How to define two indicator values walk together, just like footprint

Here is Bruce Oil Daycharts

Red line is EMA 7
Purple line is BB 17,1

Trend is friend, but hard to define.

From 03/08 to 03/16, red line walk together with purple line => Shape Downtrend
From 03/17 to 03/27, red line Not walk together with purple. No trade as not sure
Jan to Feb, near no walk together, subway
From 03/31 to 04/12, red line walk together with purple line => Shape Uptrend

Human can easy find out on visual inspection
How to defind absvalue(EMA7 - BB17 UPPER) is small enough as if walk together

Sometime is forex and using very small value whereas HSI or DOW give 2x thousand on price

For valuation
Above BB upper band and EMA 7 walk together Good uptrend
Below BB lower band and EMA 7 walk together Good downtrend
Within BB band, subway need stand up and wait breakout