Shape palette from Cleveland "Elements of Graphing Data" (discrete).
Shape palettes for overlapping and non-overlapping points.
cleveland_shape_pal(overlap = TRUE)
overlap |
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In the Elements of Graphing Data, W.S. Cleveland suggests two shape palettes for scatter plots: one for overlapping data and another for non-overlapping data. The symbols for overlapping data relies on pattern discrimination, while the symbols for non-overlapping data vary the amount of fill. This palette attempts to create these palettes. However, I found that these were hard to replicate. Using the R shapes and unicode fonts: the symbols can vary in size, they are dependent of the fonts used, and there does not exist a unicode symbol for a circle with a vertical line. If someone can improve this palette, please let me know.
Following Tremmel (1995), I replace the circle with a vertical line with an encircled plus sign.
The palette cleveland_shape_pal() supports up to five values.
Cleveland WS. The Elements of Graphing Data. Revised Edition. Hobart Press, Summit, NJ, 1994, pp. 154-164, 234-239.
Tremmel, Lothar, (1995) "The Visual Separability of Plotting Symbols in Scatterplots", Journal of Computational and Graphical Statistics, https://www.jstor.org/stable/1390760
Other shapes:
circlefill_shape_pal(),
scale_shape_circlefill(),
scale_shape_cleveland(),
scale_shape_tremmel(),
tremmel_shape_pal()
### (discrete).
library("ggplot2")
p <- ggplot(mtcars) +
geom_point(aes(x = wt, y = mpg, shape = factor(gear))) +
facet_wrap(~am) +
theme_bw()
# overlapping symbol palette
p + scale_shape_cleveland()
# non-overlapping symbol palette
p + scale_shape_cleveland(overlap = FALSE)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.