[Talk-GB] Admin Boundaries and OS OpenData BoundaryLine

[SomeoneElse]

Tom Chance wrote:
> 1) Most boundaries follow existing features like roads, rivers, etc.

That raises an interesting question - how is the boundary actually 
defined?  Is it defined as "the boundary between X and Y is the middle 
of the river Z", or has someone plotted a series of points P 
corresponding to the _current_ course of the river and said "the 
boundary between X and Y is P"?  There are lots of places where 
boundaries (as shown via OS_OpenData_StreetView) don't quite match 
rivers any more - have a look up the River Dove from Ashbourne for an 
example.

If the latter, then clearly the boundary shouldn't share nodes with e.g. 
rivers.

Cheers,
Andy