[Qgis-developer] QGIS Processing Framework

[Martin Dobias]

Hi Camilo

generally I agree with Julien's comments.

I do not fully understand what do you mean with "Module instance serialization".

On Fri, Jul 8, 2011 at 9:04 PM, Camilo Polymeris <cpolymeris at gmail.com> wrote:
>> I agree with your analysis : being able to access the QGis layers for the
>> input/output is now the most important thing to focus on.
>>
>> What precisely is blocking you on this topic ?
>> I saw some recent updates adding a combobox with the layers but did not test
>> it yet. The implementations could handle the conversion into their own
>> internal data structure from the MapLayer objects.
>> I know at least that on the OTB side, a first step will be getting a
>> gdal/ogr compatible dataset name and pass them as input files to the
>> implementation.
>> As I can remember, SAGA has a "gdal/ogr" importer module for inputs, and the
>> output should be simple also as the saga file format is supported by gdal.
>
> Thanks for your comments. The I/O thing is more of a saga-specific
> issue, I am not sure where & in which format to exchange data.. but
> these comments are helping clarify matters.

For me the map layer i/o does not look that hard. In the processing
framework I would directly use the QgsVectorLayer / QgsRasterLayer
instances and pass them to the processing backend. For SAGA backend
the behaviour might be like this:
if the layer data source is directly supported by SAGA, just tell saga
the input file name. If not supported by saga - convert to supported
file type, do the processing and then remove the temporary file(s).
Exporting vector layers can be easily done by QgsVectorFileWriter
class, exporting raster layers may be done using gdal api.

Regards
Martin