Span argument not working on graph on ggplot2

Question

I have a plot and I wanted to change the span argument, but I don't see a difference in my lines.My observations are more than 1000 in each of the data.

I used this code:

ggplot(data, aes(x=, y=)) + geom_smooth(aes(color="KHRC"),se = FALSE, span = 0.3)+
  geom_smooth(data=GO1,aes(color="GO1"),se = FALSE, span = 0.3)+
  geom_smooth(data=GO2,aes(color="GO2"),se = FALSE, span = 0.3)+
  geom_smooth(data=GO4,aes(color="GO4"),se = FALSE, span = 0.3)+
  geom_smooth(data=GO3,aes(color="GO3"),se = FALSE, span = 0.3)+
  geom_smooth(data=GO6,aes(color="GO6"),se = FALSE, span = 0.3)+
  scale_x_datetime(limits = c(ymd_hms("2016-11-05 09:00:00"), ymd_hms("2016-11-07 00:00:00")))+
  labs(color="ID")+
  ggtitle("x vs y ")

Suggestions on how to fix the span will be great.Thank you.

Answer 1

Here is a simple, reproducible example of geom_smooth using the span parameter with the built-in iris dataset. This may help get you started troubleshooting your own implementation. As you can see below, changing the span from 0.5 to 0.95 functions as expected. Unfortunately it is not clear why it's not working for you, because we don't have your dataset to test it out.

library(ggplot2)

p1 = ggplot(iris, aes(x=Sepal.Width, y=Sepal.Length, colour=Species)) +
     geom_point(size=2, alpha=0.5, shape=20) +
     geom_smooth(method="loess", se=FALSE, span=0.5) +
     labs(title="Span = 0.5")   

p2 = ggplot(iris, aes(x=Sepal.Width, y=Sepal.Length, colour=Species)) + 
     geom_point(size=2, alpha=0.5, shape=20) +
     geom_smooth(method="loess", se=FALSE, span=0.95) +
     labs(title="Span = 0.95")

library(gridExtra)
ggsave("geom_smooth.png", arrangeGrob(p1, p2, ncol=2), width=9, height=4, dpi=150)