Extract contour lines from geom_density2d

[Serge-Étienne Parent]

Hello,

Is it possible to extract the lines, or polygons, or the points used to construct them, from a geom_density2d object?

Example:
library(ggplot2)
library(MASS)
data(geyser, "MASS")
m <- ggplot(geyser, aes(x = duration, y = waiting)) +
  geom_density2d()

In the example case, I would extract from the m object the points used to draw the isocontour lines, transform these points to another scale, then replot them using geom_polygon in the new scale. Drawing contours directly from data transformed in the new scale wouldn't be relevant.

Thanks!

Serge-Éti. Parent
Université Laval
Québec (Canada)

[Ista Zahn]

m.dat <- ggplot_build(m)[["data"]][[1]]

Best,
Ista

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