static public GraphDesc getGd() {
GraphDesc gd = new GraphDesc();
gd.add("sun", null, GraphDesc.LINE.toString(), "green", null, null, null, null, null, null, null);
gd.add("shade", null, GraphDesc.LINE.toString(), "blue", null, null, null, null, null, null, null);
gd.add("median", "sun,shade,+,2,/", GraphDesc.LINE.toString(), "magenta", null, null, null, null, null, null, null);
gd.add("diff", "sun,shade,-,ABS,-1,*", GraphDesc.AREA.toString(), "yellow", null, null, null, null, null, null, null);
gd.setGraphTitle("Temperatures in May 2003");
gd.setVerticalLabel("temperature");
return gd;
}