[Openstreetmap-dev] Data Primatives & schema
immanuel.scholz at gmx.de
Tue Dec 20 19:47:40 GMT 2005
> Following on from my stab last month on a schema, I took on board the
> comments and decided on a different tack. Matt had taken a look at an OSM
> XML schema so I'm kind of feeding off that but focussing on the user end of
> things rather than how the database stores and communicates with users.
/me throws a big cookie at Andy. ;-)
> ZONE: An association of three or more NODEs where the first and last NODEs
> have the same uid.
Not quite right. First, nodes that "have the same uid" ARE the same nodes.
There are no two different nodes with the same uid.
Second, if you want the first and the last node to be the same, you need 4
nodes (which are 3 *different* ones).
The last node is not transfered but implicit the same as the first node.
> 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).
- zones are represented by a clockwise enclose of the area. The last node is
not transfered (its implicit).
- 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
Fine to me.
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