Downslope Area
- Author: O.Conrad (c) 2001
- Menu: Terrain Analysis | Hydrology | Flow Accumulation
Description
This interactive tool allows you to specify source cells (with a left mouse click), for which the downslope area shall be identified. For the 'Deterministic Infinity' and 'Multiple Flow Direction' algorithms, which are able to simulate flow divergence, the result will give the percentage of the source cell's flow that drains through each cell.
References
- Bauer, J., Rohdenburg, H. & Bork, H.-R. (1985): Ein Digitales Reliefmodell als Vorraussetzung fuer ein deterministisches Modell der Wasser- und Stoff-Fluesse. Landschaftsgenese und Landschaftsoekologie, H.10, p.1-15.
- 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.
- 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.
- 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.
- 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.
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Elevation | grid, input | ELEVATION | - | - |
| Sink Routes | grid, input, optional | SINKROUTE | - | - |
| Output | Downslope Area | grid, output | AREA | - | - |
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Method | choice | METHOD | - | Available Choices:
[0] Deterministic 8
[1] Rho 8
[2] Braunschweiger Reliefmodell
[3] Deterministic Infinity
[4] Multiple Flow Direction
[5] Multiple Triangular Flow Directon
[6] Multiple Maximum Downslope Gradient Based Flow Directon
[7] Kinematic Routing Algorithm
[8] DEMON
Default: 4 |
| Convergence | floating point number | CONVERGENCE | Convergence factor for Multiple Flow Direction Algorithm (Freeman 1991).
Applies also to the Multiple Triangular Flow Directon Algorithm. | Minimum: 0.001000
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 |
Command Line
Usage: saga_cmd ta_hydrology 5 [-ELEVATION ] [-SINKROUTE ] [-AREA ] [-METHOD ] [-CONVERGENCE ] [-MFD_CONTOUR ]
-ELEVATION: Elevation
grid, input
-SINKROUTE: Sink Routes
grid, input, optional
-AREA: Downslope Area
grid, output
-METHOD: Method
choice
Available Choices:
[0] Deterministic 8
[1] Rho 8
[2] Braunschweiger Reliefmodell
[3] Deterministic Infinity
[4] Multiple Flow Direction
[5] Multiple Triangular Flow Directon
[6] Multiple Maximum Downslope Gradient Based Flow Directon
[7] Kinematic Routing Algorithm
[8] DEMON
Default: 4
-CONVERGENCE: Convergence
floating point number
Minimum: 0.001000
Default: 1.100000
-MFD_CONTOUR: Contour Length
boolean
Default: 0