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.
Flow routing methods provided by this tool:
- Deterministic 8 (aka D8, O'Callaghan & Mark 1984)
- Rho 8 (Fairfield & Leymarie 1991)
- Multiple Flow Direction (Freeman 1991, Quinn et al. 1991)
- Deterministic Infinity (Tarboton 1997)
References
- Fairfield, J. & Leymarie, P. (1991): Drainage networks from grid digital elevation models. Water Resources Research, 27:709-717. doi:10.1029/90WR02658.
- Freeman, G.T. (1991): Calculating catchment area with divergent flow based on a regular grid. Computers and Geosciences, 17:413-22. doi:10.1016/0098-3004(91)90048-I.
- 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. doi:10.1016/S0734-189X(84)80011-0.
- 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. doi:10.1002/hyp.3360050106.
- 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. doi:10.1029/96WR03137.
- Author: O.Conrad (c) 2001
- Menu: Terrain Analysis|Hydrology|Flow Accumulation|Alternatives
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Elevation | Grid, input | ELEVATION | - | - |
| Sink Routes (*) | Grid, input, optional | SINKROUTE | - | - |
| Weights (*) | Grid, input, optional | WEIGHTS | - | - |
| Input for Mean over Catchment (*) | Grid, input, optional | VAL_INPUT | - | - |
| Material for Accumulation (*) | Grid, input, optional | ACCU_MATERIAL | - | - |
| Accumulation Target | Grid, input | ACCU_TARGET | - | - |
| Target Areas (*) | Grid, input, optional | TARGETS | - | - |
| Output | Flow Accumulation | Grid, output | FLOW | - | - |
| Mean over Catchment | Grid, output | VAL_MEAN | - | - |
| Accumulated Material (*) | Grid, output, optional | ACCU_TOTAL | - | - |
| Accumulated Material (Left Side) (*) | Grid, output, optional | ACCU_LEFT | - | - |
| Accumulated Material (Right Side) (*) | Grid, output, optional | ACCU_RIGHT | - | - |
| Flow Path Length (*) | Grid, output, optional | FLOW_LENGTH | average distance that a cell's accumulated flow travelled | - |
| Loss through Negative Weights (*) | Grid, output, optional | 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 | - | - |
| 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 Flow Direction
Default: 3 |
| Convergence | Floating point | CONVERGENCE | Convergence factor for Multiple Flow Direction Algorithm (Freeman 1991) | Minimum: 0.000000
Default: 1.100000 |
| Contour Length | Boolean | MFD_CONTOUR | Include (pseudo) contour length as additional weighting factor in multiple flow direction routing, reduces flow to diagonal neighbour cells by a factor of 0.71 (s. Quinn et al. 1991 for details). | Default: 0 |
| 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>] [-FLOW_UNIT <str>] [-TARGETS <str>] [-FLOW_LENGTH <str>] [-WEIGHT_LOSS <str>] [-METHOD <str>] [-CONVERGENCE <double>] [-MFD_CONTOUR <str>] [-NO_NEGATIVES <str>]
-ELEVATION:<str> Elevation
Grid, input
-SINKROUTE:<str> Sink Routes
Grid, input, optional
-WEIGHTS:<str> Weights
Grid, input, optional
-FLOW:<str> Flow Accumulation
Grid, output
-VAL_INPUT:<str> Input for Mean over Catchment
Grid, input, optional
-VAL_MEAN:<str> Mean over Catchment
Grid, output
-ACCU_MATERIAL:<str> Material for Accumulation
Grid, input, optional
-ACCU_TARGET:<str> Accumulation Target
Grid, input
-ACCU_TOTAL:<str> Accumulated Material
Grid, output, optional
-ACCU_LEFT:<str> Accumulated Material (Left Side)
Grid, output, optional
-ACCU_RIGHT:<str> Accumulated Material (Right Side)
Grid, output, optional
-FLOW_UNIT:<str> Flow Accumulation Unit
Choice
Available Choices:
[0] number of cells
[1] cell area
Default: 1
-TARGETS:<str> Target Areas
Grid, input, optional
-FLOW_LENGTH:<str> Flow Path Length
Grid, output, optional
-WEIGHT_LOSS:<str> Loss through Negative Weights
Grid, output, optional
-METHOD:<str> Method
Choice
Available Choices:
[0] Deterministic 8
[1] Rho 8
[2] Deterministic Infinity
[3] Multiple Flow Direction
Default: 3
-CONVERGENCE:<double> Convergence
Floating point
Minimum: 0.000000
Default: 1.100000
-MFD_CONTOUR:<str> Contour Length
Boolean
Default: 0
-NO_NEGATIVES:<str> Prevent Negative Flow Accumulation
Boolean
Default: 1