Deprecate man_made=windmill


I would like to probe the community about deprecating man_made=windmill and give preference to building=windmill.
As it is now, we have to add building=yes (or building=windmill) so that the wind mill is correctly rendered in the map.
Thus, it doesn’t make sense to have two tags when you can have only one, which fits perfectly into the building=* scheme.
The wiki page for building=windmill already exists:

The same could be said about building=watermill.

What do you say?

What about windmills and watermills that aren’t buildings? All the grain windmills I have seen have been buildings, but windmills used for other purposes don’t have to be. For example, a man_made=windpump (which just happens to be special cased in OSM) is often not a building.
Many watermills used as saws don’t have a building in my region.


Yes, there are a lot of windmills in Wyoming (US) that ranchers use to pump ground water for livestock (cheaper than running electrical lines to remote areas). These are not buildings and could be described as towers.

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man_made=windmill is for structures that are functionally windmills (operational or historic).
building=windmill is for structures that were built as windmills.

One of the examples on the building=windmill Wiki page (Cragg’s Row Windmill) shows clearly that these tags don’t have a 100% overlap in meaning. Cragg’s Row Windmill no longer functions as a windmill and is therefore not tagged with man_made, but it’s still a building=windmill. By deprecating man_made=windmill you would lose this nuance.

I think windpumps and watermills are off-topic in this conversation. It’s clear that many of those are not buildings, but most or all windmills are buildings.


I have also encountered a few windmills that are not buildings, but rather building parts. Of course I tagged them as building:part=windmill, but if we were to deprecate man_made=windmill in favour of building=windmill, we would lose the relevant feature tag for windmills that are not building=*.

I would like to probe the community about deprecating man_made=windmill and give preference to building=windmill.

I don’t see a problem in keeping both tags, arguably a building made to look like a windmill could get the building=windmill tag, while for a man_made=windmill I would expect it was at least at some point operational, although this may not be the case any more. Some windmills may not qualify as buildings. So if both applies, just tag man_made and building, it’s not an either or.


I don’t see that nuance at all. How does man_made implies use? Not even its wiki states that. The pages are fairly equivalent.
For the type of use, there’s the disused/abandoned/ruins.

Man_made was a scheme created as a catch-all-other-objects-that-dont-fit-elsewhere, but in this case it doesn’t make sense to prefer man_made instead of building.

Can you show me an example of a windmill that doesn’t qualify as building?

As stated before me, a wind pump is not a windmill. They are structurally different and have different purposes.

I’m ok with both windmill being both a building or a building:part. Since there are designed specifically for a large windmill to spin unobstructed. You could eve use a building:part to indicate where the required gears and rotor attachment is. There could even be multiple parts for the various parts of the drive mechanism. The mill, pump or other driven device could be tagged and/mapped separately.

The building tag and other ones such as man_made, amenity etc. have different purposes. The building tag tells you what the building type is, not what it functionally is now. The 2nd paragraph of the building wiki page makes this clear.


what’s your definition of „building“ and of „windmill“?

Isn’t that just an upscaled windpump?

To me (and I’m an old guy, born in the USA’s Midwest) this looks exactly like a thousand other perfectly similar “windmills” of exactly this type across the Midwestern plains of the USA (in the 20th-century and there are plenty of these still around in the 21st). Yes, we call these “windmills,” always have, and I’ve never once even heard (or read) the word “windpump” until just now. Though, I agree “windpump” is a fairly accurate name, given that’s pretty clearly a small water tower on the top of that russet-colored small building.

Honestly, when I hear the word “windmill,” this is the classic example that comes to mind. Though the more “Dutch style” (four, squarish blades closer to the ground on a small building) is a close 2nd place.

3rd place are the more modern, 21st-century versions that harness serious energy to plug into the grid.


I think the OP had something like that in mind, an old style more typical in Europe:


Yeah, now that’s what I call Dutch style!

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Apparently my description was one sentence to short. Yes. I was thinking of buildings like a mill house or those Dutch houses are large wind driven bilge pumps.

There are also those windmills that are mounted on a basic structure. That can include the old rusty one on a small tower pictured above. As well as a those generating electrical using large elongated blades made of carbon filter. All have a fan-like structure that turns wind into kinetic energy.

(found with windmill skeletal image search)

This is not a reliable assumption. One of the problems of man_made= is that it mixes structures, and functions or facilities. This in turns affects building= usage. Eg =kiln and =chimney are structures. historic= is a different aspect with arguably much mess and confusions. disused:man_made= is not correct for structures similar to disused:building= vs disused=yes or alternatives here due to overlapping features. The case of Craggs Row is more about the windmill blade/sail structure having been removed.

That’s true across the range of values of the man_made key as a whole, but with regard to windmills it is possible to separate out operational and non-operational ones by looking at keys other than building first.

As @Friendly_Ghost says above, removing man_made=windmill would remove the ability of maps such as mine to separate out what a building was constructed for, what it was then used for, and whether it is still in use for that second use.

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