Combine Two ggplot2 Plots from Different Data Frames in R (Example)
In this article you’ll learn how to draw a ggplot2 plot based on several different data sources in the R programming language.
Table of contents:
Let’s do this…
Example Data, Add-On Packages & Default Plot
Consider the following example data:
data1 <- data.frame(x = 1:5, # Create first data frame y = 1:5) data1 # Print first data frame # x y # 1 1 1 # 2 2 2 # 3 3 3 # 4 4 4 # 5 5 5 data2 <- data.frame(x = 2:6, # Create second data frame y = 8:4) data2 # Print second data frame # x y # 1 2 8 # 2 3 7 # 3 4 6 # 4 5 5 # 5 6 4 |
The previous RStudio console output shows the structure of our example data sets – Both data frames contains two numeric columns with the variable names x and y.
If we want to use the functions of the ggplot2 package, we also have to install and load ggplot2:
install.packages("ggplot2") # Install ggplot2 package library("ggplot2") # Load ggplot2 package |
Now, we can move on to the example…
Example: Drawing ggplot2 Plot Based on Two Different Data Frames
This section shows how to use the ggplot2 package to draw a plot based on two different data sets.
For this, we have to set the data argument within the ggplot function to NULL. Then, we are specifying two geoms (i.e. geom_point and geom_line) and define the data set we want to use within each of those geoms.
ggp <- ggplot(NULL, aes(x, y)) + # Draw ggplot2 plot based on two data frames geom_point(data = data1, col = "red") + geom_line(data = data2, col = "blue") ggp # Draw plot |
Figure 1 visualizes the output of the previous R code – A ggplot2 graph created based on multiple different data matrices.
Video, Further Resources & Summary
If you need more information on the R programming codes of this article, you may watch the following video of my YouTube channel. In the video, I illustrate the content of this article.
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Furthermore, I can recommend having a look at some of the other tutorials of this homepage:
- Draw Unbalanced Grid of ggplot2 Plots
- Arrange List of ggplot2 Plots
- Add Common Legend to Combined ggplot2 Plots
- R Graphics Gallery
- The R Programming Language
Summary: In this article, I explained how to create a ggplot2 graph with two different data sets in the R programming language – a very nice method in case you want to add a new layer or series of data points to a ggplot2 plot. Let me know in the comments section, in case you have additional questions.
I’m Joachim Schork. On this website, I provide statistics tutorials as well as code in Python and R programming.
16 Comments. Leave new
Hi, how are you?
I need your help!
I have 2 data frame with 3 columns each one (with 264.000 rows). The columns “Id1” (first) and “Id2” (second) are the same in both files (.tsv).
I tried to merge the columns Id1 and Id2 for two files but this result in an error: cannot allocate vector of size 972.2 Mb in R.
I wanna plot (scatter plot) the numerical values in the third columns for the two different files: Val1 (third column for file 1) VS Val_1 (third column for file 2).
Can you help me please?
Hey Mauricio,
This sounds like a huge file! Do you really need all these data points or is it possible to make the file smaller before merging it?
You may have a look at this tutorial: https://statisticsglobe.com/r-error-cannot-allocate-vector-of-size-n-gb It gives some tips on how to handle the error message you are facing.
I hope that helps!
Joachim
Hello,
I have a problem. I am working on two NetCDF files and I plotted them separately without having any problems. When I was combining them in one by following your method, “Error in FUN(X[[i]], …) : object ‘x’ not found” – this error keeps coming. What should I do? I want to plot from multiple NetCDF files in a single plot. Not to mention, spatial references, units and resolutions are same in the every files.
Hi Sudipta,
Could you post your R code? It’s difficult to tell the problem without seeing it.
Thanks
Joachim
Your past saved me!
Could you explain how to add the legend to the figure?
I tried to add the legend but I could not do it.
Thanks
Hi Sael,
Thanks a lot, glad the tutorial helped!
One solution would be to add the aes() function to both geoms, i.e.
Note that this changes the colors to the default color palette of the ggplot2 package.
Regards
Joachim
I got blow error:
Error: Aesthetics must be either length 1 or the same as the data (5): y
I have used data1 having 5 rows and data2 having 8 rows, how to solve this issue. How can I plot data from two different files having different number of rows.
Hey Ramki,
I’m sorry for the late response, I just came back from holidays and did not have the chance to read your message earlier.
Are you still looking for a solution to this problem?
Regards
Joachim
Hello Joachim,
I have the same doubt that Ramki. I want plot using differents dataset having differents number of rows.
Hey Paulo,
Thank you for bringing this question up again. It has inspired me to create a new tutorial focusing on this topic.
You can find the tutorial here: https://statisticsglobe.com/draw-two-data-sets-different-sizes-ggplot2-plot-r
Regards,
Joachim
Thank you, Joachim. Helped me a lot. And as a free gift, you taught me to combine two data sets. It was just not to set a default data set in ggplot.
This is really great to hear Paulo, glad it helped! 🙂
Hello Joachim, I need your help. Do you know how to comine two pltos froms differents data frames (two different models of the library effects) For example:
library (nlme)
library (effects)
m1<- lme(log(Ara_Tot+1) ~ FOREST+log(Ara_Tot_m+1)+log(Prey_ChinchFit_Lepidop+1), data= REDV, random = ~1|ANIO, method ="REML")
eff_Forest<- effect("FOREST",m1, partial.residuals=TRUE)
plot(eff_Forest, smooth.residuals=FALSE,lty=1,lines=list(col="black",lwd=2), residuals.color="black",band.colors="black",band.line ="black",lwd=3, main="Spiders, Before b. pod", ylab="% of forest")
m2<- lme(log(Ara_Tot+1) ~ FOREST+log(Ara_Tot_m+1), data= PANV, random = ~1|ANIO, method ="REML")
eff_Forest<- effect("FOREST",m2, partial.residuals=TRUE)
plot(eff_Forest, smooth.residuals=FALSE,lty=1,lines=list(col="black",lwd=2), residuals.color="black",band.colors="black",band.line ="black",lwd=3, main="Spiders, Before b. pod", ylab="% of forest")
I want to show in one graphic both variables of these two differents models.
Could you help me??
Hey Silvana,
Are you looking for the points() function? Please have a look here for more details.
Regards,
Joachim
Thank you Joachim! I wil try, but I think effects library cannot run with this option!
Best regards, Silvana
It seems like you have used the plot function to draw your data before. I assume that the point function works as well, if the plot function works.
Regards,
Joachim