Tool Flow Accumulation (Flow Tracing)
Flow tracing algorithms for calculations of flow accumulation and related parameters. These algorithms trace the flow of each cell in a DEM separately until it finally leaves the DEM or ends in a sink.
The Rho 8 implementation (Fairfield & Leymarie 1991) adopts the original algorithm only for the flow routing and will give quite different results.
References
- Costa-Cabral, M. & Burges, S.J. (1994): Digital Elevation Model Networks (DEMON): a model of flow over hillslopes for computation of contributing and dispersal areas. Water Resources Research, 30:1681-1692. doi:10.1029/93WR03512.
- Fairfield, J. & Leymarie, P. (1991): Drainage networks from grid digital elevation models. Water Resources Research, 27:709-717. doi:10.1029/90WR02658.
- Lea, N.L. (1992): An aspect driven kinematic routing algorithm. In: Parsons, A.J. & Abrahams, A.D. [Eds.], 'Overland Flow: hydraulics and erosion mechanics', London, 147-175. doi:10.1201/b12648.
- 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 | - | - |
| 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 | - | - |
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Step | integer number | STEP | For testing purposes. Only generate flow at cells with step distance (each step row/column). | 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] Rho 8
[1] Kinematic Routing Algorithm
[2] DEMON
Default: 1 |
| Flow Correction | boolean | CORRECT | - | Default: 1 |
| Minimum DQV | floating point number | MINDQV | DEMON - Minimum Drainage Quota Volume (DQV) for traced flow tubes | Minimum: 0.000000
Maximum: 1.000000
Default: 0.000000 |
| (*) optional |
Command-line
Usage: saga_cmd ta_hydrology 2 [-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>] [-METHOD <str>] [-CORRECT <str>] [-MINDQV <double>]
-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
-STEP:<num> Step
integer number
Minimum: 1
Default: 1
-FLOW_UNIT:<str> Flow Accumulation Unit
choice
Available Choices:
[0] number of cells
[1] cell area
Default: 1
-METHOD:<str> Method
choice
Available Choices:
[0] Rho 8
[1] Kinematic Routing Algorithm
[2] DEMON
Default: 1
-CORRECT:<str> Flow Correction
boolean
Default: 1
-MINDQV:<double> Minimum DQV
floating point number
Minimum: 0.000000
Maximum: 1.000000
Default: 0.000000