tpi: Topographic Position Index (tpi)

In jeffreyevans/spatialEco: Spatial Analysis and Modelling Utilities

Topographic Position Index (tpi)

Description

Calculates topographic position using mean deviations

Usage

tpi(x, scale = 3, win = "rectangle", normalize = FALSE, zero.correct = FALSE)

Arguments

x	A terra SpatRaster object
scale	focal window size (n-cell x n-cell for rectangle or distance for circle)
win	Window type. Options are "rectangle" and "circle"
normalize	Apply deviation correction that normalizes to local surface roughness
zero.correct	Apply correction for zero values in matrix weights

Value

A terra SpatRaster object of tpi A terra SpatRaster object

Author(s)

Jeffrey S. Evans <[e-mail]>

References

De Reu, J., J. Bourgeois, M. Bats, A. Zwertvaegher, V. Gelorini, et al., (2014) Application of the topographic position index to heterogeneous landscapes. Geomorphology, 186:39-49.

Examples

library(terra)
elev <- rast(system.file("extdata/elev.tif", package="spatialEco"))

# calculate tpi and plot 
  tpi7 <- tpi(elev, scale=7) 
  tpi025 <- tpi(elev, win = "circle", scale=2500)
  tpi025.zc <- tpi(elev, win = "circle", scale=2500, 
                   zero.correct = TRUE)

opar <- par(no.readonly=TRUE)
    par(mfrow=c(2,2))
      plot(elev, main="original raster")
      plot(tpi7, main="tpi 7x7")
      plot(tpi025, main="tpi Circular window d=2500m")
   plot(tpi025, main="tpi Circular window d=2500m, zero correct")
par(opar)

jeffreyevans/spatialEco documentation built on April 4, 2024, 10:53 a.m.