[Mapserver-users] Mapserver performance for large maps -
armin.burger at gmx.net
Wed Jul 28 18:13:13 EDT 2004
I would regard the basic requirements for fast map display as
- create spatial index for shapefiles using shptree tool
- display layer only for scale ranges that make sense
This way it's easily possible to server layers based on shapefiles with some hundreds of MB and/or some 100000 features.
For very large datasets keeping shapefiles separate might be a bit faster, but this depends also on the data structure
In my impression PostGIS is not very much slower than shapefiles, at least not for resonable relations scale-detail. If you work with filter statements they can even be faster because you can set indexes on the filter item for the PG table. And if you use attribute search PostGIS is much faster (using indexes) and more flexible than shapefiles.
Very big datasets become difficult for shapefiles, say, something like some millions features and some GB file size. PostGIS tables can handle these huge datasets much better.
> I'm installing and configuring Mapserver for use in a geo-located photo
> album. I'm currently converting the vmap0 maps from their format into
> shapefiles with ogr2ogr so I can use them, and have a few questions
> about how to obtain the best performance:
> - Should I merge all 4 regions of a particular layer into one file, or
> is there a benifit to keeping them seperate?
> - Am I likely to encounter performance issues with such large layers?
> (The largest will be ~500MB - though I may not use it - the average
> probably around 30-60MB) If so, how can I improve performance? I'm aware
> I should have lower detail maps for wider views, but what can I do
> beyond that?
> - Will loading the maps into PostGIS give an improvement in performance?
> I'd read somewhere that shapefiles are slightly faster than postgis for
> simple geographical queries - is this the case for large amounts of data
> such as this?
> - What other things can I do to improve performance considering the
> amount of accessible map data?
> Nick Johnson
> Mapserver-users mailing list
> Mapserver-users at lists.gis.umn.edu
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