User defined non equidistant contour plots
                                                                
      histogram/file 1 pawhists.hbook                                                                                   
1     VECTOR/CREATE LEVEL(8) R  10 11 12 13 14 15 90 99                                                          
      zone 1 2                                                                                                          
2     CONTOUR 200 8 2 LEVEL                                                                                      
      arrow .8 .75 .5 .54 .2                                                                                            
5     ARROW .8 .75 .5 .44 .2                                                                                     
4     SET CHHE .28                                                                                               
3     ITX .81 .5 '10.0'                                                                                          
      Arrow .5 .32 .1 .28 .2                                                                                            
      Itx .51 .1 '100.0'                                                                                                
      option LOGY                                                                                                       
      h/plot 200 BOX                                                                                                    
6     ARROW .5 .32 .1 .28 .2                                                                                     
6     ITX .51 .1 '100.0'                                                                                         
      close 1                                                                                                           

1. The vector LEVEL contains the list of 8 levels to be drawn.
2. Only the levels specified in the the vector LEVEL are drawn.

   Note also:

3. Some comments can be drawn with the command ITX .
4. The size of the text is in centimeters even if the position is in histogram coordinates (current normalization transformation).
5. The position of the arrow is in the current normalization transformation (here histogram coordinates), but its size is in centimeters (last parameter. Here 0.2).
6. Arrows and text can be drawn in logarithmic coordinates. For lines the logarithm should be computed with SIGMA.