TraMineR (version 1.4-1)

plot.stslist: Plot method for state sequence objects

Description

This is the plot method for state sequence objects of class stslist created by the seqdef function. It produces a sequence index plot.

Usage

## S3 method for class 'stslist':
plot(x, tlim=NULL, sortv=NULL,
	cpal=NULL, missing.color=NULL,
	ylab, yaxis=TRUE, xaxis=TRUE, xtlab=NULL, cex.plot=1, ...)

Arguments

x

a state sequence object created with the seqdef function.

tlim

indexes of the sequences to be plotted (default value is 1:10), for instance 20:50 to plot sequences 20 to 50, c(2,8,12,25) to plot sequences 2,8,12 and 25 in seqdata. If set to 0, all sequences in seqdata are plotted.

sortv

name of an optional variable used to sort the sequences before plotting.

cpal

alternative color palette to use for the states. If user specified, a vector of colors with number of elements equal to the number of states in the alphabet. By default, the 'cpal' attribute of the 'seqdata' sequence object is used (see

missing.color

alternative color for representing missing values inside the sequences. By default, this color is taken from the "missing.color" attribute of the sequence object being plotted.

ylab

An optional label for the y axis. If set to NA, no label is drawn.

yaxis

Controls whether the y axis is plotted or not. When set to TRUE, sequence indexes are displayed.

xaxis

if TRUE (default), the x (time) axis is plotted.

xtlab

optional labels for the x axis ticks labels. If unspecified, the column names of the 'seqdata' sequence object are used (see seqdef).

cex.plot

expansion factor for setting the size of the font for the axis labels and names. The default value is 1. Values lesser than 1 will reduce the size of the font, values greater than 1 will increase it.

...

arguments to be passed to the plot function or other graphical parameters.

Details

This is the default plot method for state sequence objects (produced by the seqdef function), i.e. objects of class stslist. It produces a sequence index plot, where individual sequences are rendered with stacked bars depicting the statuses over time.

This method is called by the generic seqplot function (if type="i") that produces more sophisticated plots, allowing grouping and automatic display of the states legend. The seqiplot function is a shortcut for calling seqplot with type="i".

The interest of sequence index plots has for instance been stressed by Scherer (2001), Brzinsky-Fay et al. (2006) and Gauthier (2007). Notice that such index plots for thousands of sequences result in very heavy graphic files if they are stored in PDF or POSTSCRIPT format. To reduce the size, we suggest saving the figures in bitmap format by using for instance png instead of postscript or pdf.

Examples

## Defining a sequence object with the data in columns 10 to 25
## (family status from age 15 to 30) in the biofam data set
data(biofam)
biofam.lab <- c("Parent", "Left", "Married", "Left+Marr",
"Child", "Left+Child", "Left+Marr+Child", "Divorced")
biofam.seq <- seqdef(biofam, 10:25, labels=biofam.lab)

## Plot of the 10 most frequent sequences 
## with bar width proportional to the frequency
plot(biofam.seq)

## Plotting the all data set
## with no borders
plot(biofam.seq, tlim=0, space=0, border=NA)