Define new symbol characteristics. SYMBOL statements are assigned to the values of CITY in alphabetical order. For example, the value Minn is assigned SYMBOL1.

symbol1 interpol=spline width=2 value=triangle c=steelblue
        ;
symbol2 interpol=spline width=2 value=circle c=indigo
        ;
symbol3 interpol=spline width=2 value=square c=orchid
        ;