map(value, istart, istop, ostart, ostop)
Re-maps a number from one range to another.
Numbers outside the range are not clamped to 0 and 1, because out-of-range values are often intentional and useful.
Type: function
Parameter(s):
- value {Number}:The value to be mapped. 
- istart {Number}:The start of the input range. 
- istop {Number}:The end of the input range. 
- ostart {Number}:The start of the output range. 
- ostop {Number}:The end of the output range. 
Returns:
- 
    {Number}:
 The mapped value.