I am using qplot from ggplot2 to plot the distances of seeds dispersed by different species in R. When I use geom='density', it works just fine! But what I really want is a frequency/area plot, for which I get an error I do not know how to address.
This works:
qplot(Dist,data=testx,geom="density",fill=Animal,log=c('x','y'),alpha=I(0.5))
This doesn't work:
qplot(Dist,data=testx,geom="area",fill=Animal,log=c('x','y'))
Error in exists(name, envir = env, mode = mode) :
argument "env" is missing, with no default
Help? Thanks!
The reason for that error (the message is quite obscure, I agree) is that you are trying to use geom_area (qplot(geom = "area") is roughly the same as + geom_area()). Whereas geom_density only requires x (x = Dist in your case), this is not enough for geom_area, as it additionally uses ymax (for help pages, see this, which links to this).
Here's an example of density and frequency plots which you may adjust for your data:
ggplot(data=diamonds, aes(x=carat, fill=clarity)) + geom_density(alpha=0.5)
ggplot(data=diamonds, aes(x=carat, colour=clarity)) + geom_freqpoly()
Your code sample is not reproducible, so I cannot verify the following line, but
ggplot(data=testx, aes(x=Dist, colour=Animal)) + geom_freqpoly() +
scale_x_log10() + scale_y_log10()
may be what you need.
Regarding this error message it might help to point out that this is the error message you get when you use an empty data set for a histogram:
df <- data.frame(testx = rnorm(0))
p <- ggplot(df, aes(x=testx)) +
geom_histogram()
plot(p)
Error in exists(name, envir = env, mode = mode) :
argument "env" is missing, with no default
Unfortunately, the error message is not very helpful at all in this case. When I first ran into this problem it took me some time to figure out that I just accidentally had ended up with an empty data frame. The OP probably had a different problem, but it is always good to know that this error is connected to this stupid mistake.
