[Qgis-developer] Integrating OSSIM with QGIS

[Marco Hugentobler]

Hi Ming

This sounds interesting. What dependencies on external libraries does the 
provider have?

> (5) Can we post our ossim image provider to your svn for others to play
> with?

QGIS switched to git in the meantime. You could clone the QGIS repository 
(git at github.com:qgis/Quantum-GIS.git) and upload the changes to the cloned 
repo. Or just provide a patch against current master branch.

> (1) Is there a way for users to specify which provider to use? It looks
> like QGIS is hard coded to use the GDAL provider.

This needs changes in the GUI. If it is only about file based datasources, it 
is a possibility to add a combo box to the 'add rasterlayer' dialog. 

If database / web services should also be accessed, it might be necessary to 
add a new dialog.

Regards,
Marco  

Am Mittwoch, 8. Juni 2011, 21.21:05 schrieb Mingjie Su:
> All-
>    We are making some good progress on the ossim image provider
> (qgsossimprovider.cpp). Couple questions:
> 
> (1) Is there a way for users to specify which provider to use? It looks
> like QGIS is hard coded to use the GDAL provider.
> 
> (2) Band statistics. QGIS is pretty inefficient when it comes to computing
> band statistics. Its looping through all the pixels multiple times (once
> for each band) to populate the viewport. For RGB data for example, its
> looping through the data 3 times. In OSSIM, we can provide the band
> statistics for you so you don't have to scan the data. This will speed
> things up dramatically. BTW, this is true for both the GDAL and OSSIM
> providers.
> 
> (3) Black pixels (0,0,0 RGB) are being flipped to transparent. Is there a
> way to override this behavior programatically?
> 
> (4) In OSSIM we have a concept of image chains and connectable objects. You
> can wire up all kinds of filters and equations into a workflow to create
> an output image. The image chain can be represented using an array of key
> value pairs. Does the provider interface provide a mechanism for passing
> this type of information?
> 
> (5) Can we post our ossim image provider to your svn for others to play
> with?
> 
> 
> Thanks,
> Ming
> 
> 
> 
> -----Original Message-----
> From: Peter Borissow
> Sent: Wednesday, May 25, 2011 4:08 PM
> To: Tim Sutton; Pirmin Kalberer
> Cc: qgis-developer at lists.osgeo.org; qgis-ossim at lists.sourceforge.net;
> Mingjie Su; Harsh Govind Subject: RE: [Qgis-developer] Integrating OSSIM
> with QGIS
> 
> Hi Tim-
>    We are playing with 1.6. We'll download the 1.7 branch right away. I
> agree, use of gdal should be abstracted away into a gdal provider. Sounds
> like we would create an OSSIM provider.
> 
> And yes, we want to create/execute OSSIM image chains directly in QGIS!
> 
> Thanks,
> Peter
> 
> 
> 
> -----Original Message-----
> From: Tim Sutton [mailto:lists at linfiniti.com]
> Sent: Wednesday, May 25, 2011 4:03 PM
> To: Pirmin Kalberer
> Cc: qgis-developer at lists.osgeo.org; Peter Borissow;
> qgis-ossim at lists.sourceforge.net; Mingjie Su; Harsh Govind Subject: Re:
> [Qgis-developer] Integrating OSSIM with QGIS
> 
> Hi Peter
> 
> 8<-------------------snip----------------------
> 
> >> > We started our investigation late last week. We have a debug version
> >> > of QGIS up and running in Visual Studio 10 (64 bit) using QT 4.7.3. We
> >> > have since discovered how integral GDAL is to QGIS. Undaunted, we
> >> > added a some temporary hacks to bypass GDAL and we're now getting
> >> > images to display via OSSIM! For us, this is a huge first step and we
> >> > are seriously considering pressing ahead.
> 
> What version are you building against? Since the 1.7 branch and in
> current master branch, Radim Blazek has done a great overhaul to cater
> for proper raster providers. That means you should not find QGIS is
> heavily intertwined with GDAL - the use of gdal should be abstracted
> away into the gdal provider, and you should be able to implement ossim
> raster support as a clean separate provider.
> 
> I would also really love to see OSSIM support in QGIS (and maybe some
> of those nice processing chains making their way into QGIS :-).
> 
> Regards
> 
> Tim
> 
> 8<-------------------snip----------------------


-- 
Dr. Marco Hugentobler
Sourcepole -  Linux & Open Source Solutions
Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee