[FGS] FGS and MrSID support in GDAL

[Frank Warmerdam]

Daniel Morissette wrote:
> As we are working on a new release of FGS, one of the questions that 
> came up once again was whether we could include MrSID support in the 
> build that we distribute on the maptools.org site since the DSDK is not 
> free software as stated in the GDAL format docs at 
> http://gdal.org/frmt_mrsid.html
> 
> Does someone familiar with the MrSID DSDK (FrankW?) know what our 
> options are to include (or not) MrSID in public FGS builds? I know this 
> is a FAQ, but if someone has an answer already that would save me some 
> research.

Daniel,

Redistribution of software based on the MrSID DSDK requires the person
installing the software to be presented with, and agree to some particular
information as I recall.  I'm not sure how this would be accomplished with
the FGS architecture.

Furthermore, as distinctly non-free software, it is incompatible to
distribute the MrSID SDK linked with GPL software.  So some care would
need to be taken to *not* also distribute stuff like the GRASS driver
for GDAL/OGR.  I believe it is also incompatible with the "gpl-like" ecw
license which would require that all other components of the software
(linked at least) be source-available.

My suggestion is to prepare an FGS MrSID plugin but do not manage
it through the normal FGS mechanisms.  Instead offer it off a web page
with the required legal notices.  Let the installer download and place
it in their FGS tree manually.  As long as we explain the issues, and
apply the appropriate notices on the web page I think it then becomes
the end users job to ensure they are complying with the appropriate
licenses.  For the most part (ie. GPL) an end user who does not
redistribute software is allowed to mix proprietary and GPL software
as they wish.  But we, as software providers, are not allowed to do this
for them.

I hope this is helpful.

In the case of OSGeo4W I'm hoping actually have an installer dialog
which explains these issues before letting them proceed with MrSID
driver installation.  But I'm not positive that even that would be
sufficient.  I'm also hopeful that mpg will assist us in ensuring
legitimate approaches (from the lizardtech requirements side of
things) for OSGeo4W and perhaps FGS.

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