I am trying to construct a het map type of plot with rectangular bins colored to indicate the number of records for a given value within different categories. I am getting close to what I want with ggplot2 and stat_bin2d. However if you run the code you will se below that the placement of the bins on the graph is incorrect. Categories A and C should have equal overlap with category B but they don't. Any idea what I am doing wrong / better approaches for this? library(ggplot2) mt <- as.data.frame(matrix(rep(c("A", "B", "C"), each = 10), 30, 2)) mt[, 2] <- c(rep(18, 5), rep(20, 5), rep(20, 10), rep(20, 5), rep(22,5)) colnames(mt) <- c("group", "count") ggplot(data=mt,aes(x=mt$count, y=mt$group)) + stat_bin2d(binwidth = c(.5, .5)) cheers Heath [[alternative HTML version deleted]]