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Flame geom for MHW visualisation

Source: R/geom_flame3.R
geom_flame3.Rd

A ggplot2 geom that fills the area between two lines (temperature and threshold) where the first exceeds the second, creating "flame" polygons. For cold-spells, set reverse = TRUE to fill where y < y2.

Usage

geom_flame3(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  n = 0,
  n_gap = 0,
  reverse = FALSE,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings. Requires x, y, and y2. An optional depth aesthetic can be mapped for depth-resolved data (see Details).

data

The data to display.

stat

The statistical transformation. Default "identity".

position

Position adjustment. Default "identity".

...

Additional arguments passed to the layer.

n

Minimum number of consecutive exceeding points. Default 0.

n_gap

Maximum gap to bridge between exceeding segments. Default 0.

reverse

Logical. If TRUE, fill where y < y2 (for cold-spells). Default FALSE (fill where y > y2).

na.rm

Remove NAs? Default FALSE.

show.legend

Show legend? Default NA.

inherit.aes

Inherit aesthetics from the plot? Default TRUE.

Value

A ggplot2 layer.

Details

geom_flame3() finds exceedance runs by walking each group's rows in order, so a single group must be one continuous series through x. For depth-resolved data (e.g. hw3_export() on a ts2clm3(depth_range = ...) product), map depth as an aesthetic – aes(x = t, y = temp, y2 = thresh, depth = depth) – and it is automatically folded into the row grouping, so each depth level gets its own exceedance runs instead of being treated as one series with depths interleaved. This happens even though depth is a plain numeric column, which ggplot2's own default grouping would otherwise merge into a single group (unlike a discrete aesthetic such as colour).

Examples

library(ggplot2)
# Simple example with synthetic data
df <- data.frame(
  x = 1:100,
  y = sin(seq(0, 4 * pi, length.out = 100)) + 2,
  y2 = 1.5
)
ggplot(df, aes(x = x, y = y, y2 = y2)) +
  geom_flame3() +
  geom_line()