geom_timeline: Geom function for plotting a time line of earthquakes
In avidclam/msdr5: Visualization of NOAA's Significant Earthquake Database

Description Usage Arguments Details Overplotting Aesthetics Examples

View source: R/geom_timeline.R

This ggplot2 geom should be used for plotting earthquakes as points along the date axis (x). Optional aesthetics include color, size, and alpha (for transparency). Optional y aesthetic is a factor indicating some stratification in which case multiple time lines will be plotted for each level of the factor (e.g. country).

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geom_timeline(mapping = NULL, data = NULL, stat = "identity",
  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.
`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()`.
`...`	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 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.

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 = ".")).

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")

## 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() +
  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)