Re: [udig-devel] An update on WMS-C tiles and uDig

[Graham Davis <gdavis@xxxxxxxxxxxxxxx>]

We've been testing against WMS-C compliant servers.  We fetch the tiles 
based on the getCapabilities document that the server returns.  A couple 
of the servers we've tested against are:

http://labs.metacarta.com/wms-c/Basic.py?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetCapabilities&tiled=true
http://www.hectaresbc.org/cgi-bin/tilecache-1.9.prod/tilecache.cgi?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetCapabilities&tiled=true

Graham.


Ugo Taddei wrote:
> Hello Graham,
>
> this is all great news! What servers have you guys tried out? 
> (TileCache? GeoServer/GeoWebCache? Are there others?)
>
> Thanks,
>
> Ugo
>
> Graham Davis wrote:
> > Hi,
> >
> > This is just an update on some of the functionality Emily G. and I 
> > have added to uDig trunk in the last few weeks.  Some of this may be 
> > old news, but it is a quick run-down of the changes we've been making.
> >
> > WMS-C Tile servers are now supported in the catalog and there are 
> > some preferences you can set in regards to this.  On the "WMS-C 
> > Tiles" preferences page you can set the maximum number of concurrent 
> > tile requests (ie: if this is set to 8 it will use a thread pool size 
> > of 8 and only send of a max of 8 tile requests at a time and wait 
> > before sending more), whether to use in-memory cache or on-disk 
> > cache, and you can also set where to cache tiles on disk or choose to 
> > clear the current cache.
> >
> > Additionally, there is an operation that allows you to right-click on 
> > any WMS-C Tile layer in the catalog view and choose to preload all 
> > the tiles for that layer and cache them on disk.  This runs in a 
> > blocking dialog with a progress bar since the layer could potentially 
> > contain hundreds of thousands of tiles and doing so many continuous 
> > requests and disk writing can be resource heavy.  These tile requests 
> > are sent off in groups (default is 16 but this can be tweaked with 
> > the "max concurrent requests" preference mentioned above) and can 
> > take a while.  Beware that the onslaught of so many continuous 
> > requests could potentially bog down the WMS-C server you are loading 
> > the tiles from.
> >
> > There is also a new tiled rendering system that can be used for 
> > rendering any data in uDig.  This can be turned on in the "Rendering" 
> > preference page.  It provides a cleaner flicker-free panning 
> > experience when viewing maps in uDig.  Emily has mentioned this 
> > before via email, but there is also a new Scroll Pan Tool which works 
> > very well when tiled rendering is turned on.  Emily has also cleaned 
> > up the rendering stack a lot, including removing some unnecessary 
> > render events.


--
Graham Davis
Refractions Research Inc.
gdavis@xxxxxxxxxxxxxxx