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Handling Multiple Y-Axis in ggplot2 with Different Scales for Time Series Data

👀 Views: 70 đŸ’Ŧ Answers: 1 📅 Created: 2025-08-28
ggplot2 data-visualization time-series R

I'm dealing with Hey everyone, I'm running into an issue that's driving me crazy. I've looked through the documentation and I'm still confused about I'm trying to create a time series plot in `ggplot2` where I need to display two different metrics on separate y-axes... The first metric is revenue, and the second one is customer counts, both plotted against the same date range. However, I'm getting unexpected results when I attempt to overlay them using the `sec.axis` feature. Here's the code I've been using: ```R library(ggplot2) library(dplyr) # Sample data set.seed(123) date_seq <- seq(as.Date('2023-01-01'), as.Date('2023-12-31'), by='month') revenue <- rnorm(length(date_seq), mean=10000, sd=2000) customers <- rnorm(length(date_seq), mean=500, sd=100) data <- data.frame(date=date_seq, revenue=revenue, customers=customers) # Attempt to create the plot p <- ggplot(data, aes(x=date)) + geom_line(aes(y=revenue), color='blue') + scale_y_continuous(name='Revenue', sec.axis=sec_axis(~./20, name='Customer Count')) + geom_line(aes(y=customers * 20), color='red') + labs(title='Revenue and Customer Count Over Time', x='Date') print(p) ``` The issue I'm encountering is that the second y-axis (for customer counts) appears to be misaligned, and the scaling doesn't seem to reflect the actual data. I want the customer counts to display correctly in relation to the revenue on the primary axis. I tried adjusting the `sec.axis` transformation but still see the plotted line not matching my expectations. Additionally, I received a warning message: `Warning: Transformation introduced infinite values in continuous y-axis`. It seems to indicate that the scaling is causing issues. Is there a proper approach to handle this scenario in `ggplot2`? Any suggestions or best practices would be greatly appreciated! My development environment is macOS. Is there a better approach? I'm using R latest in this project. For context: I'm using R on Windows 11. What would be the recommended way to handle this? Thanks for taking the time to read this!