To change the color legend element border using ggplot2, we can use theme function where can put color in legend.key argument to desired color with element_rect.
For Example, if we have a data frame called df that contains three columns say X and Y and F where X and Y are numerical and F is categorical then we can create scatterplot between X and Y with blue color of legend element border by using the command given below −
ggplot(df,aes(IV,DV))+geom_point(aes(colour=factor(Class)))+theme(legend.key=element_rect(colour="red"))
Following snippet creates a sample data frame −
IV<-rpois(20,5) DV<-rpois(20,5) Class<-sample(c("I","II","III"),20,replace=TRUE) df<-data.frame(IV,DV,Class) df
The following dataframe is created
IV DV Class 1 4 4 III 2 4 5 III 3 3 4 I 4 3 8 I 5 3 3 II 6 7 7 I 7 5 4 II 8 3 4 III 9 1 5 II 10 6 8 II 11 3 3 II 12 4 5 II 13 5 8 I 14 2 2 I 15 6 6 III 16 6 4 II 17 1 3 I 18 4 5 I 19 6 7 II 20 7 3 III
To load ggplot2 package and create scatterplot between IV and DV with points color based on values in Class on the above created data frame, add the following code to the above snippet −
IV<-rpois(20,5) DV<-rpois(20,5) Class<-sample(c("I","II","III"),20,replace=TRUE) df<-data.frame(IV,DV,Class) library(ggplot2) ggplot(df,aes(IV,DV))+geom_point(aes(colour=factor(Class)))
If you execute all the above given snippets as a single program, it generates the following Output −
To create scatterplot between IV and DV with points color based on values in Class having legend borders in red on the above created data frame, add the following code to the above snippet −
IV<-rpois(20,5) DV<-rpois(20,5) Class<-sample(c("I","II","III"),20,replace=TRUE) df<-data.frame(IV,DV,Class) library(ggplot2) ggplot(df,aes(IV,DV))+geom_point(aes(colour=factor(Class)))+theme(legend.key=element_rect(colour="red"))
If you execute all the above given snippets as a single program, it generates the following Output −