- data
 
A data.frame containing labels, grid.x, 
             grid.y and, if specified, colour.column.
 
- labels
 
A character giving the name of the column in 
               data containing the labels to be plotted on the grid.
 
- grid.x
 
A character giving the name of the column in data that 
               specifies the x-coordinates of the plot grid.
 
- grid.y
 
A character giving the name of the column in data that 
               specifies the y-coordinates of the plot grid.
 
- reverse.x
 
A logical which, if true, causes the order of values on the 
              x-axis to be reversed.
 
- reverse.y
 
A logical which, if true, causes the order of values on the 
              y-axis to be reversed.
 
- colour.column
 
A character giving the name of the column in data that 
               is to be used to colour the values plotted on the grid.
 
- colour.values
 
A character giving the name of the column in data that 
               is to be used to colour the values plotted on the grid.
 
- xlab
 
Label for the x-axis. By default it is the name of the
             grid.x.
 
- ylab
 
Label for the y-axis. By default it is the name of the
             grid.y.
 
- title
 
Title for plot window. By default it is "Plot of labels".
 
- printPlot
 
A logical indicating whether to print the plot.
 
- ggplotFuncs
 
A list, each element of which contains the 
                results of evaluating a ggplot2 function. 
                It is created by calling the list function with 
                a ggplot2 function call for each element.
                These functions are applied in creating the ggplot object.
 
- ...
 
Other arguments that are passed down to the geom_text call that plots the labels.