geom_hex and fill

[Claudia Beleites]

Dear all,

I want to produce a plot of hexagons, filled with a colour that I calculate
externally.
I easily obtain a data.frame with the centres of the hexagons and the desired
colours.

Everything goes fine until I try filling with a discrete variable. (Obviously at
the end there's to be a scale_fill_identity, but that doesn't change anything).
Playing around with aes (colour = col) seems to have the same effect.

What am I missing?

Best regards,

Claudia

library (ggplot2)
library (hexbin)

df <- data.frame (x = 1 : 3,
y = (1:3)*sqrt (3),
col = c ("#008000", "#0000A0", "#A00000"))

ggplot (data = df, aes (x = x, y = y)) + geom_hex (colour = "red", stat =
StatIdentity) +
scale_x_continuous (expand = 0 : 1) + scale_y_continuous (expand = c (0, 2))
+ coord_equal ()
## fine

ggplot (data = df, aes (x = x, y = y, fill = x)) + geom_hex (colour = "red",
stat = StatIdentity) +
scale_x_continuous (expand = 0 : 1) + scale_y_continuous (expand = c (0, 2))
+ coord_equal ()
## fine

ggplot (data = df, aes (x = x, y = y, fill = col)) + geom_hex (colour = "red",
stat = StatIdentity) +
scale_x_continuous (expand = 0 : 1) + scale_y_continuous (expand = c (0, 2))
+ coord_equal ()
## size badly screwed up: far too large

--
Claudia Beleites
Dipartimento dei Materiali e delle Risorse Naturali
Università degli Studi di Trieste
Via Alfonso Valerio 6/a
I-34127 Trieste

phone: +39 0 40 5 58-37 68
email: cbel...@units.it

[Hadley Wickham]

Hi Claudia,

Try this:

ggplot (data = df, aes (x = x, y = y, fill = col, group = 1)) +

geom_hex (colour = "red", stat = StatIdentity) +
scale_x_continuous (expand = 0 : 1) +
scale_y_continuous (expand = c (0, 2)) +
coord_equal ()

The problem is that the hexagons get broken up automatically by a
discrete fill colour, and the automatic estimation of their size goes
wrong.

Hadley

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[Claudia Beleites]

Dear Hadley,

many thanks, that works beautifully.

I promise an example for the Wiki :-)

Claudia

--
Claudia Beleites
Dipartimento dei Materiali e delle Risorse Naturali

Universit� degli Studi di Trieste