[Qgis-developer] Integrating OSSIM with QGIS

[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----------------------
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