[OSM-talk] All you've ever wanted to know about the french cadastre

[Paul Norman]

> From: Pieren [mailto:pieren3 at gmail.com]
> Subject: Re: [OSM-talk] All you've ever wanted to know about the french
> cadastre
> 
> On Thu, Sep 27, 2012 at 2:18 AM, Paul Norman <penorman at mac.com> wrote:
> 
> > Conclusion:
> >
> > A significant number of cadastre imported buildings consist of
> > multiple ways, such as in the example Frederik gave. The difference
> > from other buildings a week old is statistically significant. This is
> > true even if only looking at the subset of buildings that are new
> buildings.
> >
> > [1]: If anyone doubts this I could carry out an analysis on this
> point.
> 
> Paul, could you repeat your analysis where you distinguish polygons
> tagged "building=yes" and others tagged "building=yes"+"wall=no"
> (which is our tags to identify non-closed constructions like roof,
> balcony, shed) ?

For the changesets identified:

                     Joined   Ways
building=* -wall=*:   12695  17594
building=* wall=no:    6517   6818

I believe the large difference from sets of ways where some are wall=no and
some -wall=* and when combined they simplify farther than either does
separately.