[Talk-GB] bing image alignment

[OpenStreetmap HADW]

On 10 September 2013 10:09,  <osm at k3v.eu> wrote:

> This has been discussed on the list before. Bing image alignment can be
> quite poor

One unfortunate consequence of this is that there are areas of the map
where the majority of features are out of position by 15 or more feet,
because people have added large numbers of buildings, from Bing,
whilst treating the Bing locations as gospel.

A couple of days ago, I walked a footpath, which turned out, along
with the preceding private road, to be a PROW on foot.  As I wanted to
detail map it to show steps, I first calibrated Bing against OS
StreetView, and moved both the road and path accordingly.  The result
is that it now goes right though the last building to actually be
mapped on the road where the path ends.  Looking at all the,
un-sourced, (another gripe is the amount of material going in with no
source and often no comment, but often quite extensive) buildings in
the area, they seem to align perfectly with uncorrected Bing images.

It is easy to perpetuate such problems by using the existing buildings
to calibrate further additions.

I'm reluctant to correct such bulk errors unless I can find somewhere
to safely sit a GPS for several hours, with a clear view of the sky
and good landmarks on  aerial imagery photographs, to get absolute
proof of the error.  (I don't plan to hire a DGPS receiver!).  Also,
without an explicit source, everything needs carefully checking to
make sure that it is consistent with the same flawed source.

Often the main roads are more accurate in these areas, because they
come from older sources, although I sometimes wonder what those were,
too.