Re: [Geotools-gt2-users] very fast postgis rendering

[Wouter S. <wou...@gm...>]

styles:
I'm already using very simple styles, all the colors are websafe, and
i use max 7 different colors...

loose bbox:
i was already using that one, and indeed, it speeded things up, but
never the less, still to slow for a wms server

jdbc settings:
is there any way that i can set this forward only setting? I know only
one place where that parameter is being used, and it's in hibernate...
I don"t find a geotools implementation. Or are you suggesting that i
pull the features in on my own, and create a featurecollection with
it?

datastore cache project:
can't use that one, because it's very important that there are no
caches, the data is a very evolving kind. The application I'm building
is a live wms server for lightnings, and we have a latency of 10
seconds... so 10 seconds after impact, the wms server has to be
updated...

Another challange is that sometimes a large number of points have to
be rendered (over 100 000 points at a time) but these points overlap.
Approximatly 90% of the points aren't visible, there behind other
points. What i could do is write a renderer that takes the spatial
resolution of the image, and render only those points that are
visible... but then there is a deadline...

I haven't yet looked at the uDig renderer, is it in the geotools
codebase, or in the udig trunk? Btw, i'm using 2.4

Finally:
Can't use geoserver either, because i need to render accuracyflags,
and timelines, and creating my own wms server was more easy than
altering geoserver. But i've take a close look at their source :)

thanks!

Wouter Schaubroeck


postgis

On Mon, Apr 21, 2008 at 7:53 AM, Jody Garnett <jod...@gm...> wrote:
> I couple notes off-list because I am at home ....
>  - have a hard look at your styles; there is lots of optimization to gain
> from choosing very simple single color styles
>  - have a look at the various postgis connection parameters; rendering
> *really* speeds up with the "fast bbox parameter" as true ... for details
> check the wiki.
>  - experiment with the jdbc driver settings; I think the forward only rowset
> takes gulps of 200 rows at a time - would more be faster for you?
>  - try out the datastore cache project a SoC student did last year; not sure
> where it is myself...
>  - talk to Andrea Amie; he is the master of speed
>
>  And finally switch to a plugin based renderer like uDig; and code up
> exactly what you need for PostGIS; inline as much code as you need and
> profile, profile profile. This was the approach taken for ShapefileRenderer.
>
>  Finally you are creating a WMS server? Sure you don't just want to download
> GeoServer - it already has support for a range of interesting formats. It is
> modular and you can only include the WMS part if you want ... It is GPL - is
> that a problem for you?
>
>  Cheers
>  Jody
>
>
>  Wouter Schaubroeck wrote:
>
> >
> >
> >
> > Hey list,
> >
> > I'm currently creating a wms server, to render all the lightnings (in
> > a postgis db) in a certain period of time (this is variable, and the
> > user can adjust it). Until now I've used a shapefilerenderer, in
> > combination with the database. Everything works, but if you ask more
> > than 1000 points to render, it gets slow... Now i was wondering if
> > there's a way to improve the speed, if that means reduced
> > functionality, so be it, i just want speed :). Do you guys have any
> > idea how to speed things up? This may be even on the postgis-side...
> >
> > thanks in advance,
> >
> > Wouter Schaubroeck
> >
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