Separation of buildings and streets - Oxford, UK


I’ve recently started to have more contribution to OSM, now that I have a GPS. I’m mapping mainly Oxford, UK, and there are a few (for me) frustrating things about the map there.

We have quite a few colleges, which have well mappable areas, and there are no problems drawing them. But they are mostly drawn such that the roads have joint edges with the college area. This is really annoying, because there are some cases, when the road is running only along the edge shared with the college - and whenever I click on the edge, I can only edit the college (the area), and never the road…

And even apart from this, it feels much more logical to me, that the roads and the building areas are separate, since they are not really overlapping in reality, just next to each other… Much easier to edit, easier to visualize, easier to handle…

Is there any OSM-wise convention, how to draw these things?
If they should be joined edges, how can one get to the different shared edges, that run between the same nodes? (Like get to the properties of that road, and not to the properties of the area).
If they should be separate, the area has to be deleted and redrawn separately, or is there a method (in JOSM) that separate multiple edges running between the same nodes?

One example area is at 51.7528,-1.2628, where Nuffield College shares the northern edge with “George Street Mews”, as it is shown on the map here, but I cannot get to the road properties anyhow…

It would be great to have general convention, or if there is one already, then to get to know it, so I don't mess up other people's hard work because of my ignorance....


Ben said:For 1. in JOSM click on the double+ way with the middle mouse button, then hold ctrl, and select from the two. You can’t do that in potlatch though.

No… But I would always draw house separately. Areas like small town squares is something I would draw connected, big areas like natural=forest I usually draw disconnected from the lines that it should connect to. IMHO it is a bitch, and not very helpful at all.

If way2 is completely covered by way1 you can select it in potlatch by clicking any shared node and pressing the / key - this will cycle through all ways that share that node.

In JOSM you can middle-click anywhere and a context menu will appear showing you all the objects under the mouse pointer. If you then hold down “ctrl” you can release the middle mouse button without the menu disappearing - all the items in the menu are links, so you can click on way2 and it will be selected.

Fair enough, i can see the point now. Thanks.
Good luck with touchpads, though, which have no middle mouse button…

I tried to look up some examples in popular places, which should have plenty of such structures: (New York, DC, London, Dublin), and it seems that there are usually only buildings, and they are naturally separated. The things that I found similar to the oxford colleges are parks - and I think more of then than not, are separated from the roads - like Hyde Park: big area, separated from the road by gates and fence and walls… On the other hand, Trinity College, Dublin, Ireland is joined with the road…

So, obviously there’s no real consistency just yet…

Wow thanks Socks, I didn’t know that. I’ve been doing ugly stuff to be able to select those kind of ways, now my life just became easier.

There probably never will be… :wink: I know I’m not consistent when I edit stuff so how can everyone be consistent with the tagging o other people?

IMO, areas should reflect what’s on the ground as much as possible, so place their constituent edges and nodes at real-world edges and corners. Highway-ways on the other hand scale with the viewing zoom level, and don’t have defined widths so you can’t for example use the (undefined) outer edge of one to say “this is where the college façade ends and the road’s pavement begins”. From the POV of someone interested in getting areas Right, it makes for bad data: all you can get from the database is that the college wall is somehow in the middle of the road, at the centre-line :-/

Yes, it’s only 10 or 20 metres we’re arguing over, and GPS is accurate to ~10m, but in mediaeval college towns that horizontal distance can make all the difference :slight_smile:

So what do other people do, and what’s their intent when they do that?