get_drinking_event: Get drinking events from movement data
In rpatin/drinking: Drinking event from movement data

get_drinking_event assumes that when animals cross a certain threshold of distance to water they go drinking. It identifies unique drinking events given a certain return time above which it is considered as a new visit. Distance to water might be provided as a SpatialPointsDataFrame or as two columns (named dist2water & waterholes) in the dataframe df.

1 2	get_drinking_event(df, water_layer = NULL, threshold = 500, returnTime = 6, projstring, id = F)

`df`	a dataframe with at least coordinates `df$x`, `df$y` and date and time in `df$dateTime` in POSIXct class.
`water_layer`	a SpatialPointsDataFrame of waterhole with column `$name` in data slot. If NULL, function assumes that column `df$dist2water` gives distance to water
`threshold`	distance below which animals are considering going to drink
`returnTime`	return time (in hours) above which an animals can be considering returning drinking to the former waterhole
`projstring`	CRS projection of data
`id`	if TRUE calculate distance for individuals identified by column `df$id`