Panel function for drawing lines as part of a circle centred in (0, 0) into a trellis graphic (lattice
  package).
     
    
    Usage
    adeg.panel.join(drawLines, params = list())
 
     
    
    Arguments
    
- drawLines
 
a vector containing the level values used as radius of the circle
 
  - params
 
graphical parameters : plabels and add.line (lattice)
 
 
    
    Value
    Displays level lines and their values.
     
    
    
    Note
    For more information about the use of panel functions, please see the lattice package developed by Deepayan Sarkar.
     
    
    Examples
    if(require(lattice, quietly = TRUE)) {
  xyplot(0:20 ~ 0:20, drawLines = c(5, 10, 15), params = list(plabels.cex = 2), 
    panel = function(drawLines, params){
      adeg.panel.join(drawLines = drawLines, params = params)})
}