Improving resolution on geom_text entry in ggplot2 r

user_1392044 0
Viewed 8037

Any suggestions on how improve the resolution on the geom_text so that the resolution is comparable to that of the axis labels? Thanks

df <- data.frame("x" = c(1,2,3,4),"y" = c(15,19,35,47))

p<-ggplot(df,aes(x,y))
p<- p + geom_point(size=1)

p<- p + geom_smooth(method="lm", se=FALSE, formula=y~x)
p<- p + xlab("Better Resolution")
p<- p +ylab("Better Resolution")

p<- p +opts(axis.title.x = theme_text(family="Times",face="bold", size=25, colour = "Black",vjust=0)) 

p<- p +opts(axis.title.y = theme_text(family="Times",face="bold", size=25, angle =90, colour ="Black",vjust=0.4))

p<- p + geom_text(aes(x = 3.5, y = 37, label ="123456789"),size=12, parse = TRUE)
p

#The zoomed in text looks like this after saving using ggsave

enter image description here

#Information about my version of R and OS

sessionInfo()
R version 2.15.1 (2012-06-22)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

R.version
           _                            
platform       x86_64-apple-darwin9.8.0     
arch           x86_64                       
os             darwin9.8.0                  
system         x86_64, darwin9.8.0          
status                                      
major          2                            
minor          15.1                         
year           2012                         
month          06                           
day            22                           
svn rev        59600                        
language       R                            
version.string R version 2.15.1 (2012-06-22)
nickname       Roasted Marshmallows  

##############
#The actual code I am using looks like this:

#function that creates the line equation
lm_eqn = function(df){
m = lm(y ~ x, df)
eq <- substitute(italic(y) == a + b %.% italic(x)*","~~italic(r)^2~"="~r2,
list(a = format(coef(m)[1], digits = 2),
b = format(coef(m)[2], digits = 2),
r2 = format(summary(m)$r.squared, digits = 3)))
as.character(as.expression(eq))
}


#creates basic plot and adds a line
p<-ggplot(df, aes(x,y))
p<- p + geom_point(alpha=1/10, colour="blue", size=5)

#controls background colours
p<-p + theme_bw()

#adds the labels, titles and makes them pretty

p<- p + geom_smooth(method="lm", se=FALSE, formula=y~x,colour="black")
p<- p + xlab("Species similarity for site pair (Tsim variable 'a')")
p<- p +ylab("Trait similarity for site pairs (Tsim)")
p<- p +opts(title="Species vs. Trait combination similarity 2-5m")
p<- p +opts(plot.title = theme_text(family="Times",face="bold", size=18, colour =   "Black",vjust=1)) 
p<- p +opts(axis.title.x = theme_text(family="Times",face="bold", size=15, colour = "Black",vjust=0)) 
p<- p +opts(axis.title.y = theme_text(family="Times",face="bold", size=15, angle =90, colour =  "Black",vjust=0.4))

#adds the equation
p<- p + geom_text(aes(x = 0.015, y = 0.08, label = lm_eqn(df)),size=6,  family="Times",face="italic", parse = TRUE)

ggsave(p,file="tsim.a.0-2.pdf")
ggplot2 r
3 Answers

Using annotate() instead of geom_text() for single annotation on graph. Otherwise, ggplot() will try to draw the same text for each data point which results in weird resolution.

user_101976800

Echoing @RonnieZavata's answer above (which I think is the correct one for this question), geom_text can cause ggplot to write the same text multiple times in the same location, creating fuzzy-looking text in the output. However, using ggplot2::annotate(), which has similar syntax, allows you to print the annotation text only once, which makes the annotations as crisp as other text in the plot.

# load library
library(ggplot2)

# OP example up to adding text to plot
df <- data.frame("x" = c(1,2,3,4),"y" = c(15,19,35,47))

p <- ggplot(df, aes(x,y)) + 
  geom_point(size=1) +
  geom_smooth(method = "lm", se=FALSE, formula=y~x) + 
  xlab("Better Resolution") +
  ylab("Better Resolution")

# lousy resolution from geom_text

p + geom_text(aes(x = 3.5, y = 37, label ="123456789"),size=12, parse = TRUE)

# but fine resolution from `annotate()`
p + annotate("text", x = 3.5, y = 37, label ="123456789", size = 12)

It's interesting to me that in comments, some noted this might be specific to a particular OS or PDF viewer; Although the low resolution in the examples is apparent but subtle for me using Rstudio's graphics device, I searched this issue after running into a pretty extreme version of @Elizabeth's problem viewing a .pdf created with pdf() in Preview on macOS 12.5.

user_84009690
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