topmodel (version 0.7.3)

topidx: Calculation of the topographic index from a DEM raster

Description

Calculation of the topographic index from a DEM raster

Usage

topidx(DEM, resolution, river = NULL)

Arguments

DEM

A matrix representing a digital elevation model with equally sized pixels and equal NS and EW resolution

resolution

Resolution of the digital elevation model (m)

river

A matrix representing a river map (optional). All cells with values higher than 0 will be treated as river cells and are not included in the calculations.

Value

The function returns a list, containing 2 rasters. Atb are the topographic index values of each grid cell. Area contains the contributing area

Details

The river map should not contain negative values

References

See http://paramo.cc.ic.ac.uk/topmodel_tutorial for examples.

See Also

topmodel

Examples

# NOT RUN {
  data(huagrahuma.dem)
  topidx <- topidx(huagrahuma.dem, resolution= 25)$atb
  image(topidx)
# }