Re-maps a number from one range to another. In the example above, the number '25' is converted from a value in the range 0..100 into a value that ranges from the left edge (0) to the right edge (width) of the screen. Numbers outside the range are not cla

map.js

var map = function(value, istart, istop, ostart, ostop) {
    return ostart + (ostop - ostart) * ((value - istart) / (istop - istart))
};