# Statistical Analysis From Phase to Displacement result

Hi guys! i’ve tried to perform statistical analysis from ROI geometry at merapi volcano. the results shown like the pic above. what does the Max Error, ENL and Coef varianmeans? how it is being calculated?

Thanks

the coefficient of variation is the standard deviation of all values divided by the average (mean) value.

Thanks for the answer. how about the Max Error means? how is it being estimated?

I’m sorry mr. Braun, i still have no clue about Max Error means. could you please answer my question? thanks

I just don’t know it, sorry. Maybe someone else can comment.

I think I can shed some light on these values:
Coef Variation:
This is differently computed depending on the unit of the data:

``````if (unit != null && unit.contains("intensity")) {
final double m = valueSum / sampleCount;
final double m2 = sqrSum / sampleCount;
cv = Math.sqrt(m2 - m*m) / m;
} else {
final double m4 = power4Sum / sampleCount;
final double m2 = sqrSum / sampleCount;
cv = Math.sqrt(m4 - m2*m2) / m2;
}
``````

The code can be found here: snap-engine/SummaryStxOp.java
Background information: Coefficient of variation - Wikipedia

ENL:

``````if (unit != null && unit.contains("intensity")) {
final double m = valueSum / sampleCount;
final double m2 = sqrSum / sampleCount;
final double mm = m*m;
enl = mm / (m2 - mm);
} else {
final double m4 = power4Sum / sampleCount;
final double m2 = sqrSum / sampleCount;
final double m2m2 = m2*m2;
enl = m2m2 / (m4 - m2m2);
}
``````

The code can be found here: snap-engine/SummaryStxOp.java
Background information: Estimation of the Equivalent Number of Looks in Polarimetric Synthetic Aperture Radar Imagery | IEEE Journals & Magazine | IEEE Xplore

Max error:
This is actually the bin size.
The code can be found here: snap-desktop/StatisticsPanel.java

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