outlier {dave} | R Documentation |

Identifies outliers based on the nearest neighbour criterion. It starts by computing a matrix of distances (correlation, r, used as distance, dr=(1-r)/2). Variables with nearest neighbour distance larger than parameter thresh are considered outliers.

```
outlier(veg, thresh, y,...)
outly(veg, thresh = 0.2, y = 0.5)
## Default S3 method:
outlier(veg, thresh, y,...)
## S3 method for class 'outlier'
plot(x,...)
## S3 method for class 'outlier'
print(x,...)
```

`veg` |
This is a vegetation data frame, releves are rows, species columns |

`thresh` |
Threshold nearest neighbour distance for outliers |

`y` |
Transformation of species scores: x'= x exp(y) |

`x` |
An object of class "outlier" |

`...` |
Parameter out.seq, the plotting interval |

An object of class "oulier" with at least the following items:

`threshold` |
Threshold nearest neighbour distance for considering outliers |

`y` |
Transformation of species scores: x'= x exp(y) |

`rel.names` |
All row names |

`neigh.names` |
Names of the corresponding nearest neighbours |

`neigh.dist` |
Distance to the nearest neighbour |

`olddim` |
Dimensions of data frame veg |

`newdim` |
Dimensions of data frame with outliers erased |

`new.data` |
Vegetation data frame without outliers |

`pco.points` |
The pco ordination scores use for plotting |

Otto Wildi

Wildi, O. 2017. Data Analysis in Vegetation Ecology. 3rd ed. CABI, Oxfordshire, Boston.

```
o.outlier<- outlier(nveg,thresh=0.2,y=0.5)
o.outlier # a list of all variables
plot(o.outlier) # nearest neighbour histogram and
# pco ordination
```

[Package *dave* version 2.0 Index]