[OSM-talk] Tiles at home Update

Frederik Ramm frederik at remote.org
Tue Mar 20 10:21:16 GMT 2007


> It also utilises a pre-processor (called Frollo) which sorts out the
> ordering and direction of segments.

Hm. Doing everything in XSLT certainly is an interesting programming  
challenge ;-)

I'm curious on how you solved the segment reversal problem. I did an  
automatic way ordering and segment reversal tool in Perl but got into  
trouble when a segment was shared by more than one way:

1. Since I processed the ways one after the other, when I re-visited  
the same segment in the context of a different way, reversing the  
segment (which might have been required for the current way to "work"  
properly) would have meant going back to the other way that used it  
and try if that still works with the segment reveresed. Which seemed  
complicated, especially because the concept is recursive.

2. If there are ways using the same segment, and each one would  
require the segment to be in a different direction, which should  
"win" - or should the segment be duplicated?

3. Same if one way using a segment has a context where segment  
reversal is not allowed (say, a river or a way with oneway=true).  
Another way uses the same segment (e.g. a tram running through the  
one-way street) but would require reversal...


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

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