[Talk-GB] building shapes from OS Street View

Gregory nomoregrapes at googlemail.com
Mon Apr 5 23:22:52 BST 2010


An example of the StreetView building quality:
http://edgemaster.dev.openstreetmap.org/streetview_tiles/ossv.html?zoom=16&lat=54.76441&lon=-1.58318&layers=BTF
The West side of St Aidan's College curves round, but (as you can see on
OSM) it actually curves with sharp angles so each bedroom still has a flat
wall. It's important to have this local knowledge, I've heard the building
is supposed to be the fingers of God curved round and holding the chapel
that didn't get built in the middle.

But surrounding buildings I could trace. Van Mildert College I lost my GPS
traces for. Durham Business School I'm just too lazy to go around but could
later give it a quick check that OS was correct. Then there are places like
Durham Cathedral (a bit North, across the river) which I don't have access
to walk round the whole perimeter, plus the GPS signal gets terrible against
the tall stone walls.

We are all coming to the same conclusion. This stuff will be great for
tracing where the mapper has local knowledge (or is verifying it, maybe via
a GPS-less friend/relative).

It's like lakes and Yahoo! imagery. I map the paths in a park, but I don't
want to walk across the grass and get the pond outline (possibly along a
muddy/dangerous bank in parts) as it would confuse my traces. Instead I
trace the imagery and align it up to the footpaths I added, knowing at what
sections I went next to the water and where there was an island but tree
cover makes it look connected.


On 5 April 2010 13:28, Richard Bullock <rb357 at cantab.net> wrote:

>
> > I don't think the "we shouldn't sully OSM with OS data" argument stands
> up
> > as looking at my area (Devon) most of the coastline + almost all names of
> > natural features and numerous other stuff has come from the NPE and 1st
> > Edition maps.  The StreetView coastline and waterways data is way better
> > than what we currently have here and unless there is better data coming
> in
> > the near future then we should trace this stuff in asap.
>
> The BoundaryLine dataset should contain the mean-high-water and
> mean-low-water coastlines as vector data.
>
> I wouldn't therefore copy the StreetView raster for coastlines.
>
> If we're going to import any of it, something like the coastlines might
> make
> sense (the original coastlines were largely done via import - and there is
> probably no better source - e.g. even areas with Yahoo imagery will only
> show the coast at one particular snapshot in the tide-cycle).
>
>
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-- 
Gregory
osm at livingwithdragons.com
http://www.livingwithdragons.com
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