Upslope contributing area and wetness index calculation

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Description

Determine upslope contributing area based on an elevation raster and, optionally, compute the topographic wetness index.

Usage

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upslope.area(dem, log = TRUE, atb = FALSE, deg = 0.1, fill.sinks = TRUE)

Arguments

dem

Elevation raster (in m), using a projected coordinate system with identical x and y resolutions.

log

Return the natural log of the values.

atb

If TRUE, include both the upslope contributing area and the topographic wetness index ln(a/tan(beta)). Otherwise calculate just the upslope area.

deg

Minimum intercell slope to identify with a sink (degrees).

fill.sinks

Fill sinks before calculation using the threshold angle given by deg.

Note

This is a wrapper to the function implemented in the TOPMODEL package by Wouter Buytaert.

Author(s)

Peter Metcalfe and Wouter Buytaert

References

Quinn, P. F., Beven, K. J., & Lamb, R. (1995). The In (a/tan/beta) index: How to calculate it and how to use it within the Topmodel framework. Hydrological processes, 9(2), 161-182.

Examples

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## Not run: 
require(dynatopmodel)
data(brompton)

a.atb <- upslope.area(brompton$dem, atb=TRUE)
sp::plot(a.atb, main=c("Upslope area (log(m^2/m))", "TWI log(m^2/m)"))

## End(Not run)