geom_timeline_label: Add Labels to Timeline
In maianhdang/noaa.visualise: NOAA Earthquakes Processing and Visualising

Description Usage Arguments Note Examples

geom_timeline_label() is used together with geom_timeline for adding the annotations to the timeline. The subset is taken the n_max number of earthquakes. Aesthetics are x, as the date of earthquakes and label would be taken from the column name.

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geom_timeline_label(mapping = NULL, data = NULL, n_max = NULL,
  stat = "timeline", position = "identity", na.rm = FALSE,
  show.legend = NA, inherit.aes = TRUE, ...)

`mapping`	Set of aesthetic mappings created by `aes` or `aes_`. If specified and `inherit.aes = TRUE` (the default), it is combined with the default mapping at the top level of the plot. You must supply `mapping` if there is no plot mapping.
`data`	The data to be displayed in this layer. There are three options: If `NULL`, the default, the data is inherited from the plot data as specified in the call to `ggplot`. A `data.frame`, or other object, will override the plot data. All objects will be fortified to produce a data frame. See `fortify` for which variables will be created. A `function` will be called with a single argument, the plot data. The return value must be a `data.frame.`, and will be used as the layer data.
`n_max`	A integer which indicates the number of the largest earthquakes to have the label
`stat`	The default set is `"timeline"`
`position`	Position adjustment, either as a string, or the result of a call to a position adjustment function.
`na.rm`	If `FALSE`, the default, missing values are removed with a warning. If `TRUE`, missing values are silently removed.
`show.legend`	logical. Should this layer be included in the legends? `NA`, the default, includes if any aesthetics are mapped. `FALSE` never includes, and `TRUE` always includes.
`inherit.aes`	If `FALSE`, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. `borders`.
`...`	other arguments passed on to `layer`. These are often aesthetics, used to set an aesthetic to a fixed value, like `color = "red"` or `size = 3`. They may also be parameters to the paired geom/stat.

The aes xmin and xmax as the starting and ending points of the timeline, which should be clarified.

The aes x is the date of the earthquakes

The optiona aes y is the a factor indicating some stratification in which case multiple time lines will be plotted for each level of the factor (e.g. COUNTRY)

The aes label is the column in the data frame to obtain the text annotation

## Not run: 
ggplot(input_data, aes (x = date, y = COUNTRY,
color = as.numeric(DEATHS), size = as.numeric(EQ_PRIMARY))) +
geom_timeline(aes(xmin = as.Date("1900-01-01"), xmax =  as.Date("1925-01-01")) +
geom_timeline_label(aes(label = LOCATION_NAME,
xmin = as.Date("1900-01-01"), xmax = as.Date("1925-01-01")),
n_max = 5) +
theme_timeline()
## End(Not run)