On Wed, Dec 12, 2018 at 06:10:24PM +0000, Rick Bowlby wrote: > Hello, I quite recently imported Ordnance Survey Boundary-Line data > (October 2018, OGL v3) for recently changed electoral wards in > Manchester (changeset > 65101926 <https://www.openstreetmap.org/changeset/65101926>). I hope this > isn't controversial - these boundaries are useful to me and potentially > others as well, and I understand that the OGL is compatible with OSM. > > But I've now noticed that the outer boundary of the wards is not coincident > with the current administrative boundary for Manchester City Council in OSM > (relation 146656 <https://www.openstreetmap.org/relation/146656>) - as far > as I can see, the discrepancies are up to about 5m or so. However it is > consistent with the city boundary in the same OS dataset. The sources for > the existing OSM data seem to be mixed - there are references to Ordnance > Survey sources (without dates), in some places the boundary ways are > rivers, there are also references to the "historic course" of a river and > so on.
This is perhaps slightly off topic, but this habit of some of sharing nodes causes me many problems. When I am updating roads and other features from fairly accurate gps surveys, I often find the I have all these tangled boundaries about which I know little. It is a huge pain to duplicate nodes to separate ways before I can adjust just the feature that I have surveyed. I confess that my patience often runs out, and I just drag the other stuff along with my updates, thinking that the mappers who shared the nodes in the first place get what they deserve :-). So I may be responsible indirectly for some minor inaccuracies of certain boundaries, although nowhere near Manchester. I am normally extremely respectful of other mappers' work, but this is one area where I find that it is just too difficult to avoid possible minor damage. Maybe I just haven't found the right tools. ael _______________________________________________ Talk-GB mailing list Talk-GB@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-gb
