StreamOrder: network of cells with accumulation at least
threshold, Strahler (1957) or Shreve (1966) order.
TopographicWetnessIndex: \(\ln(a/\tan\beta)\) (Beven and Kirkby
1979); StreamPowerIndex: \(a\tan\beta\) (Moore et al. 1991),
\(a\) the accumulated cells times res.
Usage
StreamOrder(flowdir, acc, threshold, method = "strahler")
TopographicWetnessIndex(acc, slope, res = 1, min_slope = 1e-06)
StreamPowerIndex(acc, slope, res = 1)
Arguments
- flowdir
D8 codes.
- acc
Accumulation.
- threshold
Network threshold.
- method
"strahler" or "shreve".
- slope
Slope (radians).
- res
Cell size.
- min_slope
Slope floor.
References
Strahler, A. N. (1957). Quantitative analysis of watershed
geomorphology. Transactions, American Geophysical Union 38, 913-920.
Beven, K. J. and Kirkby, M. J. (1979). A physically based, variable
contributing area model of basin hydrology. Hydrological Sciences
Bulletin 24, 43-69.
Examples
fd <- rbind(c(2, 4, 8), c(0, 4, 0), c(0, 0, 0))
StreamOrder(fd, FlowAccumulation(fd), 1)
#> [,1] [,2] [,3]
#> [1,] 1 1 1
#> [2,] 1 2 1
#> [3,] 1 2 1
TopographicWetnessIndex(matrix(4), matrix(atan(0.5)), res = 2)
#> [,1]
#> [1,] 2.772589
