What's the best OUTPUTFORMAT for ECW-files using WMS

[Steven De Vriendt]

Ok, back to square one then...I assumed that splitting my
image up in several tiles would speed things up but
with this info it seems like I'll have to get the best out of serving the
original file (±390 meg).

On a side note, are WMS-images delivered on the same way like f.i.
google maps, earth do that or should I say is Google Earth some sort
of great WMS-client...sorry if this is not relevant to the original
question, though it's interesting to know.

Thanks to all for your usefull info !

Steven


On 4/23/07, Frank Warmerdam <warmerdam at pobox.com> wrote:
> Steven De Vriendt wrote:
> > I have about 50 ECW-files which I like
> > to serve via WMS.
> >
> > I'm using following OUTPUTFORMAT:
> >
> > OUTPUTFORMAT
> > NAME PNG24
> > DRIVER "GD/PNG"
> > MIMETYPE "image/png"
> > EXTENSION PNG
> > FORMATOPTION "INTERLACE=OFF"
> > IMAGEMODE RGBA
> > TRANSPARENT ON
> > END
> >
> > Image quality is good, but the performance is not what I'd like it to be.
> > Can anyone help me adjusting these parameters ?
>
> Steven,
>
> On issue is of course whether it is really the input or output that is
> slowing things down.  PNG24 output is generally quite expensive computationally
> and folks have often found JPEG better for 24bit output.  JPEG also produces
> much smaller files which is generally good.
>
> I'd add that each ECW that has to be opened and any imagery read from will
> be expensive.  If you can it is better with ECW to make a single large
> mosaic unless you know that views are constrained in such a way that allmost
> all requests will only touch one file.
>
> Best regards,
> --
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | President OSGeo, http://osgeo.org
>
>