landform

Topographic Position Index (TPI) based landform classification for R.

landform classifies a digital terrain model into slope-position classes (valley, lower slope, flat, middle slope, upper slope, ridge) or into ten landform classes (from canyons to mountain tops), following Weiss (2001) and Jenness (2006). The TPI can be computed over square, circular or annular neighbourhoods, sized in cells or in map units, and standardised over the whole grid (as in the original method) or locally.

Installation

install.packages("landform")

Example

library(landform)

dem <- malta_dtm()

# six-class Slope Position Classification, 9 x 9 cell window
sp <- landform(dem, scale = 9)
sp                  # class areas and percentages
plot(sp, shade = "slope")

# ten-class Landform Classification, circular neighbourhoods of 200 m and 1 km
lf <- landform(dem, class.type = "landform.classification",
               sn = 200, ln = 1000, units = "map", shape = "circle")
plot(lf, what = "area")

See the vignette, vignette("landform"), for a full walk-through.

References

Jenness, J. (2006). Topographic Position Index (tpi_jen.avx) extension for ArcView 3.x, v. 1.2. Jenness Enterprises.

Weiss, A. (2001). Topographic Position and Landforms Analysis. Poster presentation, ESRI User Conference, San Diego, CA.