# Data Scales¶

Scales (or “transformations”) are commonly used to improve visualization of cytometry data. Scales are only used for gating and for displaying dot plots and histograms; statistics are calculated on raw, compensated data.

## Minimum and maximum values¶

All scales have minimum and maximum values. Data points outside of this range are shown as a pile-up on the axes. Gates that include the minimum or maximum scale value will include all datapoints below or above the minimum or maximum, respectively.

## Scale Types¶

### Linear¶

Linear scales do not affect the data, except that data is clamped within the minimum and maximum values as described above.

### Log¶

Log scales apply the common logarithm function (log10). Because \(\log(x)\) approaches negative infinity as \(x\) approaches zero, all log scales have a minimum value of 1.0.

### ArcSinh (inverse hyperbolic sine)¶

A limitation of the log scale is the inability to show values at or below zero. The arcsinh function is log-like, but is able to show zero and negative values.

The **cofactor** parameter adjusts “compression” around zero by dividing the input
by this value.

The explicit formula is \(ArcSinh(\frac{x}{c})\). This scale type is generally interchangeable with “biexponential” or “logicle” scales.

Biexponential Scales

Biexponential scales are not yet supported. ArcSinh is a close approximation to biexponential scales.

## Changing scales after gating¶

If you change a scale type or arcsinh cofactor after gating, CellEngine will re-fit the gate coordinates to the new scale. However, because log and arcsinh are non-linear functions, gate edges that were straight with one scale may be curved with another scale. CellEngine does not use curved gate edges; thus, the adjusted gate is only approximately positioned. Depending on the magnitude of the scale change, your gates may require adjustments after changing a scale.

## Importing scales from other experiments¶

You can import scales from another experiment from the gating page.