tisPlot and
  scatterPlot leave an object named latestPlot in the
  frame from which they were called. tisLegend uses that object
  to set legend arguments (which you can override) and sets reasonable
  defaults for other arguments.tisLegend(..., xrel = 0.1, yrel = 0.1, xjust = 0, yjust = 1, boxType = "n", ncol = 1, cex = 1)legend.
	These can include x and y arguments to position the
	legend, or a list with components named x and y, such alegendbty to legendcex from latestPlot
	and then passed on to legendlegend, with
  class "tisLegend"legend directly.  tisLegend makes things a
  bit easier, however, by using the same argument names as
  tisPlot and scatterPlot to specify color,
  lineType, plotChar and boxType, rather than the
  less intuitive col, lty, pch and bty
  names.  The xrel and yrel arguments provide an
  alternative way to specify legend placement, one that is used by the
  ChartMaker program.legend, tisPlot, scatterPlot