Particularly in Africa, there are huge number of small round buildings. I believe the best way to model them is with a single node, tagged building=hut; optionally with a radius or width. However, the dominant OSM practice is to use a whole way with lots of nodes. So, I must go along with the community. Unfortunately, I encounter a lot of this while working, for example on #MapLesotho
That's 7 huts, 130 nodes, all the wrong size, some overlapping - likely the result of very bad copy and paste. (There are actually 8 huts there; they missed one.)
My fingers have developed the rhythm for cleaning this sort of thing up in JOSM. First set the simplify-way.max-error to something appropriate (0.3), then for each hut:
- Click to select buliding.
- 'G' to unglue it from the surrounding buildings, if needed.
- Drag to center it correctly.
- Ctrl-Alt-drag to scale it down to the correct size.
- Shift-Y to reduce nodes.
- 'O' to re-round the circle.
Within a few seconds I have this:
8 huts, 86 nodes. It would be probably hard to automate this further without computer vision (because of the manual visual alignment), but using the standard JOSM position of left hand on keyboard, right on mouse, it can go very quickly with the above steps. One possible optimization might be to combine Shift-Y and O into a single keypress i can reach with moving my left hand.
Needless to say, if you are setting up a mapathon for people to map Africa, PLEASE teach them how NOT to make the bad big huts like the above, so I don't have to fix so many thousands of them.