Poor Mr. SID image performance as a layer

[Frank Warmerdam]

On Thu, 17 Feb 2005 14:52:48 -0600, Brian Fischer
<bfischer at houstonengineeringinc.com> wrote:
>
> Are there any tips or tricks to get better performance with Mr. SID images
> or am I out of luck with these large Mr. SID files?  I am using the binary
> from Hobu's kitchen sink MapServer 4.4.1
> (http://hobu.stat.iastate.edu/mapserver/).
>
> I am using a 320mb Mr. SID image as a raster layer and it is taking about 30
> seconds for MapServer to refresh my map.

Brian,

I have dramatically reworked the GDAL MrSID driver and with the
latest code you should see good (though not really great) speed.

I have a 370MB MrSID RGB file and am seeing roughly 2 second
turn around time on my Athlon 1800 system.  Performance should
be even better on greyscale files.

The code is committed in CVS and should be in last nights CVS
snapshot for GDAL.  It is *not* in 1.2.5.  I hope to release a GDAL
1.2.6 early next week.

I would like to stress that the poor performance was due to a
"simple" design in the old MrSID driver in GDAL, not due to problems
with the underlying MrSID technology.

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    | Geospatial Programmer for Rent