Plotting Multiple Lines on Graph for Different groups in ggplot

Question

I am trying to edit a plot that I created in ggplot such that each facet shows 2 different lines overlapping (one for avg. actual run hours, one for avg. scheduled run hours) as well as display a legend to the right to indicate which line is actual vs. scheduled. I referenced the post here but was unable to get the solution to work in my case because I'm dealing with different columns that need to be overlapped, and not a group within one variable. Please note that the lines will be nearly identical in this case, but I have other use cases involving the same task where the lines will differ significantly - hence the request for help.

My data is listed below for reference:

structure(list(month_yr = c("2022-01", "2022-01", "2022-02", 
"2022-02", "2022-03", "2022-03", "2022-04", "2022-04", "2022-05", 
"2022-05", "2022-06", "2022-06", "2022-07", "2022-07", "2022-08", 
"2022-08", "2022-09", "2022-09", "2022-10", "2022-10", "2022-11", 
"2022-11", "2022-12", "2022-12", "2023-01", "2023-01", "2023-02", 
"2023-02"), plant_name = c("plant_f", "plant_s", "plant_f", "plant_s", 
"plant_f", "plant_s", "plant_f", "plant_s", "plant_f", "plant_s", 
"plant_f", "plant_s", "plant_f", "plant_s", "plant_f", "plant_s", 
"plant_f", "plant_s", "plant_f", "plant_s", "plant_f", "plant_s", 
"plant_f", "plant_s", "plant_f", "plant_s", "plant_f", "plant_s"
), avg_run_hours = c(15.0080608695652, 16.3453608247423, 14.7394112149533, 
16.1025555555556, 14.9570175438596, 15.7327777777778, 17.0074257425743, 
16.5604901960784, 16.989010989011, 16.3021296296296, 14.8100961538462, 
15.8714516129032, 16.5552083333333, 15.3971568627451, 16.2258771929825, 
14.2616279069767, 17.2556179775281, 14.3790350877193, 16.3594903846154, 
15.5988617886179, 14.4050925925926, 15.9334920634921, 14.3455056179775, 
16.6322935779817, 16.6958762886598, 17.1025714285714, 16.046875, 
16.8408695652174), avg_sched_run_hours = c(15.0267043478261, 
16.4351340206186, 15.0025140186916, 16.2041555555556, 14.8281578947368, 
15.9119814814815, 17.1840099009901, 16.7646666666667, 17.0109340659341, 
16.4446388888889, 14.7679615384615, 16.1768790322581, 16.3242083333333, 
15.7033333333333, 16.343701754386, 14.5158139534884, 17.4342921348315, 
14.5827280701754, 16.4562692307692, 15.4149105691057, 14.2729537037037, 
16.1438253968254, 14.3073595505618, 16.7186330275229, 16.6436082474227, 
17.0332952380952, 16.3137916666667, 16.9656739130435)), class = c("grouped_df", 
"tbl_df", "tbl", "data.frame"), row.names = c(NA, -28L), groups = structure(list(
    month_yr = c("2022-01", "2022-02", "2022-03", "2022-04", 
    "2022-05", "2022-06", "2022-07", "2022-08", "2022-09", "2022-10", 
    "2022-11", "2022-12", "2023-01", "2023-02"), .rows = structure(list(
        1:2, 3:4, 5:6, 7:8, 9:10, 11:12, 13:14, 15:16, 17:18, 
        19:20, 21:22, 23:24, 25:26, 27:28), ptype = integer(0), class = c("vctrs_list_of", 
    "vctrs_vctr", "list"))), class = c("tbl_df", "tbl", "data.frame"
), row.names = c(NA, -14L), .drop = TRUE))

Code I used to create the image below:

hours_by_plant <-
    ggplot(so_run_hour_stats, aes(x=month_yr, y=avg_sched_run_hours, group=1)) + geom_point() +
    geom_line(color="red") + xlab("Month of Year") + ylab("Avg Run Hours") +
    ggtitle("Avg Plant Run Hours by Month from 01/2022 - 02/2023") + theme_classic() +
    facet_wrap(~plant_name)

hours_by_plant <- hours_by_plant + theme(plot.title = element_text(hjust = 0.5))

score 1 · Accepted Answer · answered Feb 18 '23 at 08:58

This type of problems generally has to do with reshaping the data. The format should be the long format and the data is in wide format. See this post on how to reshape the data from wide to long format.

I also transform the dates into real date objects and edit the avg_* columns after pivoting.

You can set the x axis date breaks to different values if you want to, for instance, to 1 month.

suppressPackageStartupMessages({
  library(dplyr)
  library(tidyr)
  library(ggplot2)
})

so_run_hour_stats %>%
  pivot_longer(cols = starts_with("avg"), names_to = "Average") %>%
  mutate(month_yr = as.Date(paste0(month_yr, "-01")),
         Average = sub("avg_", "", Average),
         Average = gsub("_", " ", Average)) %>%
  ggplot(aes(month_yr, value, colour = Average)) +
  geom_line() +
  geom_point(color = "black") +
  scale_x_date(date_breaks = "3 months", date_labels = "%Y-%m") +
  scale_color_manual(values = c("red", "blue")) +
  facet_wrap(~ plant_name) +
  theme_classic() +
  theme(axis.text.x = element_text(angle = 60, vjust = 1, hjust = 1))

^{Created on 2023-02-18 with reprex v2.0.2}

Plotting Multiple Lines on Graph for Different groups in ggplot

1 Answers1