth Level
not replying to changeset comments
All too common is users ignoring changeset comments asking why they’ve mapped a certain way or providing advice how to improve their mapping. Communication and discussion is an important part of OSM, so remember to always keep changeset comments polite and respectful, even if you get ignored!
naughty landuse shapes
Not all suspiciously shaped geometry is vandalism. Some islands were just made that way.
poor quality HOT edits
HOT has a bit of a mixed reputation on the OSM World Discord, sadly as a result of poor training or validation in some cases. Like, what is this? Changesets tagged with HOT projects have also been used to add a secret bunker on Little Saint James, an animal shelter for fish and Bikini Bottom.
name:ru edit war
A major wave of vandalism was visible worldwide in 2024, when a group of activists attempted to delete name:ru en-masse from the database, and proceeded to abuse users who reverted the vandalism. Roads were dragged across oceans and renamed offensive names. The forum thread is here.
razed railways
Despite OpenHistoricalMap existing, many mappers still continue to add railways that were removed decades ago and have no trace on the ground. These long-gone railways are either mapped through open fields, or tagged on existing motorways. The prefix razed: implies that no physical presence remains, but nearly 40,000 razed:railways exist in the database. There’s a 370-post forum thread dissecting the issue.
‘secret’ MTB trails
A vandalism campaign that’s been ongoing for a while now, where some mountain bikers think their ‘secret’ informal trails shouldn’t be mapped. Vandalism includes deleting trails, renaming trails, and abusing users who revert the vandalism. I call them ‘secret’ trails, because they are visible on the Strava heatmap. One user even posted a link to a photo as proof a trail was renamed, but that link was an ip logger, and another made stickers insulting an OSM editor and stuck them on signposts!
separate sidewalks without crossings
Drawing separated sidewalks along streets, but not connecting the footway at any crossing points, particularly in neighbourhoods where only unmarked crossings are present. This completely ruins foot routing.
Farming Simulator edits
Various Farming Simulator games allow importing real-world farms from OSM, but this has resulted in users adding nonexistent forests and roads or adding nonsense names to farmland, to alter the farm that ends up in their game.
Maps.me personal bookmarks
Many users who wanted to create personal bookmarks in Maps.me unknowingly uploaded their notes to OSM, resulting in hundreds of shop=books or shop=bookmaker being created across the world. Many pois named ‘My house’ or similar exist for this same reason.
Fifth Level
anonymous notes
Spam, abuse, personal notes and unclear information can all be found in OSM notes, but some users believe anonymous notes pose a major part of the problem, with no accountability for vandals or way to contact the original poster for more context. Here’s the obligatory 170-post forum thread.
DWG member slander
The DWG do a lot of hard work cleaning up the map, resolving disputes and banning vandals, but some people respond with personal attacks, be that in notes, diary entries or edits with sockpuppet accounts. I’m not going to republish any, but I’ve seen plenty.
deleting sensitive sites in South Korea
Last year, a wave of vandals attempted to delete sensitive facilities from OSM in South Korea, namely military bases, power plants and intelligence sites. Part of the vandalism could have originated from media reports that OSM was publishing locations of military bases, which are not visible on domestic South Korean maps.
theme park mapping
Theme parks have a lot of decorative features which mimic real world features, making tagging challenging. Often there’s a lot of tagging for the renderer, such as natural=cave_entrance being tagged on rollercoasters as they enter buildings, tagging decorative flames as leisure=firepit or splitting pedestrian areas based on the colour of paving stones.
disconnected paths/roads
The ends of routable ways being extremely close to the nodes they should be connected to, breaking routing but appearing connected on Carto. The result of ignoring validator warnings.
vibecoded editors breaking the map
A relatively new phenomenon, users creating their own editors with AI, then proceeding to break the map. One case involved a vibecoded editor adding tags with no values, and confusing the ids of nodes and ways, dragging a way across the ocean. Disclaimer: There’s way to tell if an editor is vibecoded, but we suspect some of them must be.
undiscussed mass edits
The Import Guidelines are strictly enforced; I’ve lost count of the amount of reverted imports I’ve seen now. This also extends to mass tagging changes which while well-meaning, still need to be discussed somewhere first.
stale data
Occasionally, someone posts some mapping that is totally wrong, only to realise it matches historic imagery perfectly. Keeping OSM up-to-date with real-world changes is a big job; many places have shops mapped that have been closed for 10 years or more.
tagging for the (3D) renderer
3D building parts can be used to create some impressive rendering of landmarks, but some users stretch the definition of what can be called a building, to be able to use building parts to map them. This might include a roundabout median, aircraft on display, compost bin (view on F4map) or advertising signs and walls.
Sixth Level
warnings in name=
We don’t map subjective opinions, but some mappers feel they need to warn map users of certain hazards, for example dangerous cliffs, bad smells, insects, scammers or litter.
TIGER cringe
TIGER data, imported in 2007, provided the backbone for all mapping in the USA. However, it’s out of date and imprecise by modern standards, and despite a large effort to clean it up, lots of original data still remains.
impossible tag combos
Tags that don’t belong on the same object, like natural=water and shop=, or building=residential and highway=path, or shop=hairdresser and maxspeed=20 mph. Or alternatively, invalid semicolon separated values, like building:levels=2;1.
physical separation
Road lanes should only be drawn separately when separated by a physical barrier, but complex junctions or places where lanes are divided by painted medians can cause disagreements over the best way to map roads. This thread has some cursed examples.
deleting things I don’t understand
With the great depth of tagging, there’s always going to be tags that are confusing, especially to new users. But not understanding what addr:interpolation ways are doesn’t justify deleting them.
name= instead of addr:housename=
More of a personal gripe is houses and apartments in the UK which are tagged with name= instead of addr:housename= . Or equally annoying, houses tagged with both a name= and addr:housename=.
ending landuse at task boundaries
If you’ve ever participated in a project that uses a tasking manager, you’re sure to have seen the message ‘Do not map outside of task boundary’. Unfortunately, that advice produces some pretty poor results when applied to landuse, resulting in the map looking more like a patchwork quilt than a cohesive landscape.
don’t map my private property
We map private driveways, trails, paths and other features that are visible from aerial imagery or street level (with appropriate access tags). Many landowners have objected to this over the years, deleting trails on their property or adding name=Private (No Entry). See ‘Why can’t I delete this trail’.
Seventh Level
name=My House
Whether by accident or ignorance, numerous users have named their own house on OSM, or the house of a friend or relative. Obviously, we don’t map private information in OSM, so report any you find to the DWG for redaction!
watsan:toilet_status=
My personal least favourite OSM tag, this tag is used to record the cleanliness of toilets.
insulting my enemy
Having a disagreement with your neighbour? Why not rename their house something insulting? Surprisingly, this vandalism wasn’t noticed for three-and-a-half years, at least until the original user made a Reddit post (archived version) bragging about it. Or alternatively, tell the world what you think about your teacher.
vandalism unnoticed for years
Similar to Wikipedia, vandalism on OSM can go undetected for years unless someone specifically looks for a tag. I’d be curious to know what the oldest vandalism people have found was.
source=AI generated image
Related to the ‘secret’ MTB trails, when vandals were told to provide proof for trails being renamed they responded with AI generated photos of trail signage. (And then they vandalised the sign).
not a heath
natural=heath is intended for a very specific dwarf-shrub habitat, mainly covered by heather. However, Wales is covered with huge areas tagged natural=heath, used to represent named upland areas or nature reserves, despite the fact they’re mainly grassland. Grassland is not a heath!
private info pasted in tags
Mapping while at work is a widespread practice, or so I’ve heard. Just be careful not to paste confidential information from work documents into OSM tags…
email=female
It’s apparently a language barrier thing, but French mappers like mixing up email= and female=
not using lifecycle prefixes
When mapping the construction of a new project, it’s common to use proposed: and construction: prefixes to indicate that the physical feature isn’t finished yet. I found a proposed airport mapped as if it were completed.
Eighth Level
every key has 1000s of nonsense values
If you go to the final page of any key on taginfo, you’re bound to find dozens of nonsense tags, for example cuisine=Rolex, or this ‘bar’. There’s too many to list, so see what you can find.
mapping clouds
Clouds turn up on aerial imagery from time-to-time, but tracing the shape and tagging them as natural=bare_rock, natural=glacier or even natural=water is clearly wrong.
abbreviated road names
Names in OSM should be recorded unabbreviated, so don’t type Road as Rd, Drive as Dr, or Street as St. Abbreviation can be performed by data consumers, if they wish.
water=ocean
Technically, oceans are the only thing not mapped in OSM. Or they would be, if not for a handful of natural=water + water=ocean.
source=ChatGPT
Yes, people do really rely on the output of AI chatbots to inform their mapping. Who knows what kind of hallucinated information might end up in OSM tags.
pedestrian area misuse
It is generally agreed that highway=footway + area=yes should be used for pedestrian plazas, and area:highway=footway for linear, routable streets and paths. That doesn’t stop many linear areas being mapped with area=yes, presumably because it renders on carto.
skibidi Ohio rizz sigma amogus
Every new fad, phrase and meme causes a bit of vandalism from (presumably) children. Thankfully, it’s quite easy to query for name=amogus. I wonder if there’s a 67 Church somewhere.
flooding of Great Britain
A vandal added natural=water to the Great Britain relation, resulting on tiles in England, Wales and Scotland rendering with a blue background for a few days.
Ninth Level
maxspeed:beast
Clearly signed, this bridge has both a maximum speed and capacity which applies to any beasts you may be leading.
McDonald’s with 56 names
It’s a McDonald’s with its name tagged in 56 different languages.
Kim Jong Un’s secret base
Who knew, Kim Jong Un has a secret base on the Canada-US border. (Is it secret if it’s on OSM?) It’s rumoured that he also had a secret base mapped in Greenland, but I can’t find any evidence for this.
source=brain
Used when fixing an error so blatant no survey or aerial imagery is required, for example building:levels=2000.
Republic of Pandora
Vandalism creating a new country just before an Organic Maps data snapshot was taken made it appear the Republic of Pandora had seceded from the United Kingdom for about two months.
Church of (your name here)
Many fake churches with novel new religions have been created, but Mattism might be my favourite.
Federated States of Barbie and Oppenheimer
Barbenheimer in OSM, who would have thought it.
Who did this? Me?!
If it hasn’t happened to you yet, it will. You stumble across something ridiculous, incorrect or confusing and think, “What idiot did this?” Then, you check the history and realise, it was in fact, you. 🤭
Tenth Level
Chinese oil refinery
This entry is the original questionable edit that inspired the Iceberg. An oil refinery, mapped in such an incorrect way, it was impossible to view the area in iD. Mapping so perplexing, it had to be shared with the world. Well, not that it exists anymore (#RIPChineseOilRefinery). The imagery quoted as a source in many of the changesets was extremely high resolution drone imagery, and clearly was some kind of commercial project to map the refinery for internal purposes. However, drawing dense grids of footways (over 20,000 highway=footway in one refinery) to represent pedestrian areas was a choice, and the user’s diary entry didn’t provide much explanation either, declaring “Refine the Fire Pit” almost 200 times. It even featured a building that looked shellshocked by the mapping going on around it, so we made it our unofficial mascot. I even 3D mapped it.
Cat Ba bridge
One of the more determined fantasy mappers, who unsuccessfully tried to prove a bridge that doesn’t exist, does. A video of the bridge mapped in iD is in fact not proof that it exists.
dogging=likely
This tag was added to a car park by an OSM administrator, so it must be reliable. There wasn’t any source given.
#Living_credits
This entry has no explanation. Do not read the lore unless you want to go down a very, very deep rabbithole.
OSM Rule 34
This entry is a JOKE, and is a saying I came up with: “OSM Rule 34: If you can think of a new tag, it already exists”
Free Centrist State of Derryounce
What’s the number one priority for a group of friends trying to establish a micronation in an Irish peat bog? Map it on OSM of course, to advertise your fledgling new nation to the world.
Adolf Hitler Mapping
Adolf Hitler did make it to Moscow, albeit only in OSM.
JeffreyEpstein blocked by DWG
Not much I can say really. He was blocked after one edit for vandalising MTB trails. Probably for the best.
Acknowledgements
My Iceberg was inspired by Xvtn’s OSM Iceberg, created in 2024. I’d like to thank everyone who’s posted their finds in #questionable-edits over the last few years, for providing so much joy (and pain). Thanks also go to everyone who’s spent time cleaning up the map, particularly the DWG who feature in about half of these situations.
And if you’ve made it to the end, thank you for reading. I hope you enjoyed :)
LordGarySugar