[GRASS-user] File formats in r.in.gdal

[Frank Warmerdam]

nicholas.g.lawrence at mainroads.qld.gov.au wrote:
>> Tim Bowden said :
>>
>> The ecw lib has never been offered under a true open source license.
>> The old license allowed "open source GPL style" use for non commercial
>> use only.  The new license is much more restrictive in some ways.
>> Certainly gdal can be compiled against the old ecw code.  I'm not sure
>> about the latest ecw lib releases.  Either way it's up to you to
>> determine your licence rights.  Beware the old license is inconsistent,
>> vague, internally contradictory and generally doesn't parse well.  FWIW,
>> I believe it's worth trying to avoid depending on ecw if this is an
>> issue for you.  Having said that, avoiding ecw may well not be a viable
>> option, in which case you may have to look at a commercial license for
>> it.
> 
> My understanding is that ecw and jpeg2000 share some compression
> technology. Is jpeg2000 a viable replacement for ecw? Are the
> liscencing conditions for jpeg2000 more favourable for
> open source?

Nick,

JPEG2000 fills a similar role to ECW (or MrSID) - a lossy high compression
format.  There are several implementations of JPEG2000 (as opposed to only
one I know for ECW) which is good.  One or two are true open source including
the JasPer library which is used in the GDAL JPEG2000 driver.  There are
also three other GDAL JPEG2000 drivers based on proprietary libraries.
They are the MrSID SDK, the ECW SDK and the Kakadu library (JP2MRSID,
JP2ECW and JP2KAK drivers respectively).

Unfortunately the JasPer library is not suitable for large geospatial
images because it assumes the whole image can be decoded in memory.  So
this is only useful if you work with very modest sized images.

This leaves us, for the time being, in the position where there is no
good GDAL JPEG2000 driver that is truely open source.  However, at least
you have more options with JPEG2000.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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