[mapserver-users] Displaying very large shapefiles

[Paul Ramsey]

 What is your data like?
    Are all the shapes of similar size (to within an order 
    of magnitude)?
    Are the shapes spread out homogeneously or heavily clumped into a 
    few areas?
    Are the shapes very very large (many many vertices)?

Maybe you have data which isn't amenable to quadtree indexing. Or maybe
you've exposed a bug :)   

Armin Burger wrote:
> 
> Puneet,
> 
> I tried shptree with parameters from 4 to 10, the effect was always the
> same. The response was quite slow. The index file for a 600000 polygon file
> with 180 MB I use has only 2 MB, so I think the index size for the huge file
> is in a normal range.
> 
> I'm only wondering why an increase in file size and polygon number of about
> 4 times increases the processing time up to 50 times or more. The difference
> between displaying a 600000 and 50000 polygon shapefile however (with
> appropriate zoom level) is neglibile. I don't know if the indexing reaches
> its limits when the amount of shapes is too high.
> 
> Thanks
> 

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     | Paul Ramsey
     | Refractions Research
     | Email: pramsey at refractions.net
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