[mapserver-users] Displaying very large shapefiles
Paul Ramsey
pramsey at refractions.net
Wed Oct 17 14:44:51 PDT 2001
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
>
--
__
/
| Paul Ramsey
| Refractions Research
| Email: pramsey at refractions.net
| Phone: (250) 885-0632
\_
More information about the MapServer-users
mailing list