[talk-ph] to share or not to share nodes?

maning sambale emmanuel.sambale at gmail.com
Tue Apr 27 10:33:39 BST 2010


I'm posting this inquiry to gather best practices when editing nodes
and ways.  Basically, OSM data are composed of two data primitives:
nodes (points, vertices) and ways (lines and polygons).  Relations are
special type of ways and nodes.  The data model allows for sharing
nodes/ways with different tags.  For example, a node can be part of a
highway, traffic_signals can be added to node which is part of a
highway way.

However, in many cases it is good editing practice to minimize node
sharing.  Partly for ease of editing and partly to avoid routing
errors (especially for highway ways).  Here's a list of editing
practices I will use from hereon in order to avoid node sharing
problems mentioned above.  Please add or delete anything in the list.

1. Highways should not share nodes with other non-highway related ways
(such as administrative boundaries, landuse, building outlines)
2. Nodes for adjacent landuse types can share nodes.
3. Administrative boundaries should be in relations not as shared nodes/ways.
4. Natural and landuse ways can share nodes.  For example,
natural=water (for lakes) can share nodes with landuse=farm.
5.  Admin boundaries should not share nodes with landuse.  Landuse
change more often than admin boundaries.
6.  add more here ...

"Freedom is still the most radical idea of all" -N.Branden
wiki: http://esambale.wikispaces.com/
blog: http://epsg4253.wordpress.com/

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