On Mon, Feb 9, 2009 at 1:45 PM, Feargal Hogan (E-mail) < [email protected]> wrote:
> Is there a case for examining the quality of the existing OSM boundary > data and trying to improve it? > Yes. > > Is it worth/possible to create a project to do this, either within the > current OSM framework or without? > Yes, either would be great. > > I'm thinking about something similar to www.mappa-mercia.org, which popped > up on twitter this morning, but with the focus more on a particular dataset > rather than a locale. > > There are a few possible data sources which might help improve the data, > legitimately! > > 1. I wonder if the euro-election constituency boundaries might be available > without any restrictive licences? It might be that the EU would have rights > to such data which would override any OS imposed licencing issues. > > Worth some investigation, although our experience is that the Ordnance Survey's copyright is pretty inviolable > 2. There are lots of physical features from which boundaries are derived - > rivers, roads, etc. Surely if these were mapped as geo-features the data > could be copied to a boundary layer where it was known that the boundary > followed the feature, rather than the other way round. > > Yes, where the boundaries follow a road or river it is relatively easy. > 3. There are lots of "Welcome to Surrey" type signposts around. Mapping > their locations would start to give us some join-the-dots style boundaries. > > Definitely worthwhile. I've derived a lot of boundary points from signs like this. Often the sign is a few metres away from the actual boundary for convenience/safety reasons. But you can often guess that, for example, if there's a sign just before a bridge then the river is the actual boundary. > 4. Lastly, if I drew some crude "from-memory" style boundaries at a very > low zoom level, they could be amended and improved whenever anyone noticed > they were wrong. Would that breach anyone's licencing? > > If you have a photographic memory and used to work for the Ordnance Survey then it might, but otherwise it is reasonable that a person has a working knowledge of their locality. Crude data is much preferable to no data and stepwise refinement is one of OSM's guiding principles. > Just a thought. > > Feargal > > > > OSM does have some administrative boundaries but they are one of the harder > things to derive. > > Some county boundaries can be obtained from old out-of-copyright maps, but > these can and do change over time so it's not an infallable method. > > Borough boundaries have been derived, by some people, in urban areas from > on-the-ground inspection of street furniture (street lights, rubbish bins, > manhole covers, whatever) and then extrapolating from there. > > Ward boundaries are very difficult, I don't know of any general method for > capturing these. > > So, OSM does contain some boundary data, but its not very complete and may > not be very accurate. > > > _______________________________________________ > Mailing list [email protected] > Archive, settings, or unsubscribe: > https://secure.mysociety.org/admin/lists/mailman/listinfo/developers-public >
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