Module Upslope Area
This module allows you to specify target cells, for which the upslope contributing area shall be identified. The result will give for each cell the percentage of its flow that reaches the target cell(s).
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
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 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
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This version uses all valid cells (not 'no data' values) of a given target grid to determine the contributing area. In case no target grid is provided as input, the specified x/y coordinates are used as target point.
- Author: (c) 2001 by O.Conrad
- Specification: grid
- Menu: Terrain Analysis|Hydrology|Flow Accumulation
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Target Area (*) | Grid (optional input) | TARGET | - | - |
| Elevation | Grid (input) | ELEVATION | - | - |
| Sink Routes (*) | Grid (optional input) | SINKROUTE | - | - |
| Output | Upslope Area | Grid (output) | AREA | - | - |
| Options | Target X coordinate | Floating point | TARGET_PT_X | The x-coordinate of the target point in world coordinates [map units] | Default: 0.000000 |
| Target Y coordinate | Floating point | TARGET_PT_Y | The y-coordinate of the target point in world coordinates [map units] | Default: 0.000000 |
| Method | Choice | METHOD | - | Available Choices:
[0] Deterministic 8
[1] Deterministic Infinity
[2] Multiple Flow Direction
Default: 2 |
| Convergence | Floating point | CONVERGE | Convergence factor for Multiple Flow Direction algorithm | Minimum: 0.001000
Default: 1.100000 |
| (*) optional |
Command-line
Usage: saga_cmd ta_hydrology 4 [-TARGET <str>] [-TARGET_PT_X <str>] [-TARGET_PT_Y <str>] [-ELEVATION <str>] [-SINKROUTE <str>] [-AREA <str>] [-METHOD <str>] [-CONVERGE <str>]
-TARGET:<str> Target Area
Grid (optional input)
-TARGET_PT_X:<str> Target X coordinate
Floating point
Default: 0.000000
-TARGET_PT_Y:<str> Target Y coordinate
Floating point
Default: 0.000000
-ELEVATION:<str> Elevation
Grid (input)
-SINKROUTE:<str> Sink Routes
Grid (optional input)
-AREA:<str> Upslope Area
Grid (output)
-METHOD:<str> Method
Choice
Available Choices:
[0] Deterministic 8
[1] Deterministic Infinity
[2] Multiple Flow Direction
Default: 2
-CONVERGE:<str> Convergence
Floating point
Minimum: 0.001000
Default: 1.100000