mrSID conversion on-the-fly

Andreas Albarello andreas.albarello at TERRITORIUMONLINE.COM
Wed Oct 10 17:30:53 EDT 2007

Ben Thompson wrote:
> You may be right, but,
> I initially thought of on-the-fly to avoid the licencing worries and 
> gdal-version-hassles people are posting about.
> The idea is to call the command-line converter gdal_translate somewhere.
> We do have mapscript installed, yes, and Windows.

Seeing that you're talking Windows here and not Unix, I can now relate 
to your fear of recompiling gdal.

I still don't quite get your "licensing worries". Does it matter if 
MrSID is used by gdal_translate or directly by MapServer? I mean, if 
there are licensing problems (I really don't know LizardTech's license 
terms, so I'm of no help here) then they're either way, right?

Anyhow, I believe this is something you should check out: It lists MrSID support as compiled-in. 
That's all you need. You could just take the dlls you need out of that 
package and replace the existing ones in your php folder.

You'll probably need to do that not just with gdal (gdal13.dll or 
gdal14.dll for that matter) but with the other libs as well as some of 
them depend on each other somehow. You might want to use 
DependencyWalker ( to check whether all 
needed dlls are found (starting from php_mapscript.dll) and all function 
imports are available.

Alternatively, you could just replace the existing installation with 
MS4W saving some work and hassle, if that's an option.

Hope this helps.

Best regards,
Andreas Albarello
Analysis & SW Development

Territorium Online srl/GmbH
Via Buozzi/Buozzistraße 12 - I 39100 Bolzano/Bozen
email: andreas.albarello at

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