Using text for x-axis

Dear All
 
I am trying to make a simple XY plot with math type  x ---> y ,
MathType Set(x, y)
but the domain for x is "text" and y is double .
X= "text1"  "text2"  "text3" etc
Y= 2.4  4.5 , 6.9 etc
 
my question is can a Gridded2DSet be used , I am not sure how the text part will
be handled by the constructor. I tried making a fieldImpl for the text but it 
throws 
exceptions.
 
I welcome any Ideas on this.
 
thanks
 
Isaac