QGIS SEXTANTE Modeler: Automate yield data processing

This is a followup post to Processing harvest yield data to grid / raster where I outlined my yield data processing steps. This post shows how I use the Modeler in SEXTANTE to automate this process utilising SAGA algorithms.

The idea of the modeler for me is to save time and keep consistent processes. In the screen shot below you can see that the model requires the yield data point file (where the Dry Yield table column needs selecting), paddock boundary and the grid and filtered points output file location. The model takes care of all the processing steps.

Select yield data point file to be processed and choose output location. The modeler does the rest!
Select yield data point file to be processed and choose output location. The modeler does the rest!

While constructing the model the only tricky part was making sure I had a separate ‘Extent’ field to input into the ‘Shapes to Grid’ algorithm. Even though I always leave this blank, it is required for the algorithm to realise the extent is just the minimum covering extent of the input shape file.

SEXTANTE model editing screen displaying input fields and algorithms involved in the yield data processing
SEXTANTE model editing screen displaying input fields and algorithms involved in the yield data processing
Yield Map: L3 Chickpeas 2012
Yield Map: L3 Chickpeas 2012

A few years ago I used to use model builder in ArcGIS and really missed it when I no longer had access to ESRI software. The SEXTANTE Modeler fills that gap and allows a combination of algorithms from several different toolboxes.

Some more advanced applications of Sextante Modeler are available here.

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