[OSM-newbies] Why doesn't Mapnik play nice?

Richard Fairhurst richard at systemeD.net
Sun Nov 9 08:43:22 GMT 2008


James Ewen wrote:

> Last month I ripped up a poorly hand laid roadway, and replaced it
> with a GPS trace turned into a way. I waited for the next render
> cycle, and found my nice GPS trace had been turned into a straight
> line between the end points in Mapnik. I double checked things, and
> made sure the way was laid down properly, and waited for another
> render cycle. I then attempted to force a re-render through
> informationfreeway. To date, the way is still a straight line between
> the end points in Mapnik, but if you go into the Potlatch editor, the
> proper way is sitting right there.

It may not necessarily be Mapnik's fault. In the event of freakiness,  
deleted nodes can sometimes get into a way. Some parts of the  
toolchain (Mapnik via osm2pgsql, the /map and /way calls) will ignore  
the deleted nodes. Other parts (Potlatch, the /way/history call) won't.

If this is the case (can't check right now, database is offline) then  
you can just force the nodes to be written by editing the way with  
Potlatch and changing something, so it rewrites the lot.

cheers
Richard




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