[Talk-GB] building shapes from OS Street View

[Ed Avis]

It appears the choice for buildings is a fight between OS maps, which are likely
derived from high-resolution aerial photos but have been simplified, and the
somewhat lower-resolution photo images available to OSM.  It is not really
possible to survey building shapes on the ground since GPS isn't precise enough,
even if we had enough mappers to walk round the outside of every building.

In London the Yahoo photos are adequate for tracing streets, but trying to get
buildings from them is a bit ropey.  Hence my feeling that the OS data is of
higher quality, even though it's clearly a simplification of the real shape.
But in other, less crowded parts of the country a semi-automated trace from
aerial photos (using the Fuzzer JOSM plugin you mention) might be a better way.

(Indeed, it might be fun to trace the whole country using both methods and then
highlight differences between the two.)

I still believe we could do *something* to get reasonably good building shapes
into the map without waiting for the man-years needed to hand-survey them all.
Even in an area which is not any mapper's particular 'territory'.  The workflow
might be to view the aerial photograph with the OS-traced building shapes on top,
and then either press a button to import the whole area or select individual
shapes.

-- 
Ed Avis <eda at waniasset.com>