Tool Flow Accumulation (Recursive)

Recursive upward processing of cells for calculation of flow accumulation and related parameters. This set of algorithms processes recursively all upwards connected cells until each cell of the DEM has been processed.

References:

Deterministic 8
- O'Callaghan, J.F. / Mark, D.M. (1984):
'The extraction of drainage networks from digital elevation data',
Computer Vision, Graphics and Image Processing, 28:323-344

Rho 8:
- Fairfield, J. / Leymarie, P. (1991):
'Drainage networks from grid digital elevation models',
Water Resources Research, 27:709-717

Deterministic Infinity:
- Tarboton, D.G. (1997):
'A new method for the determination of flow directions and upslope areas in grid digital elevation models',
Water Resources Research, Vol.33, No.2, p.309-319

Multiple m_Flow Direction:
- Freeman, G.T. (1991):
'Calculating catchment area with divergent flow based on a regular grid',
Computers and Geosciences, 17:413-22

- Quinn, P.F. / Beven, K.J. / Chevallier, P. / Planchon, O. (1991):
'The prediction of hillslope flow paths for distributed hydrological modelling using digital terrain models',
Hydrological Processes, 5:59-79

Author: O.Conrad (c) 2001
Menu: Terrain Analysis|Hydrology|Flow Accumulation

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Elevation	Grid (input)	`ELEVATION`	-	-
	Sink Routes (*)	Grid (optional input)	`SINKROUTE`	-	-
	Weights (*)	Grid (optional input)	`WEIGHTS`	-	-
	Input for Mean over Catchment (*)	Grid (optional input)	`VAL_INPUT`	-	-
	Material for Accumulation (*)	Grid (optional input)	`ACCU_MATERIAL`	-	-
	Accumulation Target	Grid (input)	`ACCU_TARGET`	-	-
	Target Areas (*)	Grid (optional input)	`TARGETS`	-	-
Output	Flow Accumulation	Grid (output)	`FLOW`	-	-
	Mean over Catchment	Grid (output)	`VAL_MEAN`	-	-
	Accumulated Material (*)	Grid (optional output)	`ACCU_TOTAL`	-	-
	Accumulated Material (Left Side) (*)	Grid (optional output)	`ACCU_LEFT`	-	-
	Accumulated Material (Right Side) (*)	Grid (optional output)	`ACCU_RIGHT`	-	-
	Flow Path Length (*)	Grid (optional output)	`FLOW_LENGTH`	average distance that a cell's accumulated flow travelled	-
	Loss through Negative Weights (*)	Grid (optional output)	`WEIGHT_LOSS`	when using weights without support for negative flow: output of the absolute amount of negative flow that occurred	-
Options	Grid system	Grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Step	Integer	`STEP`	-	Minimum: 1 Default: 1
	Flow Accumulation Unit	Choice	`FLOW_UNIT`	-	Available Choices: [0] number of cells [1] cell area Default: 1
	Method	Choice	`METHOD`	-	Available Choices: [0] Deterministic 8 [1] Rho 8 [2] Deterministic Infinity [3] Multiple m_Flow Direction Default: 3
	Convergence	Floating point	`CONVERGENCE`	Convergence factor for Multiple m_Flow Direction Algorithm (Freeman 1991)	Default: 1.100000
	Prevent Negative Flow Accumulation	Boolean	`NO_NEGATIVES`	when using weights: do not transport negative flow, set it to zero instead; useful e.g. when accumulating measures of water balance.	Default: 1
(*) optional

Command-line

Usage: saga_cmd ta_hydrology 1 [-ELEVATION <str>] [-SINKROUTE <str>] [-WEIGHTS <str>] [-FLOW <str>] [-VAL_INPUT <str>] [-VAL_MEAN <str>] [-ACCU_MATERIAL <str>] [-ACCU_TARGET <str>] [-ACCU_TOTAL <str>] [-ACCU_LEFT <str>] [-ACCU_RIGHT <str>] [-STEP <num>] [-FLOW_UNIT <str>] [-TARGETS <str>] [-FLOW_LENGTH <str>] [-METHOD <str>] [-CONVERGENCE <double>] [-NO_NEGATIVES <str>] [-WEIGHT_LOSS <str>]
  -ELEVATION:<str>     	Elevation
	Grid (input)
  -SINKROUTE:<str>     	Sink Routes
	Grid (optional input)
  -WEIGHTS:<str>       	Weights
	Grid (optional input)
  -FLOW:<str>          	Flow Accumulation
	Grid (output)
  -VAL_INPUT:<str>     	Input for Mean over Catchment
	Grid (optional input)
  -VAL_MEAN:<str>      	Mean over Catchment
	Grid (output)
  -ACCU_MATERIAL:<str> 	Material for Accumulation
	Grid (optional input)
  -ACCU_TARGET:<str>   	Accumulation Target
	Grid (input)
  -ACCU_TOTAL:<str>    	Accumulated Material
	Grid (optional output)
  -ACCU_LEFT:<str>     	Accumulated Material (Left Side)
	Grid (optional output)
  -ACCU_RIGHT:<str>    	Accumulated Material (Right Side)
	Grid (optional output)
  -STEP:<num>          	Step
	Integer
	Minimum: 1
	Default: 1
  -FLOW_UNIT:<str>     	Flow Accumulation Unit
	Choice
	Available Choices:
	[0] number of cells
	[1] cell area
	Default: 1
  -TARGETS:<str>       	Target Areas
	Grid (optional input)
  -FLOW_LENGTH:<str>   	Flow Path Length
	Grid (optional output)
  -METHOD:<str>        	Method
	Choice
	Available Choices:
	[0] Deterministic 8
	[1] Rho 8
	[2] Deterministic Infinity
	[3] Multiple m_Flow Direction
	Default: 3
  -CONVERGENCE:<double>	Convergence
	Floating point
	Default: 1.100000
  -NO_NEGATIVES:<str>  	Prevent Negative Flow Accumulation
	Boolean
	Default: 1
  -WEIGHT_LOSS:<str>   	Loss through Negative Weights
	Grid (optional output)