compare.matrix: Biplot Comparison of Matrices

In SDMTools: Species Distribution Modelling Tools: Tools for processing data associated with species distribution modelling exercises

Description

compare.matrix compares the values within two matrices (e.g., ESRI ArcInfo ASCII raster files) and produces a biplot that shows the frequency of each data combination shared between the matrices. The plot is overlayed with contour lines that demarcate parts of the the plot that share the same frequency of data combinations.

NOTE: it is assumed the matrices are of the same extent, cell size and scaled to be the same units.

Usage

compare.matrix(x, y, nbins, ...)

Arguments

x	a matrix of data; the matrix can be a raster of class 'asc' (adehabitat package), 'RasterLayer' (raster package) or 'SpatialGridDataFrame' (sp package)
y	a matrix of data of the same extent, cell size and class as 'x'
nbins	number of equally spaced bins used to partition range of values in 'x' & 'y'
...	other graphical parameters defined by image(), contour(), or plot()

Value

Nothing is returned but images are created.

Author(s)

Luke Shoo [e-mail]

Examples

#create some simple objects of class 'asc'
tasc = as.asc(matrix(rep(x=1:10, times=1000),nr=100)); print(tasc)
#modify the asc objects so that they are slightly different
tasc1 = tasc + runif(n = 10000, min = -1, max = 1)
tasc2 = tasc + rnorm(n = 10000, mean = 1, sd = 1)

#create some images
#basic plot showing the density of data combinations shared
#by the two matrices
compare.matrix(tasc1,tasc2,20)

#same as previous but with data partioned amoung more bins
compare.matrix(tasc1,tasc2,50)

#same as previous but altering the number of contour levels
#and adding more graphical functions
compare.matrix(tasc1,tasc2,50,nlevels=5, xlab='asc1',ylab='asc2',
  main='Comparison between asc and asc2', bg="grey")

Example output

Raster map of class "asc":
Cell size:  1 
Number of rows:  100 
Number of columns:  100 
Type:  numeric 

SDMTools documentation built on Jan. 11, 2020, 9:23 a.m.