Predicting landslides ========================================== Module contributed by Paolo Cavallini - `Faunalia `_ .. note:: This chapter shows how to create an oversimplified model to predict the probability of landslides. First, we calculate slope (choose among various backends; the interested reader can calculate the difference between the outputs): * :menuselection:`GRASS --> r.slope` * :menuselection:`SAGA --> Slope, Aspect, Curvature` * :menuselection:`GDAL Slope` Then we create a model of predicted rainfall, based on the interpolation of rainfall values at meteo stations: * :menuselection:`GRASS --> v.surf.rst` (resolution: 500 m) The probability of a landslide will be very roughly related to both rainfall and slope (of course a real model will use more layers, and appropriate parameters), let's say ``(rainfall * slope )/100``: * :menuselection:`SAGA --> Raster calculator` rain, slope: ``(a*b)/100`` (or: :menuselection:`GRASS --> r.mapcalc`) * then let's calculate what are the municipalities with the greatest predicted risk of rainfall: :menuselection:`SAGA --> Raster statistics with polygons` (the parameters of interest are *Maximum* and *Mean*)