[OSM-dev] Suggestion about design of OSM data structure

[Frederik Ramm]

Chien,

    it is well known and long discussed that removing segments will  
make things easier.

You are, however, slightly underestimating the complexity of the  
task, because of two reasons:

1. Currently, we can have branching ways (e.g. Y-shaped). These need  
to be split into several ways when we remove segments. This is  
possible but probably difficult to automate fully (e.g. if you have a  
main road with lots of little branches, you want the branches to be  
split off and the main road to remain in one piece!).

2. Currently, we can have non-contiguous ways, which are sometimes  
used to model "areas with holes" (say you have a forest with a  
clearing, then the forest will be one "ring" with clockwise segments  
and the clearing another "ring" with anticlockwise segments and both  
joined into one way). You cannot model this with simple ways alone;  
another way would have to be found for areas with holes in them.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'