Tool Stream Power Index
Calculation of stream power index based on slope and specific catchment area (SCA).
SPI = SCA * tan(Slope)
References
- Moore, I.D., Grayson, R.B., Ladson, A.R. (1991): Digital terrain modelling: a review of hydrogical, geomorphological, and biological applications. Hydrological Processes, Vol.5, No.1
 
- Author: O.Conrad (c) 2003
 
- Menu: Terrain Analysis|Hydrology|Topographic Indices
 
Parameters
|   | Name | Type | Identifier | Description | Constraints | 
| Input | Slope | grid, input | SLOPE | - | - | 
 | Catchment Area | grid, input | AREA | - | - | 
| Output | Stream Power Index | grid, output | SPI | - | - | 
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - | 
 | Area Conversion | choice | CONV | - | Available Choices: [0] no conversion (areas already given as specific catchment area) [1] 1 / cell size (pseudo specific catchment area) Default: 0 | 
Command-line
Usage: saga_cmd ta_hydrology 21 [-SLOPE <str>] [-AREA <str>] [-SPI <str>] [-CONV <str>]
  -SLOPE:<str>	Slope
	grid, input
  -AREA:<str> 	Catchment Area
	grid, input
  -SPI:<str>  	Stream Power Index
	grid, output
  -CONV:<str> 	Area Conversion
	choice
	Available Choices:
	[0] no conversion (areas already given as specific catchment area)
	[1] 1 / cell size (pseudo specific catchment area)
	Default: 0