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

[Frank Warmerdam]

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,
-- 
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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