# flag_bad

##

Last updated Sun Sep 19 14:20:32 1999

Flag data as bad in a vector

## 1. SYNOPSIS

[v, mask] = flag_bad(v, sig_max )

## 2. DESCRIPTION

Calculate the mean value of the non-NaN in a vector, standard deviation and residuals for each element. An element is considered as bad if the absolute value of its residual is larger than a certain threshold value. The latter is determined as a factor times the standard deviation.

This function can be used to detect vector elements that are much more different than the other ones.

## 3. PARAMETERS

v

  Data vector.

sig_max

  Factor used to calculate the threshold value. A typical value is 2.5.

## 4. RETURNS

v

  Vector with bad elements replaced by NaN.

mask

  Vector of ones or zeros,zeros specifying elements in v that have been flagged as bad,or that were already set to NaN on input.

## 5. AUTHORS

Pierre Jaccard, Geophysical Institute, University of Bergen, 1999