Thin out closely-timed bursts of locations

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`lxy` |
A LoCoH-xy object |

`id` |
The id value(s) to be thinned |

`thresh` |
The threshhold for delta.t below which a pair of points is considered to be part of a burst, expressed either as a proportion of the median sampling frequency (0..1) or an absolute unit of time (in seconds) |

`replace` |
The burst replacement method ('mean' or 'median') |

`info.only` |
Show information about number of bursts (only) |

`dt.int.round.to` |
The proportion of the median sampling frequency that time intervals will be rounded to when computing the frequency table of sampling intervals (no change is made to the time stamps) |

`tau.diff.max` |
The maximum deviation from tau (the median delta.t of the entire dataset), expressed as a proportion of tau, that time difference between two points must fall for the distance between those two points to be included in the calculation of the median step length |

`status` |
Show status messages. T/F |

a LoCoH-xy object

Many GPS devices have a feature to save 'bursts' of points close together in time (relative to the dominant sampling frequency) The 'burst' feature should not be confused with point averaging, whereby a GPS device internally averages locations for a period of time (e.g., 2 minutes) but saves a single location.

This function can be used to thin out 'bursts' of locations, when they are an artifact of data collection and therefore not desirable. Each group of points in a burst is replaced with a single point.

`thresh`

is a numeric value for identifying which points should be considered part of
a burst. When `thresh`

< 1, it is taken to be a proportion of the median sampling frequency (0..1), and any
pair of points that are recorded closer in time are considered part of a 'burst', When `thresh`

> 1,
it is taken to be absolute unit of time (in seconds).

To identify whether there are bursts in a LoCoH-xy dataset, and the sampling frequency of those bursts (i.e., the value

The two replacement methods are /codereplace="mean", in which case a burst of locations is replaced by a single point consisting of the
spatial and temporal average of the burst, or /codereplace="median" in which case a burst of locations is replaced by the location
at the temporal median of the burst. If /codereplace="mean", then any ancillary variables for the 'new' points will be set to `NA`

.

Because this function deletes points, the nearest neighbor lookup table of the LoCoH-xy object (if any) will be deleted, and the parameters for random walk model will be recomputed.

`lxy.plot.freq`

, `lxy.thin.byfreq`

Questions? Problems? Suggestions? Tweet to @rdrrHQ or email at ian@mutexlabs.com.

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