[OpenLayers-Users] Performance

[Vincent Picavet]

Le Mardi 27 Février 2007 18:20, Yves Jacolin a écrit :
> Hi,
Hi Yves,

> I am using OL with a WMS serveur (same layer than the vmap0 WMS from
> metacarta). All this is hosted by a quiet good server. But the 'tiles' take
> some time to be displayed. Do you have some ideas to improve the speed of
> the WMS map displaying ? I am using mapserver cgi to manage my WMS service.

First thing to do is to set the image's format and compression. As for raster 
files like satellite or aerial photographies, if you don't need them to be 
transparent, you should use jpeg and set the compression factor to get a good 
size/quality compromise.

Then you can turn Apache's mod_expires on and add those two variables in your 
apache.conf that concerns your WMS server :

ExpiresActive on
ExpiresDefault "now plus 6 hours"

This will tell the client's browser to keep the images cached instead of 
querying them again when needed.

> I am trying to use TileCache as well to improve this, do you think it is
> the best thing I have to do? I have some problem to set it up, is it the
> good list to have some help?
TileCache is definitely the best way to improve performance with openlayers.
There is a mailing list dedicated to tilecache :
http://openlayers.org/mailman/listinfo/tilecache

I recommend you this very good and newly update information page about 
tilecache :
http://docs.codehaus.org/display/GEOSDOC/TileCache+Tutorial
As for the other questions you may have on this subject, see you on the 
tilecache mailing list :)

Vincent