SAGA-GIS Module Library Documentation (v2.1.3)

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.

Parameters

 NameTypeIdentifierDescriptionConstraints
InputTarget Area (*)Grid (optional input)TARGET--
ElevationGrid (input)ELEVATION--
Sink Routes (*)Grid (optional input)SINKROUTE--
OutputUpslope AreaGrid (output)AREA--
OptionsTarget X coordinateFloating pointTARGET_PT_XThe x-coordinate of the target point in world coordinates [map units]Default: 0.000000
Target Y coordinateFloating pointTARGET_PT_YThe y-coordinate of the target point in world coordinates [map units]Default: 0.000000
MethodChoiceMETHOD-Available Choices:
[0] Deterministic 8
[1] Deterministic Infinity
[2] Multiple Flow Direction
Default: 2
ConvergenceFloating pointCONVERGEConvergence factor for Multiple Flow Direction algorithmMinimum: 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