control of legends in GGplot 2

Question

I want to plot a data.frame, but on the legends the size is added. How do i control the size of the dots without adding size to the legends?

df1 <- data.frame(name = c("peter", "peter", "peter", "peter", "jacob", "jacob"),
        test =c(10,8,4,2,7,5),
         something =c(100,80,40,20,77,55)
        )

df2 <- data.frame(name = c("Greg", "Lisa"),
              test =c(11,3.5),
              something =c(102,35)
             )

ggplot(df1, aes(x=test, y=something, color= name,size = 3)) +
  geom_point()+
 geom_point(data=df2, aes(x=test, y=something, color= name, size=7))

Answer 1

You can just specify size in geom_point() itself:

library(ggplot2)

df <- data.frame(name = c("peter", "peter", "peter", "peter", "jacob", "jacob"),
                 test =c(10,8,4,2,7,5),
                 something =c(100,80,40,20,77,55)
)


ggplot(df, aes(x=test, y=something, color= name)) +
    geom_point(size = 3)

Update

In case you need all your point sizes to be 3 instead of just in this one call to geom_point(), you can just update the default size:

ggplot(df, aes(x=test, y=something, color= name)) +
    geom_point()

update_geom_defaults("point", list(size = 3))

ggplot(df, aes(x=test, y=something, color= name)) +
    geom_point()

Update 2:

In the updated question, you can still specify size per geom_point() call, so long as you put it outside the aes() wrapper:

ggplot(df1, aes(x=test, y=something, color= name)) +
    geom_point(size = 3)+
    geom_point(data=df2, aes(x=test, y=something, color= name), size=7)