curvature: Surface curvature

Description Usage Arguments Value Note Author(s) References Examples

View source: R/curvature.R

Description

Calculates McNab's or Bolstad's curvature

Usage

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curvature(x, s = 3, type = "mcnab")

Arguments

x

rasterLayer object

s

Focal window size

type

Method used (mcnab or bolstad)

Value

raster class object of surface curvature

Note

McNab's and Bolstad's variants of the surface curvature (concavity/convexity) index (McNab 1993; Bolstad & Lillesand 1992; McNab 1989). The index is based on features that confine the view from the center of a 3x3 window. In the Bolstad equation, edge correction is addressed be dividing by the radius distance to the outermost cell (36.2m).

Author(s)

Jeffrey S. Evans <[email protected]>

References

Bolstad, P.V., and T.M. Lillesand (1992). Improved classification of forest vegetation in northern Wisconsin through a rule-based combination of soils, terrain, and Landsat TM data. Forest Science. 38(1):5-20. McNab, H.W. (1989). Terrain shape index: quantifying effect of minor landforms on tree height. Forest Science. 35(1):91-104. McNab, H.W. (1993). A topographic index to quantify the effect of mesoscale landform on site productivity. Canadian Journal of Forest Research. 23:1100-1107.

Examples

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  library(raster)
  data(elev)

  m.crv <- curvature(elev, s=5, type="mcnab")
  b.crv <- curvature(elev, s=5, type="bolstad")
    par(mfrow=c(1,2))
      plot(m.crv, main="McNab curvature") 
      plot(b.crv, main="Bolstad curvature")
    

jeffreyevans/spatialEco documentation built on Aug. 11, 2018, 1:08 p.m.