R: Shape palette from Cleveland "Elements of Graphing Data"...

cleveland_shape_pal {ggthemes} | R Documentation

## Shape palette from Cleveland "Elements of Graphing Data" (discrete).

### Description

Shape palettes for overlapping and non-overlapping points.

### Usage

    cleveland_shape_pal(overlap = TRUE)

### Arguments

`overlap` | `logical` Use the scale for overlapping points?

### Note

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 palatte 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.

### References

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, http://www.jstor.org/stable/1390760

### See Also

Other shapes: `circlefill_shape_pal`, `scale_shape_circlefill`, `scale_shape_cleveland`, `scale_shape_tremmel`, `tremmel_shape_pal`

### Examples

    ###   (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)

[Package ggthemes version 3.4.2 Index]