I have been looking at buildings a bit recently, trying to determine whether a house is detached, terraced or semi-detached, by analysing groups of houses. However, a problem is that sometimes buildings are incorrectly joined. One such case that is fairly easy to find is where two buildings are only joined by a single node, and that node is not part of any other building (e.g. cases where three buildings meet at a point would be valid in many cases).
This is almost always incorrect, as two buildings are very unlikely to meet at a single point.
I’ve made a MapRoulette challenge of the cases in County Durham, my area of interest, but can easily do other areas too. All 58000 in the country at once would probably feel too daunting to start, but just 256 in Durham seems doable.
Warning: you will encounter some ugly buildings and may get drawn into fixing other issues, e.g.
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Is this based on Item “0 - overlapping building” in Osmose?
Osmose - Information - overlapping building
Most days, I systematically go through the lists for Ireland and Northern Ireland.
The totals are approximately:
- Ireland 52 (almost all are ‘contrary’ relations)
- Northern Ireland 8 (single user, who doesn’t quite understand the problems of overlapping buildings).
- Wales 3157
- Scotland 2327
- England ~23000
If you can get the group to get the numbers down to under a thousand, perhaps 3 people would be able to maintain it on an ongoing basis.
The issues tend to be generated by established users that are mapping a lot (with issues proportionate to the amount of mapping they do) or new users who also do things like this:
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Not based on that at all, a separate analysis, although there could be some similarities in the results it finds
I don’t tend to look at Osmose at all, but maybe some specific issues like this could be worth it
Yeah, Osmose can be over-whelming and off-putting, but if one concentrates on their own issues and a small number of specific issues, it can be very useful.
So, I randomly found a building in Ireland, which was incorrectly attached with a single node to its neighbour. As this wasn’t showing on the above Osmose search, then your search will find some issues that Osmose won’t.
I hear you loud and clear, you want 9901 issues to fix 
Here you go:
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With a little help, Durham is now done, I can easily generate for other areas, but probably won’t unless I get a request
Is it easy to do? Can you do one centred on Perth, Scotland at map level 13, please?
A slight tweak needed, as I had just been doing it by the geofabrik extract areas, but you probably didn’t want all 4500 for the whole of Scotland. So with just 28 around Perth, here you are:
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By the time I seen it, half of them had been done. And as I was trying to figure out how Map Roulette works the rest were disappearing before my eyes. 
Thanks anyway!
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