[OSM-talk] Suggestion more complete mapping verifactiion

[tim]

Regarding lists from councils,

often a list of roads names would most likely have been created from
copyrighted data. Even if the road names are facts. Thus, the list of
addresses would be derived data and not suitable for use in OSM. It
reminds me of the state where council surveyors map new roads, but use
OS maps and data, and so the whole map becomes unsuitable for our use.

other sources of addresses - Possibly a shipping company, a catalogue
company, amazon.co.uk ... but would imagine this data would be
commercially sensitive, and not available.

Also, 1950's out of copyright ordnance survey maps, I've used these
for road names before, for areas where I knew hadn't changed much (old
mill workers terraces).

Question: At that time, would royal mail info be under crown
copyright, so perhaps theres a big book somewhere with a list in...

tim

On 9/17/07, Dair Grant <dair at refnum.com> wrote:
> John Baker wrote:
>
> >You give me the list of "official" street names in a given area and I will
> >do the rest.
>
> Aside from the licence issues, the error rates for "official"
> street lists are surprisingly high.
>
> I have almost finished mapping Haywards Heath
> (http://tinyurl.com/2dxh5p), which has a population of 20K and
> covers about 10km^2. Google's map has plenty of errors on it,
> and they buy this data from TeleAtlas (who probably have the
> best commercial road network for the UK).
>
> You can find streets with the wrong name, which are in the wrong
> place, which connect when they shouldn't, are on the map when
> they don't exist, exist but aren't on the map, are mapped as a
> road but are actually a private driveway, etc.
>
>
> I don't think having a "definitive" list of street names for an
> area is going to be as useful as you think, as short of going
> out in person you have no way of knowing how accurate that list is.
>
> I have a geo-tagged photo for every street sign in Haywards
> Heath, but if I sent you those then how would you use that information?
>
> The best you could do is estimate that a lot of street names in
> an empty area of the map probably mean that area is
> under-mapped, but that doesn't actually improve the map.
>
>
> I have no idea how useful it would be in practice, but a better
> way (no licence issues, works outside the UK) to find those
> sparse areas might be to use an image-based technique.
>
> Take some tiles from OSM and another service, recolour then so
> you just have road/background colours, blur a couple of times
> then subtract from each other, and look for large areas where
> there's "stuff" in one map but nothing on the other.
>
> My guess is it won't tell you anything your eye couldn't tell
> you any way, but it might help you identify holes in otherwise
> "complete" areas.
>
>
> -dair
> ___________________________________________________
> dair at refnum.com    http://www.deathvalleycycle.com/
>
>
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