DTM — Saturation Grade TWI_DInf

RASTER type data (ESRI GRID format), consisting of square cells of 10 m side. TWI (Topographic wetness Index) expresses the “Saturation Grade” of the slope, calculated at the “Stationary State” calculated by the DInf method calculated on grid No. 45 instead of grid n.10. The stationary state does not imply a “static” situation but a condition “at full speed” in which the water flows along the slope constantly and independently of time. The flow along the side is, on the other hand, imagined as the motion of a “thin film”. The formula is as follows: TWI = Ln(As/tan b), which expresses how soil humidity should increase as the draining area increases (As = draining area) and decrease in inclination (b = Slope). The index is non-dimensional.