[OSM-talk] osmarender bounding box cropping

[Thom Shannon]

>  > http://wiki.openstreetmap.org/index.php/Osmarender/Options#Bounds
>
> this seems to be an option to the renderer, correct?
>   
yes it is
> clearly there's an architectural issue here that i don't understand yet.
>   
Yes I think that would be a big overhead on the server, the data in an 
osm file is litterally straight out of the database. To clip the ways it 
would have to calculate which ways cross the boundaries of the box and 
create new nodes at the point for the way to stop at, these new nodes 
wouldn't reflect the data in the database, they'd be some kind of 
virtual node.

Another issue is that I dont think a way crossing over the boundary box 
will ever be seen if it has no nodes in the box. For example a long 
stretch of motorway running in a straight line across the corner, the 
two nodes either end of the line may be outside the box. Since it works 
by pulling out all nodes in the area, then finding ways using those 
nodes, then finding other nodes for those ways.

anyone feel free to correct me on all that!
> thanks...
>
> paul
> =---------------------
>  paul fox, pgf at foxharp.boston.ma.us (arlington, ma, where it's 53.6 degrees)
>
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>   

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