[Openstreetmap-dev] Data Primatives & schema

Matt Amos matt at matt-amos.uklinux.net
Wed Dec 21 00:37:24 GMT 2005

On Tuesday 20 December 2005 19:47, Immanuel Scholz wrote:
> > 1. Are the definitions sufficiently explicit?
> Depends. If you want to implement something depending on this
> definitions, its not enough ;-)
> - nodes are represented by a latitude and longitude value.
> - segments are *ordered* connections.
> - ways are ordered too (from first segment to last).

we have to be more explicit here, i think. the ways must consist of an 
ordered list of segments, where two adjacent segments must share one, 
but only one node and, apart from the first and last, each node must 
be used precisely twice.

example (assume nodes 0-3 are already declared, segments 0-2 go from 
nth to n+1th node):

  <segment uid="0" />
  <segment uid="1" />
  <segment uid="2" />

is legal. however,

  <segment uid="0" />
  <segment uid="2" />
  <segment uid="1" />

is not, as segment 0 is nodes [0,1), segment 2 is nodes [2,3) and they 
don't share a node.

> - zones are represented by a clockwise enclose of the area. The
> last node is not transfered (its implicit).

also, the zone should have a single, non-self-intersecting boundary. i 
know POLYGON supports interior boundaries, but i don't think its 
something we're ready for yet ;-)

> - Is the "keys are objects too" - idea already abandoned? If not,
> you forgot the keys. ;-)
> > 3. Any comments on the nomenclature change of Street to WAY and
> > Area to ZONE
> Fine to me.

"street" and "area" are already implemented and being used, so it 
would be a hassle to change them unless there were a really good 



More information about the dev mailing list