I am using ggplot and posted this question at that helplist. It was suggested that I try a more general R-help list for a possible solution to this problem.
Within ggplot, I am using geom_area with red and blue and expect where they overlap should be purple. But instead, it's dark red. Playing with alpha and with different colors doesn't seem to solve the problem. Here's a very simple reproducible example R --arch x86_64 library(ggplot2) x<-c(24,55,69,73) y<-c(44,56,12,90) z<-c(1,2,3,4) a<-data.frame(pos=z, y=y, x=x) ex<- ggplot(data=a, aes(pos)) + geom_area(aes(y = y),fill="navyblue", alpha = 0.7, position="identity") + geom_area(aes(y = x), fill= "darkred", alpha = 0.7,position="identity" ) + opts(panel.background = theme_rect(fill = "white")) ex Likewise, with blue and yellow, I would expect overlap to be green. Are there any solutions to this that would allow color overlaps to lead to the "expected" color? Thank you. > sessionInfo() R version 2.10.0 (2009-10-26) x86_64-apple-darwin9.8.0 locale: [1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8 attached base packages: [1] grid stats graphics grDevices utils datasets methods [8] base other attached packages: [1] ggplot2_0.8.3 reshape_0.8.3 plyr_0.1.9 proto_0.3-8 [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.