[OpenLayers-Users] WMS request timeout during zoom/pan/resize

[Heiko Schröter]

Am Dienstag 11 Mai 2010, um 10:37:30 schrieben Sie:

The gridded images are created on special request by mouse clicking a button.

But once this special WMS layer is activated it is handled the same way OpenLayer treats ordinary WMS layers. Once the image is created displaying it is no problem at all.

The generation or "gridding" routine is the expensive procedure.

I cannot see that tiling would help us because it is not the image itself which causes the problem but the generation of it.


Thanks and Regards
Heiko


> Ah, I think I understand.  You could still look into client-side tiling
> though.  The data will still be created on the fly, but it won't make a new
> request every time you pan or resize.
> 
> I assume you're generating your data on the fly because it's frequently
> updated, if so how often?  Is it not possible to use caching, but clear the
> cache every so often?  That might take some strain off your server.
> 
> Jon
> 
> On 11 May 2010 09:30, Heiko Schröter <schroete at iup.physik.uni-bremen.de>wrote:
> 
> > Am Dienstag 11 Mai 2010, um 10:23:51 schrieben Sie:
> > Hi Jon,
> >
> > thanks for your reply. The raster images are so called "gridded" imeges of
> > satellites measurements.
> > They have to be done globally and are created on the fly taken the data
> > points from a PostGIS db.
> >
> > Hence every zoom/pan/resize action triggers the data request and the
> > creation of the "gridded" raster image.
> >
> > That is the reason why i'am trying to delay the creation till the
> > zoom/pan/resize interaction comes to an halt.
> >
> > Thanks and Regards
> > Heiko
> >
> >
> > > Hi Heiko,
> > >
> > > How are you serving your WMS layers?  Can't you just use tiling in
> > > OpenLayers and cache the tiles on the server (like GeoWebCache)?  This
> > > should solve your resizing problems and your slow rendering...
> > >
> > > Jon
> > >
> > > On 11 May 2010 09:10, Heiko Schröter <schroete at iup.physik.uni-bremen.de
> > >wrote:
> > >
> > > > Hello,
> > > >
> > > > we have several WMS Layers some  of which are expensive (in machine
> > cycles)
> > > > to render raster images. We do observe that each time the Browser
> > Window is
> > > > rezised or the user pans/zooms a WMS request is generated for every
> > > > zoom/pan/resize level.
> > > >
> > > > Is there a possibility in OpenLayer to supress the rerendering or the
> > newly
> > > > generated WMS requests till the zoom/pan/resize comes to a halt for
> > certain
> > > > period of time ?
> > > >
> > > > The situation now could bust the server if someone has a nervous hand
> > on
> > > > the mouse ...
> > > >