How to fill the plot area using geom_raster or geom_tile

ggplot2, r

Solution

Update It appears that the issue has been resolved in recent versions of ggplot2.

It's something to do with there being just one level in the `id` factor. Change the `id` factor to numeric, or change the `id` factor so it has two levels, then the tiles fill the space. Also, `coord_equal()` with the original `id` factor will give a long narrow plot, but again filling the space.

## Your data
df = read.table(text = "
id  variable   value
ID1    1A      91.98473282
ID1    2A      72.51908397
ID1    2B      62.21374046
ID1    2D      69.08396947
ID1    2F      83.39694656
ID1    2G      41.60305344
ID1    2H      63.74045802
ID1    9A      58.40839695
ID1    9C      61.10687023
ID1    9D      50.76335878
ID1    9K      58.46183206", header = TRUE, sep = "")

library(ggplot2)

 # Change the id factor
 df$id2 = 1                   # numeric
 df$id3 = c(rep("ID1", 5), rep("ID2", 6))      # more than one level

 # Using the numeric version
 ggplot(df, aes(variable, id2)) +
          geom_raster(aes(fill = value)) + 
          scale_y_continuous(breaks = 1, labels = "ID1", expand = c(0,0)) + 
          scale_x_discrete(expand = c(0,0)) +
          scale_fill_gradient(low = "white",
          high = "steelblue")

# Two levels in the ID factor
ggplot(df, aes(variable, id3)) +
          geom_tile(aes(fill = value)) + 
          scale_fill_gradient(low = "white",
          high = "steelblue") 

# Using coord_equal() with the original id variable
ggplot(df, aes(variable, id)) +
          geom_tile(aes(fill = value)) + 
          scale_fill_gradient(low = "white",
          high = "steelblue") +
          coord_equal()

Problem

I have the following data frame: ``` id variable value ID1 1A 91.98473282 ID1 2A 72.51908397 ID1 2B 62.21374046 ID1 2D 69.08396947 ID1 2F 83.39694656 ID1 2G 41.60305344 ID1 2H 63.74045802 ID1 9A 58.40839695 ID1 9C 61.10687023 ID1 9D 50.76335878 ID1 9K 58.46183206 ``` I'm using ggplot2 to generate a heat map with the data: ``` ggplot(data, aes(variable, id)) + geom_raster(aes(fill = value)) + scale_fill_gradient(low = "white", high = "steelblue") ``` The plot looks like this: http://dl.dropbox.com/u/26998371/plot.pdf I would like for the tiles to fill the plot space on the y-axis rather than leave a space above and below. I'm sure there is a simple answer. Any help would be greatly appreciated. scale_y_discrete(expand = c(0, 0)) didn't work with the y-axis, but scale_x_discrete(expand = c(0, 0)) will work on the x axis to fill the plot space.

Original source