[Qgis-developer] QGIS Processing Framework

[Martin Dobias]

Hi Soeren

On Thu, Apr 28, 2011 at 3:36 PM, Soeren Gebbert
<soerengebbert at googlemail.com> wrote:
> A lot of work has been done to integrate these GIS packages as web
> processing service back-ends, so you can use them out of the box and
> avoid redundant implementations of the same idea.
>
> The support of the OGC WPS standard in QGIS will allow you to:
> - use open standards for interface descriptions
> - Integrate the existing WPS server and there processes (~400?) as
> algorithms into QGIS
> - chain/orchestrate WPS processes from different back-ends
> - directly integrate WFS and WCS sources as inputs without the need of
> local storage
> - Working with QGIS on a silent and long running computer in the
> office while the processing is done on a heavy and fast server in the
> basement

I agree that all these are very good reasons for having WPS support in
QGIS. It makes sense in a lot of use cases. Still I do not think we
should concentrate exclusively on WPS services for processing for
several reasons:
- the community creates lots of handy plugins, many of them are used
for processing. It is not just SAGA, OTB, GRASS or OSSIM that could
use the framework - we are speaking about many more possible modules
that probably will never be implemented as WPS services.
- WPS servers are IMHO not really widespread yet(?). Surely you can
install your own on a local computer but I don't think that an average
user is able to manage it with few clicks. And not everyone has access
to a fast server in basement.
- usability matters - a lot of work can be done by only editing few
parameters and running the process, but there are plenty of cases
where more interactivity is desired as mentioned also by Julien and
Camilo: that could be a complex dependency between input parameters or
a possibility for interactive picking of points from map canvas.

The reasons above make me believe that we shouldn't depend exclusively
on WPS. In my vision WPS should be simply another provider of
processing modules next to SAGA, OTB or various other smaller plugins.
WPS itself simply cannot deliver the rich user interface that we would
like to provide.


Regards
Martin