colourScale.fsx

// 12 step cold-hot colour scale from http://geog.uoregon.edu/datagraphics/color_scales.htm
let rowColourClass (x:double) (min:double) (max:double) =
    let idx =
        match x with
        | x when x > max -> 0
        | x when x < min -> 12
        | _ -> (int)(Math.Round((x - min)/((max - min)/12.)))
    [|"#002aff"; "#1965ff"; "#3299ff"; "#65ccff"; "#99edff"; "#ccffff"; "#ffffcc"; "#ffee99"; "#ffcc65"; "#ff9932"; "#ff6619"; "#ff2a00"|]
    |> Array.rev
    |> fun a -> a.[idx]