[R] Getting discrete colors on plot
mlhoward at avalon.net
Thu Jan 17 18:02:15 CET 2013
This is my first post; I'm new to R but am a senior statistical programmer. I have done a lot of graphs using SAS Graph but now am trying to transition to using graphs in R.
I'm trying to produce a graph where the colors have three categories- ideally I would like them to be Green for good, Yellow for Questionable, and Red for bad.
So I tried to do this in GGPLOT; here is my code:
id <- c(1,2,3,4,5)
x1 <- c(5,2,3,5,1)
x2 <- c(4,1,3,5,1)
x3 <- c(5,2,3,5,1)
x4 <- c(4,3,3,5,1)
x5 <- c(3,1,3,5,1)
colorvar <- c(3,1,2,3,1)
mydata <- data.frame(id,x1,x2,x3,x4,x5,colorvar)
# convert to long format
mydata_long <- melt(mydata, id=c("id", "colorvar"))
p <- ggplot(data=mydata_long,
group=id, colour = colorvar)) +
This works, but I get more colors on the graph than my colorvar has. I have 3 colors on my colorvar, but 5 colors show up on the graph, including 1.5 and 2.5. How do I tell ggplot only to use the 3 colors and not give me a gradient of colors? Also how would I specify the colors that I want, such as the RGB equivalents of green, yellow, and red? My real data will have many more records.
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