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rggplot2trend

trend line for a whole group - R

I'm trying to make a trend line for the total of the groups, but it draws a trend line for EACH group. The same code I'm using I put it here (with iris dataset):

iris %>%
  mutate(id = as.numeric(rownames(iris))) %>%
  select(id, Sepal.Length, Sepal.Width, Petal.Length) %>%
  reshape(., direction = "long", varying = names(.)[2:4], v.names = "valor", idvar = c("id"), timevar = "tipo", times= colnames(.[2:4])) %>%
  ggplot(aes(x=id, y=valor, fill=tipo)) +
  geom_area() +
  geom_smooth(method = "lm")

An image of the output of my dataframe (without geom_smooth() line)

enter image description here

I have tried adding a trend line with:

  geom_smooth(method = "lm")

But it adds a trend line for each group, when I just need one for the total.

Solution

  • Set the aes mapping for each individual geom:

    iris %>%
  mutate(id = rownames(iris)) %>%
  select(id, Sepal.Length, Sepal.Width, Petal.Length) %>%
  reshape(., direction = "long", varying = names(.)[2:4], v.names = "valor", idvar = c("id"), timevar = "tipo", times= colnames(.[2:4])) %>%
  mutate(id = as.numeric(id)) %>%
  ggplot() +
  geom_area(aes(x=id, y=valor, fill=tipo)) +
  geom_smooth(aes(x=id, y=valor), method = "lm")

    (I needed to add an additional mutate to change id to numeric to get your code to work)