[Qgis-user] Raster data formats

Mon May 18 10:30:53 PDT 2009

Also note that in the gdal discussion thread
that I provided Francesco P. Lovergine  is  advocating for an external
plugin for gdal. That could be another solution.

Agus

Alex Mandel wrote:
> I wonder if we can create an archive like the ubuntu non-free and stick
> a gdal-build in there with at least MrSID support, allowing people to
> optionally replace the one on their system.
>
> Not sure if this get's us out of the legal mess though.
>
> Alex
>
> Agustin Lobo wrote:
>   
>> The problem is, as I understand it, that Juan is not using Windows but
>> Linux. And while
>> ECW&Mrsid support is simply added by
>> the user to the current binary distribution of qgis
>> for windows (i.e., see
>> http://sites.google.com/site/eospansite/qsig-for-windows )
>> getting the same support for qgis installed from binaries for linux is
>> simply impossible.
>> You must go through the much more cumbersome
>> process of
>> (1) Compiling gdal with support for ecw and Mrsid
>> (2) Compiling qgis with that particular gdal
>>
>> Certainly, not a 5 minutes task (in particular for users who just don't
>> even
>> know what compiling means...)
>>
>> So, effectively, regarding qgis, linux users are in disadvantage. Or, in
>> other
>> words, for a regular user of qgis, using windows is better. An astonishing
>> contradiction for gnu software.
>>
>> The roots of the problem are in gdal, it's true. But the branches are in
>> qgis
>> and, after having exchanged messages in the gdal list
>> http://n2.nabble.com/Tickets-2385-and-2683-(ECW-and-MrSID-plugins)-tt2767156.html#none
>>
>> I'm convinced that the problem will not be solved unless the communities
>> behind
>> programs using gdal get involved.
>>
>> Agus
>>
>> Tim Sutton wrote:
>> Hi
>>
>> Alex Mandel wrote:
>>  
>>     
>>>>> Juan Pedro Pérez Alcántara wrote:
>>>>>    
>>>>>           
>>>>>> Hello,
>>>>>>
>>>>>> perhaps this is a silly one, but I'm quite frustrated with conversions
>>>>>> from popular raster formats in the Windows/ArcGIS world to the
>>>>>> Linux/QGIS one. For example, ECW and MrSID are most popular. I think
>>>>>> JPEG2000 should be a good candidate for a raster format in QGIS. As far
>>>>>> as I know, it is fast (piramidized by nature, so to say),
>>>>>> georreferenced, and they work flawlessly and smoothly (my
>>>>>> experience, at
>>>>>> least) in QGIS. Perhaps all of you, much experienced than me for sure,
>>>>>> think that JPEG2000 is not the way and that GeoTIFF or whatever should
>>>>>> do the job. If it is so, I'll stick obviously to that option instead.
>>>>>>
>>>>>> I have been messing around with quite a bunch of libraries to deal with
>>>>>> the conversion. First, there is GDAL, with which I'm able to transform
>>>>>> ECW to almost any GeoTIFF or JPEG that works with QGIS very well, and
>>>>>> with JPEG compression, not so far in size from the ECW source. But then
>>>>>> I tried to use ImageMagick and/or Jasper to convert to JPEG2000, and
>>>>>> here is where I get stuck. I stripped off in gdal_translate the GeoTIFF
>>>>>> tags with BASELINE, but to no avail in ImageMagick, it says always
>>>>>> (with
>>>>>> TIFF, JPEG, etc.) that it cannot write the image. Same with JASPER: I
>>>>>> tried to convert from a gdal_translated jpeg, but without result. What
>>>>>> is that I'm missing? Do you have a proven workflow to do this job?
>>>>>> And with MrSID... not experimented by now, but I tremble only thinking
>>>>>> in that :)
>>>>>>
>>>>>> Perhaps I'm too obsessed with size (file sizes, I mean!!! :) ), and I'm
>>>>>> messing around too much with that subject, when GeoTIFF is providing
>>>>>> good results with a slight size increase. Given the size of hard drives
>>>>>> today (and that I'm not in the massive storage business in the GIS
>>>>>> scene), I think is a fair trade-off for an easy and straightforward
>>>>>> conversion workflow. I'd like very much to hear your opinions about
>>>>>> this.
>>>>>>
>>>>>> Thanks in advance, this is my first post. QGIS is great and thanks
>>>>>> to it
>>>>>> and we have almost left behind the so-called industrial standard in
>>>>>> GIS.
>>>>>> Congratulations for the great job.
>>>>>>
>>>>>> Greetings from Spain,
>>>>>>
>>>>>> Juan Pedro Pérez Alcántara
>>>>>>
>>>>>>       
>>>>>>             
>>>>> I think I'm a little confused, if you have GDAL compiled with ECW and
>>>>> MrSID format these should open in QGIS. Note the most recent version of
>>>>> the windows QGIS standalone is shipping with MrSID support.
>>>>>
>>>>> FYI, the MrSID license is more open, and LizardTech is a sponsor of
>>>>> OSGEO.
>>>>>
>>>>> Alex
>>>>>     
>>>>>           
>> Also note that if you want ECW support in windows builds of QGIS 1.0.2
>> or 1.1.0, you can simply download the ECW dlls from Erdas (by getting
>> the SDK) and place the dlls into the Quantum GIS/bin directory. We could
>> not include them in the installer by default for licensing reasons, but
>> by adding those dlls its pretty easy to get it working.
>>
>> Also note that in my testing the JASPER jp2 raster loading via GDAL is
>> quite slow (frustratingly slow really) on the only real performant way
>> to use a wavelet compressed raster at this stage is to use the Kakadu,
>> Mr Sid or ECW drivers (all of which are proprietary software).
>>
>> Lastly it is probably more appropriate to use gdal_translate to convert
>> between raster formats than imagemagick, since gdal's conversions are
>> 'spatially aware' and will retain all georeferencing etc. data in the
>> image.
>>
>> Regards
>>
>>
>>     
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user
>   
>
>   
>> ------------------------------------------------------------------------
>>     
>
>   
>> _______________________________________________
>> Qgis-user mailing list
>> Qgis-user at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/qgis-user
>>     
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user
>
>   

-------------- next part --------------
A non-text attachment was scrubbed...
Name: alobolistas.vcf
Type: text/x-vcard
Size: 261 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20090518/c9ce4a12/attachment.vcf>