geom_timeline_label: Add annotations to earthquakes timeline Geom

In avidclam/msdr5: Visualization of NOAA's Significant Earthquake Database

Description

This geom adds annotations of a vertical line and a location text of the earthquake to the top powerful earthquakes. Aesthetics are x, which is the date of the earthquake and label which takes the column name from which annotations will be obtained.

Usage

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

Arguments

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	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. It can also be a named logical vector to finely select the aesthetics to display.
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().
n_max	Maximum number of annotations for each level of 'y' (starting from the most powerful earthquake down)
...	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.
mag	Magnitude of the earthquake, used to find top n_max entries

Details

The bubblechart is a scatterplot with a third variable mapped to the size of points. There are no special names for scatterplots where another variable is mapped to point shape or colour, however.

Overplotting

The biggest potential problem with a scatterplot is overplotting: whenever you have more than a few points, points may be plotted on top of one another. This can severely distort the visual appearance of the plot. There is no one solution to this problem, but there are some techniques that can help. You can add additional information with geom_smooth(), geom_quantile() or geom_density_2d(). If you have few unique x values, geom_boxplot() may also be useful.

Alternatively, you can summarise the number of points at each location and display that in some way, using geom_count(), geom_hex(), or geom_density2d().

Another technique is to make the points transparent (e.g. geom_point(alpha = 0.05)) or very small (e.g. geom_point(shape = ".")).

Aesthetics

geom_point understands the following aesthetics (required aesthetics are in bold):

• x

• y

• alpha

• colour

• fill

• group

• shape

• size

• stroke

Learn more about setting these aesthetics in vignette("ggplot2-specs")

Examples

## Not run: 
earthquakes %>%
  eq_clean_data() %>%
  eq_location_clean() %>%
  filter(YEAR >= 2000) %>%
  filter(COUNTRY %in% c("USA", "MEXICO")) %>%
  ggplot(aes(x = DATE, y = COUNTRY, color = DEATHS, size = EQ_PRIMARY)) +
  geom_timeline_label(aes(mag = EQ_PRIMARY, label = LOCATION_NAME), n_max = 5) +
  geom_timeline() +
  scale_size_continuous(name = 'Richter scale value', guide = guide_legend(order = 1)) +
  scale_color_continuous(name = '# of Deaths', guide = guide_colorbar(order = 2)) +
  theme_eq_custom()

## End(Not run)

avidclam/msdr5 documentation built on May 29, 2019, 11:02 p.m.