[OSM-dev] Idea about ways / meta-ways

Dave osm at randomjunk.co.uk
Tue Nov 28 09:36:04 GMT 2006


Raphaël Jacquot wrote:
> matthew-osm at newtoncomputing.co.uk wrote:
>
>   
>>   way - ordered list of segments
>>     
>
> this is incorrect though. there's nothing to say the segments are ordered
> for the segments to be ordered we'd need an extra segment_index integer 
> column that would contain the id of the segment in the way, and the 
> primary key on the ways_segments table that would contain (way_id, 
> segment_index)
>
>   
Actually I think it is correct: the version of the schema in SVN has a 
column 'sequence_id'. It's used by the planet import script to order the 
imported segments in a way. And I know from experience that segments in 
ways are definitely ordered -- in a lot of cases the ordering chosen by 
the creator/editors doesn't make much sense, but the ordering does still 
exist.






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