[OSM-dev] Best way to select from a region

Stephan Knauss osm at stephans-server.de
Tue Sep 1 21:23:39 BST 2009


Roland Olbricht wrote:
> http://wiki.openstreetmap.org/wiki/OSM_Server_Side_Script
that sounds cool. Did not know it before. It's not advertised a lot ;)
What are the limits? Frederik mentioned a query against a polygon might 
be slow. Which area could be returned? Only a city? Bavaria? France?

I don't want to use xapi. The area can only be described by a bounding 
box. I even feel the poly files available at cloudmade are too 
inaccurate. In some places they are off by a huge distance.
And interesting places often tend to be near borders that mark boundaries.

Has someone already implemented a way to view those .poly files in 
openlayers? Could help to determine which areas are affected.

I also thought about maybe using a rectangular box to update the data 
and from time to time use the expensive polygon match to "blacklist" 
nodes outside the polygon. Those could be subtracted from the box.
Assuming not much changes in those areas the number of false matches 
might be low.

Or maybe only query the nodes near the border against the expensive polygon?

Stephan




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