Displaying the number of counts per bin in a ggplot2 hexbin graph - r

Question

I'm working on a project to simulate the movement of missing ships. I've made a distribution map using this code:
library("ggplot2")
a <- rnorm(1000, 30.2, 2)
b <- rnorm(1000, 10, 5)
y <- (x + a + b) * 0.6
df <- data.frame(x,y)
p <- ggplot(df,aes(x=x,y=y)) +
ggtitle("A Priori Map") + xlab("Longtitude") + ylab("Latitude") +
scale_fill_gradientn(colors = topo.colors(10))
p + stat_binhex(show.legend = T, bins = 20)
This produces a map like this:
A hexbin map
However, instead of showing the number of counts using a color, I would like to show the actual count in a point. So if the program 'landed' on a certain point 3 times, it would display '3'.
How can this be done in R?

Answer 1

Here's how to add counts to the existing graph:
library(ggplot2)
theme_set(theme_bw())
set.seed(2)
a <- rnorm(1000, 30.2, 2)
b <- rnorm(1000, 10, 5)
x = rnorm(1000)
y <- (x + a + b) * 0.6
df <- data.frame(x,y)
p <- ggplot(df,aes(x=x,y=y)) +
ggtitle("A Priori Map") +
xlab("Longtitude") + ylab("Latitude") +
scale_fill_gradientn(colors = topo.colors(10)) +
stat_binhex(show.legend = T, bins = 20)
p + geom_text(stat="binhex", bins=20, aes(label=..count..), show.legend=FALSE,
colour=hcl(15,100,60), fontface="bold", size=3.5)
To remove the fill colours, you could do:
ggplot(df,aes(x=x,y=y)) +
ggtitle("A Priori Map") +
xlab("Longtitude") + ylab("Latitude") +
stat_binhex(bins = 20, fill=NA, colour="black") +
geom_text(stat="binhex", bins=20, aes(label=..count..), colour="red")
You could also use text size to highlight the regions of highest density:
ggplot(df,aes(x=x,y=y)) +
ggtitle("A Priori Map") +
xlab("Longtitude") + ylab("Latitude") +
stat_binhex(show.legend = T, bins = 20, fill=NA, colour="grey70") +
geom_text(stat="binhex", bins=20, aes(label=..count.., size=..count..), colour="red") +
scale_size_continuous(range=c(3,6)) +
guides(size=FALSE)
Which also works without the hex-grid:
ggplot(df,aes(x=x,y=y)) +
ggtitle("A Priori Map") +
xlab("Longtitude") + ylab("Latitude") +
geom_text(stat="binhex", bins=20, aes(label=..count.., size=..count..), colour="red") +
scale_size_continuous(range=c(3,6)) +
guides(size=FALSE)