Let’s say you have a number scale that has a minimum and a maximum. You have a second number scale with a min and a max. How do you map an arbitrary value somewhere on that number scale to the second scale?
Let’s call the top scale a with a0 = 10 and a1 = 40. The bottom scale goes from b0 = -1 to b1 = 1. We want to map the value a = 20 to some value of b. The equation is:
If you are normalising a value to between 0 and 1, then b0 = 0 and b1 = 1. The equation reduces nicely to:
C# code example
public double MapValue(double a0, double a1, double b0, double b1, double a)
return b0 + (b1 - b0) * ((a-a0)/(a1-a0));