geom_flame: Create 'Flame' Ploygons.
In RmarineHeatWaves: Detect Marine Heat Waves and Marine Cold Spells

Description Usage Arguments Aesthetics Author(s) References See Also Examples

This function will create polygons between two lines. If given a temperature and theshold time series, like that produced by detect, the output will meet the specifications of Hobday et al. (2016) shown as 'flame polygons.' If one wishes to plot polygons below a given threshold, and not above, switch the values being fed to the y and y2 aesthetics. This function differs in use from event_line in that it must be created as a ggplot 'geom' object. The benefit of this being that one may add additional information to the figure as geom layers to ggplot2 graphs as may be necessary.

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geom_flame(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.
`...`	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.
`na.rm`	If `FALSE` (the default), removes missing values with a warning. If `TRUE` silently removes missing values.
`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()`.

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

x
y
y2
colour
fill
size
alpha
linetype

Robert W. Schlegel

Hobday, A.J. et al. (2016), A hierarchical approach to defining marine heatwaves, Progress in Oceanography, 141, pp. 227-238, doi: 10.1016/j.pocean.2015.12.014

event_line for a non-ggplot2 based flame function.

ts_dat <- make_whole(sst_WA)
res <- detect(ts_dat, climatology_start = "1983-01-01",
              climatology_end = "2012-12-31")
mhw <- res$clim
mhw <- mhw[10580:10690,]

## Not run: 
require(ggplot2)
ggplot(mhw, aes(x = t, y = temp)) +
  geom_flame(aes(y2 = thresh_clim_year)) +
  geom_text(aes(x = as.Date("2011-02-01"), y = 28,
  label = "That's not a heatwave.\nThis, is a heatwave.")) +
  xlab("Date") + ylab(expression(paste("Temperature [", degree, "C]")))

## End(Not run)