[Qgis-developer] QGIS Processing Framework

[cpolymeris at gmail.com]

El , Martin Dobias <wonder.sk at gmail.com> escribió:
> Hi Camilo



> generally I agree with Julien's comments.



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


Storing "presets" (sets of values for parameters). I think this could be  
either by pickling, generating some XML file, or generating python code  
that reconstructs the instance.


> [...]
> 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.


You are right. It seems not too hard. I just wanted to avoid storing files  
(storage space concerns) & was considering ideas like having the possiblity  
of SAGA (or other implementations) tell QGIS which format it prefers or  
understands, so that, say, if one module exports format F and another  
module reads format F, no unnecessary conversion by QGIS is done in between.

But perhaps leave that for later, and now just use the class you mention,  
gdal and ogr.

Thanks for your comments,
Camilo
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