plot.Variogram             package:nlme             R Documentation

Plot a Variogram Object

Description:

     an 'xyplot' of the semi-variogram versus the distances is
     produced. If 'smooth = TRUE', a 'loess' smoother is added to the
     plot. If 'showModel = TRUE' and 'x' includes an '"modelVariog"'
     attribute, the corresponding semi-variogram is added to the plot.

Usage:

     ## S3 method for class 'Variogram':
     plot(x, smooth, showModel, sigma, span, xlab,
          ylab, type, ylim, grid, ...)

Arguments:

       x: an object inheriting from class 'Variogram', consisting of a
          data frame with two columns named 'variog' and 'dist',
          representing the semi-variogram values and the corresponding
          distances. 

  smooth: an optional logical value controlling whether a 'loess'
          smoother should be added to the plot. Defaults to 'TRUE',
          when 'showModel' is 'FALSE'. 

showModel: an optional logical value controlling whether the
          semi-variogram corresponding to an '"modelVariog"' attribute
          of 'x', if any is present, should be added to the plot.
          Defaults to 'TRUE', when the '"modelVariog"' attribute is
          present. 

   sigma: an optional numeric value used as the height of a horizontal
          line displayed in the plot. Can be used to represent the
          process standard deviation. Default is 'NULL', implying that
          no horizontal line is drawn.  

    span: an optional numeric value with the smoothing parameter for
          the 'loess' fit. Default is 0.6. 

xlab,ylab: optional character strings with the x- and y-axis labels.
          Default respectively to '"Distance"' and '"SemiVariogram"'.  

    type: an optional character indicating the type of plot. Defaults
          to '"p"'. 

    ylim: an optional numeric vector with the limits for the y-axis.
          Defaults to 'c(0, max(x$variog))'. 

    grid: an optional logical value indicating whether a grid should be
          added to plot. Default is 'FALSE'.

     ...: optional arguments passed to the Trellis 'xyplot' function.

Value:

     an 'xyplot' Trellis plot.

Author(s):

     Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates
     bates@stat.wisc.edu

See Also:

     'Variogram', 'xyplot', 'loess'

Examples:

     fm1 <- lme(follicles ~ sin(2*pi*Time) + cos(2*pi*Time), Ovary)
     plot(Variogram(fm1, form = ~ Time | Mare, maxDist = 0.7))

