geom_timeline: A 'ggplot2' layer function for timelines
In RussellPolitzky/quake: Earthquake Data Visualizations

Description Usage Arguments Value See Also Examples

View source: R/geom_timeline.R

geom_timeline is a ggplot2 layer function representing timelines. geom_timeline plots a time line of events ranging in time from xmin to xmax dates, with a point for each event. Optional aesthetics include color, size, and alpha (for transparency). The x aesthetic is usually a Date and an optional y aesthetic is a factor indicating stratification, in which case multiple time lines will be plotted for each factor level (e.g. factors may be countries so that quakes are grouped by country in the timeline plot).

geom_timeline(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", na.rm = FALSE, show.legend = NA,
  inherit.aes = TRUE, xmin = .Machine$double.xmin,
  xmax = .Machine$double.xmax, ...)

`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.
`stat`	The statistical transformation to use on the data for this layer, as a string.
`position`	Position adjustment, either as a string, or the result of a call to a position adjustment function.
`na.rm`	a `boolean` indicating whether or not to remove NAs. `na.rm = FALSE` by default.
`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`.
`xmin`	any type coercible to a `numeric` without additional parameters. `xmin` is usually a `Date` and should correspond to the given `x` aesthetic, since it specifies the lower bound that aesthetic. That's so say, the timeline will only show events in the data where `x >= xmin`.
`xmax`	any type coercible to a `numeric` without additional parameters. `xmin` is usually a `Date` and should correspond to the given `x` aesthetic, since it's specifies the upper bound for that aesthetic. That's so say, the timeline will only show events in the data where `x <= xmin`.
`...`	a `...` indicates a list of additional parameters used for a geom. `geom_timeline` doesn't make use of these.

a ggplot2 layer object.

linkgeom_timeline_label

library(quake     )
library(magrittr  )
library(data.table)
library(ggplot2   )

# Create dummy data

n         <- 100 # start with 100 data samples
countries <- c("USA", "China", "India", "South Africa")

dt <- data.table(
  date      = as.Date('2017-01-01') + seq(1, 365, 365/n),
  country   = factor(sample(countries, replace = TRUE, size = n)),
  intensity = runif(n)*10, # mag is somewhere beteen 0 and 10
  deaths    = runif(n)*12
)

head(dt) # show dummy data

start_date       <- as.Date('2017-07-01') # only show quakes from July 2017
end_date         <- as.Date('2017-07-30') # only show quakes from July 2017
no_labels_toshow <- 3 # show only three labels from highest intensity quakes

dt %>%
  ggplot() +
  geom_timeline_label(
    aes(
      label = as.character(country),
      x     = date     ,
      y     = country  ,
      size  = intensity
    ),
    n_max = no_labels_toshow,
    xmin  = start_date,
    xmax  = end_date
  ) +
  geom_timeline(
    aes(
      x    = date     ,
      y    = country  ,
      size = intensity,
      col  = deaths
    ),
    xmin  = start_date,
    xmax  = end_date,
    alpha = 0.8
  ) +
  labs(x = "DATE")                                     +
  scale_size_continuous (name = "Richter scale value") +
  scale_color_continuous(name = "# deaths"           ) +
  theme_classic()                                      +
  theme_timeline_with_y_axis_text