[Qgis-developer] Integrating OSSIM with QGIS

[Tim Sutton]

Hi

On Wed, Jun 8, 2011 at 9:21 PM, Mingjie Su <Su.Ming at geoeye.com> wrote:
> 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.
>

This is a known issue. I have a branch where I have been replacing the
stats routines to use native stats from providers. You can clone it
from here:

https://github.com/timlinux/Quantum-GIS/tree/raster-stats

Its still unstable but maybe you can see where I am heading with this.



> (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?

Currently not, but its an addition that we would love to see. The OTB
folks would appreciate this too.

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

Since we are using GIT now, you can simply fork QGIS, apply your
patches and invite others to test it out. I look forward to doing so
myself.

Regards

Tim

>
> 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----------------------
> --
> Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
> ==============================================
> Please do not email me off-list with technical
> support questions. Using the lists will gain
> more exposure for your issues and the knowledge
> surrounding your issue will be shared with all.
>
> Visit http://linfiniti.com to find out about:
>  * QGIS programming and support services
>  * Mapserver and PostGIS based hosting plans
>  * FOSS Consulting Services
> Skype: timlinux
> Irc: timlinux on #qgis at freenode.net
> ==============================================
>



-- 
Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
==============================================
Please do not email me off-list with technical
support questions. Using the lists will gain
more exposure for your issues and the knowledge
surrounding your issue will be shared with all.

Visit http://linfiniti.com to find out about:
 * QGIS programming and support services
 * Mapserver and PostGIS based hosting plans
 * FOSS Consulting Services
Skype: timlinux
Irc: timlinux on #qgis at freenode.net
==============================================