Command Prompt Syntax:

mpiexec -n <number of processes>TWI -slp < slpfile> -sca <scafile > -twi <twifile >

slpfile: input slope file

scafile: input specific catchment area file

twifile: output topographic wetness index file

TopographicWetnessIndex (Input_Specific_Catchment_Area_Grid, Input_Slope_Grid, Input_Number_of_Processes, Output_Wetness_Index_Grid)

Parameter	Explanation	Data Type
Input_Specific_Catchment_Area_Grid	Dialog Reference A grid of specific catchment area which is the contributing area per unit contour length. This should have units of length (area per contour width). It may be the output of the multiple flow direction D-Infinity contributing area function in which case the function by default (without an input weight grid) scales the contributing area in number of cells by the cell size to produce specific catchment area. If D8 or some other contributing area evaluated using the number of cells is used here it should first be scaled by cell size to give specific catchment area in length units. There is no python reference for this parameter.	Raster Layer
Input_Slope_Grid	Dialog Reference A grid of slope. This grid can be generated using ether the "D8 Flow Directions" tool or the "D-Infinity Flow Directions" tool. There is no python reference for this parameter.	Raster Layer
Input_Number_of_Processes	Dialog Reference The number of stripes that the domain will be divided into and the number of MPI parallel processes that will be spawned to evaluate each of the stripes. There is no python reference for this parameter.	Long
Output_Wetness_Index_Grid	Dialog Reference A grid of the natural log of the ratio of specific catchment area (contributing area) to slope, ln(a/S). There is no python reference for this parameter.	Raster Dataset

Topographic Wetness Index

Title Topographic Wetness Index