Tool Surface, Gradient and Concentration

Cellular automata are simple computational operators, but despite their simplicity, they allow the simulation of highly complex processes. This tool has been created to apply the concept of cellular automata to simulate diffusion and flow processes in shallow water bodies with in- and outflow, where monitoring data show concentration growth or decrease between the inflow and the outflow points. Parameters are for example nutrients like nitrate, which is reduced by denitrification process inside the water body.
Values of mask grid are expected to be 1 for water area, 2 for inlet, 3 for outlet and 0 for non water.

References:

Heinrich, R. / Conrad, O. (2008): Diffusion, Flow and Concentration Gradient Simulation with SAGA GIS using Cellular Automata Methods. In: Boehner, J. / Blaschke, T. / Montanarella, L. [Eds.]: SAGA - Seconds Out. Hamburger Beitraege zur Physischen Geographie und Landschaftsoekologie, Vol.19, p59-70, online.

Author: R.Heinrich, O.Conrad (c) 2007
Menu: Simulation|Hydrology|Diffusion, Flow and Concentration Gradient Simulation

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Mask	Grid (input)	`MASK`	-	-
Output	Surface	Grid (output)	`SURF`	-	-
	Gradient	Grid (output)	`GRAD`	-	-
	Concentration	Grid (output)	`CONC`	-	-
Options	Grid system	Grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Surface Approximation Threshold	Floating point	`SURF_E`	-	Minimum: 0.000000 Default: 0.001000
	Inlet Concentration	Floating point	`CONC_IN`	-	Minimum: 0.000000 Default: 5.000000
	Outlet Concentration	Floating point	`CONC_OUT`	-	Minimum: 0.000000 Default: 3.000000
	Concentration Approximation Threshold	Floating point	`CONC_E`	-	Minimum: 0.000000 Default: 0.001000
	Minimum Gradient	Floating point	`GRAD_MIN`	-	Minimum: 0.000000 Default: 0.000000
	Neighbourhood	Choice	`NEIGHBOURS`	-	Available Choices: [0] Moore (8) [1] Neumann (4) [2] Optimised Default: 0

Command-line

Usage: saga_cmd sim_hydrology 7 [-MASK <str>] [-SURF <str>] [-GRAD <str>] [-CONC <str>] [-SURF_E <double>] [-CONC_IN <double>] [-CONC_OUT <double>] [-CONC_E <double>] [-GRAD_MIN <double>] [-NEIGHBOURS <str>]
  -MASK:<str>       	Mask
	Grid (input)
  -SURF:<str>       	Surface
	Grid (output)
  -GRAD:<str>       	Gradient
	Grid (output)
  -CONC:<str>       	Concentration
	Grid (output)
  -SURF_E:<double>  	Surface Approximation Threshold
	Floating point
	Minimum: 0.000000
	Default: 0.001000
  -CONC_IN:<double> 	Inlet Concentration
	Floating point
	Minimum: 0.000000
	Default: 5.000000
  -CONC_OUT:<double>	Outlet Concentration
	Floating point
	Minimum: 0.000000
	Default: 3.000000
  -CONC_E:<double>  	Concentration Approximation Threshold
	Floating point
	Minimum: 0.000000
	Default: 0.001000
  -GRAD_MIN:<double>	Minimum Gradient
	Floating point
	Minimum: 0.000000
	Default: 0.000000
  -NEIGHBOURS:<str> 	Neighbourhood
	Choice
	Available Choices:
	[0] Moore (8)
	[1] Neumann (4)
	[2] Optimised
	Default: 0