2 indicators in one indicator window, how is their position calculated/modified so their range matches?

[meiti]

Hello!

When you put 2 indicators in same indicator window what value ranges doesn't match then metatrader is making the graph still match.

rsi and wpr has the range between 0 to (-)100 what can easily be mapped in graph however momentum has a range from 90-110.

The reason why i'm trying to figure this out is because i wound interesting relationship between momentum and wpr but not in numbers, only in graph and I wanna make an ea out of it.
Any ideas of how the graph positions is calculated?

Thanks! 

[Stuart Browne]

If you have two sets of data with different scales, you need to "normalize" or "standardize"  either one or both sets to display on the same scale. In your example, I would keep the RSI scale of 0 to 100 and normalize the other data set (90 to 110) to scale to 0 to 100. 

There are thousands of websites you can google to understand it better but in your example you would want a formula such as:

 ScaledValue = (RSImax - RSImin)/(MomentumMax - MomentumMin)*(MomentumValue - MomentumMax) + RSImax

So in using your example again, RSImax=100, RSImin=0, MomentumMax=110, MomentumMin=90. Now lets say you have a momentum value of 105 that you want to normalize to the RSI scale of 0-100:

 

 ScaledMomentumValue = (100 - 0)/(110 - 90)*(105 - 110) + 100
                     = (100)/(20)*(-5)+100
                     = 75

Just a warning, it is possible to end up with a divide by zero error in MQL so you will need to build that check into your formula on the right side of the equation

[meiti]

Thank  you!

One side of it is explain, now only one question remains.
How exaclty do I get the min/max value for Momentum if it is calculated the followings:

 

MOMENTUM = CLOSE(i)/CLOSE(i-N)*100

source:https://www.metatrader5.com/en/terminal/help/indicators/oscillators/momentum

[Stuart Browne]

meiti:

Thank  you!

One side of it is explain, now only one question remains.
How exaclty do I get the min/max value for Momentum if it is calculated the followings:

 

source:https://www.metatrader5.com/en/terminal/help/indicators/oscillators/momentum

Welcome!

If you have a data series that doesn't have a fixed min/max (like 0 to 100) then what you need to do is record the min/max over a certain period of bars. So for instance, the momentum indicator has a "Periods" parameter (the "N" in your formula above). So all you need to do is look for the min/max values over that period. Then recalculate N periods on the close of every candle to get the new min/max of that period.

Technically, when using that approach you then have a "sample" rather than a "population" so the scaling formula should be slightly different but to be honest, this approach should work just fine for what you are doing