如何使用两个不同的数据帧使用直接标记绘制轮廓

Question

I am new to ggplot2 and having trouble adding labels with direct labels on a contour plot. I want to draw a plot with geom_point and stat_contour. The point plot and contour plot have different data respectively. I want add labels on the contour with directlabels.

Using following script, I get a plot without directlabels appropriately, but directlabel returns following error. error: stat_contour requires the following missing aethtics: x, y, z

library(ggplot2)
library(directlabels)
library(akima)

dat<- NULL
dat$x<- c(-1.0, 0.0, 1.0)
dat$y<- c(-0.5, 0.0, 0.5)
dat$z<- matrix(c(0.2,0.2,0.2,0.2,0.3,0.4,0.3,0.4,0.4),ncol=3)

dat0<-cbind( expand.grid(dat$x,dat$y),c(dat$z)) 
colnames(dat0) <- c("x", "y", "z")
dat0<-data.frame(dat0)

nDivX <- 6
nDivY <- 6
z.cubic <- with(dat, bicubic.grid(x=x,y=y,z=z, xlim=c(min(x),max(x)),ylim=c(min(y),max(y)),dx=(max(x)-min(x))/nDivX,dy=(max(y)-min(y))/nDivY) )
z.cubic<-cbind( expand.grid(z.cubic$x,z.cubic$y),c(z.cubic$z)) 
colnames(z.cubic) <- c("x", "y", "z")
z.cubic<-data.frame(z.cubic)

p0 <- ggplot(NULL)
p1 <- geom_point(data=dat0, aes(x=x,y=y) )
p <- p0 +p1 + stat_contour(data=z.cubic, aes(x=x, y=y, z=z , colour=..level..))

#without directlabels
dev.new()
print(p)

#with directlabels
dev.new()
direct.label(p)

Giving two different dataframes may causes the trouble, but I want to give separate data because data for contour in my work is relatively large comparing that for point plot.

Thanks for your help!

Answer 1

I am not 100% sure, but it seems that the problem is with how direct.label treats your first ggplot(NULL) call. Most likely it looks there for the required aesthetics, but not able to find them.

Here's how you can fix that:

pp0 <- ggplot(dat0, aes(x=x, y=y, z=z)) + geom_point()
pp <- pp0 + stat_contour(data=z.cubic, aes(x=x, y=y, z=z, colour=..level..))

and now both print(pp) and direct.label(pp) work as expected.

Update

Browsing the source, I found a way to fix the issue by adding the following line right before the last one in direct.label.ggplot : dlgeom$mapping <- c(dlgeom$mapping, L$mapping) .

Update 2

Toby Hocking (package maintainer) answered my message and, as it turns out, the package has indeed been updated to version directlabels_2014.6.13 on R-Forge, which is correctly pointed out by @user3357659. In fact, the idea I'm proposing here as a workaround for an outdated version directlabels_2013.6.15 has been already implemented there.

Answer 2

将您的直接标签升级到R-Forge版本

install.packages("directlabels", repos="http://r-forge.r-project.org")