Geom_smooth not appearing in simple plot

Question

ggplot(R3L12, aes(x=Time, y=HeartRate)) +
  geom_point() +
  geom_smooth()

This is the output of dput(head(R3L12, 20))

structure(list(Date = c("2015-05-23", "2015-05-23", "2015-05-23", 
"2015-05-23", "2015-05-23", "2015-05-23", "2015-05-23", "2015-05-23", 
"2015-05-23", "2015-05-23", "2015-05-23", "2015-05-23", "2015-05-23", 
"2015-05-23", "2015-05-23", "2015-05-23", "2015-05-23", "2015-05-23", 
"2015-05-23", "2015-05-23"), Time = c("07:25:00", "07:40:00", 
"07:45:00", "09:10:00", "11:45:00", "11:55:00", "12:05:00", "12:35:00", 
"12:45:00", "13:30:00", "13:40:00", "13:45:00", "13:55:00", "14:00:00", 
"14:05:00", "14:10:00", "14:20:00", "14:25:00", "14:30:00", "14:35:00"
), Turtle = structure(c(3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L), .Label = c("R3L1", "R3L11", 
"R3L12", "R3L2", "R3L4", "R3L8", "R3L9", "R4L8", "R8L1", "R8L4", 
"R8NAT123"), class = "factor"), HeartRate = c(7.56457, 6.66759, 
17.51107, 9.72277, 19.44553, 13.07674, 28.115, 14.99467, 17.16947, 
40.40479, 37.76642, 29.98933, 43.5329, 49.61471, 47.74245, 44.10196, 
21.35316, 44.68609, 49.25255, 29.98933)), row.names = c(NA, 20L
), class = "data.frame")

Here is the code of a plot I tried to create. I'm confused because when I plot it, the geom_smooth doesn't show up. Time is a factor variable, and HeartRate is a double. I'm new to R so let me know if you need more information!

enter image description here

Your `Time` value is not in a numerical format. Maybe you should check its format and convert it either as a numerical or a date format. If this is not working, please provide a reproducible example of your dataset. — dc37, Feb 28 '20 at 14:24
@dc37 I'm not exactly sure how I would do that since my data set is very big. — Cassidy, Feb 28 '20 at 14:34
Can you post sample data? Please edit **the question** with the output of `dput(head(R3L12, 20))`. If your data set is very big, like you say, this will select only the first 20 rows. — Rui Barradas, Feb 28 '20 at 14:35
`ggplot(R3L12, aes(x=as.numeric(Time), y=HeartRate)) + geom_point() + geom_smooth()` ? — cbo, Feb 28 '20 at 14:35

Dimitrios Zacharatos · Accepted Answer · 2020-02-29T11:02:05.930

This is a different solution in two ways. (1) It redefines aes inside geom smooth. (2) It treats the time character values as ordinal, and thus it treats different measurements as equidistant. Depending on your hypotheses, this is not always the best thing to do. But sometimes it may be exactly what you want.

R3L12<-structure(list(Date=c("2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23","2015-05-23"),
                      Time=c("07:25:00","07:40:00","07:45:00","09:10:00","11:45:00","11:55:00","12:05:00","12:35:00","12:45:00","13:30:00","13:40:00","13:45:00","13:55:00","14:00:00","14:05:00","14:10:00","14:20:00","14:25:00","14:30:00","14:35:00"),
                      Turtle=structure(c(3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L,3L),
                                         .Label = c("R3L1","R3L11","R3L12","R3L2","R3L4","R3L8","R3L9","R4L8","R8L1","R8L4","R8NAT123"),class="factor"),
                      HeartRate=c(7.56457,6.66759,17.51107,9.72277,19.44553,13.07674,28.115,14.99467,17.16947,40.40479,37.76642,29.98933,43.5329,49.61471,47.74245,44.10196,21.35316,44.68609,49.25255,29.98933)),row.names=c(NA,20L),class="data.frame")

ggplot(R3L12,aes(x=Time,y=HeartRate)) +
  geom_point() +
  geom_smooth(aes(x=as.numeric(factor(Time)),y=HeartRate))

This changes the time values into NA. Time is in the format H:M:S — Cassidy, Feb 28 '20 at 14:42
This answer worked the best and was very simple to understand and replicate! Thank you for your help. — Cassidy, Feb 29 '20 at 14:54

score 1 · Answer 2 · answered Feb 28 '20 at 15:23

If times are unevenly spaced, as this is the case, and you want distance between x-axis points to reflect the actual time that is elapsed, you must convert your time variable into a POSIXct object. This may also change the way the smoothing line is shown, because the density of the points will change over the x-axis.

R3L12$time.posix <- as.POSIXlt(paste(R3L12$Date, R3L12$Time), format="%Y-%m-%d %H:%M:%S")
ggplot(R3L12, aes(x=time.posix, y=HeartRate)) +
   geom_point() +
   geom_smooth()

dc37 · Answer 3 · 2020-02-28T16:15:02.463

1

An alternative solution using lubridate package:

library(lubridate)
library(scales)
library(dplyr)
library(ggplot2)
df %>% 
  mutate(DateTime = ymd_hms(paste(Date, Time))) %>%
  ggplot(aes(x= DateTime, y = HeartRate))+
  geom_point()+
  geom_smooth()+
  scale_x_datetime( breaks=date_breaks("1 hour"), labels = date_format("%H:%M"))

edited Feb 28 '20 at 16:15

answered Feb 28 '20 at 15:25

dc37

15,840
4
15
32

Geom_smooth not appearing in simple plot

3 Answers3

Linked