These functions facilitate the coloring of tracks by annotating tracking data with time/location specific information and computing color arguments for `plot`

.

annotate(object,by="all",cores=1,...)
color(object,by="time",col.fn=NULL,alpha=1,dt=NULL,cores=1,...)

## Arguments

object |
A `telemetry` object or list of objects. `color` can also take `ctmm` and `UD` objects. |

by |
What to `annotate` or `color` times by. Options include `"individual"` , `"time"` , `"sun"` , `"moon"` , `"season"` , and `"tropic"` (see Details below). `ctmm` and `UD` objects can only be colored by `"individual"` . |

col.fn |
Optional coloring function that can take a [0,1] interval and alpha channel argument. |

alpha |
Base alpha channel value. |

dt |
Sampling interval specification for making oversampled times more transparent. If `NULL` , the median will be used. Disabled if zero. |

cores |
Number of annotations or overlap calculations to peform in parallel. `cores=0` will use all cores, while `cores<0` will reserve `abs(cores)` . |

... |
Additional arguments. |

## Details

Annotated `telemetry`

objects are required for `color`

`by`

arguments `"sun"`

, `"moon"`

, `"season"`

, or `"tropic"`

.

`by="time"`

colors tracking data with a gradient that increases in time.
`by="sun"`

colors according to the sine of the sun's altitude, which is proportional to solar flux during daylight hours.
`by="moon"`

colors according to the illuminated fraction of the moon.
`by="season"`

colors according to the length of the day, and therefore corresponds to the local season.
`by="tropic"`

currently colors according to the calender day, but will eventually be upgraded to tropical-year cycle.

`by="individual"`

assigns colors to minimize the maximum combined spatial and color overlap.
Finding the best color assignment is an \(NP\)-hard problem that is here approximated in \(O(N^3)\) time with a custom greedy algorithm.

Other named columns in the `telemetry`

object can also be used with `color`

, by specifying the column name with `by`

.

## Value

`annotate`

returns an annotated telemetry object with extra columns to facilitate coloring.
`color`

returns a valid `col`

argument for `{plot.telemetry}`

.

## Author

C. H. Fleming.

## See also

## Examples

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

#> DOP values missing. Assuming DOP=1.

# }