Error: Aesthetics must be either length 1 or the same as the data (4)

Question

I am working with ggmap. the goal is to plot coordinate points on the map and label the points with their names. I have data frame with name, longitude and latitude.

The data looks like:

df <- structure(list(Station.Area = c("Balbriggan", "Blanchardstown", 
"Dolphins Barn", "Donnybrook", "Dun Laoghaire", "Finglas"), Latitude = c(53.608319, 
53.386813, 53.333532, 53.319259, 53.294396, 53.390325), Longitude = c(-6.18208, 
-6.377197, -6.29146, -6.232017, -6.133867, -6.298401)), .Names =c("Station.Area","Latitude", "Longitude"), row.names = c(NA, 6L), class = "data.frame")

The code I wrote is as below:

library(ggmap)
library(ggplot2)

dub_map <- get_map(location = "Dublin", zoom = "auto", scale="auto", crop = TRUE, maptype = "hybrid")

ggmap(dub_map) +`
    geom_point(data = df, aes(x = Longitude, y = Latitude, 
              fill = "green", alpha =` `0.8, size = 5, shape = 21)) +`
guides(fill=FALSE, alpha=FALSE, size=FALSE)+
geom_text(label=df$Station.Area)+
scale_shape_identity()

But i am getting

Error: Aesthetics must be either length 1 or the same as the data (4): label

I have tried to put various aesthetics in geom_text like size,color,x & Y but it still gives out same error.

Am i doing it correctly for my goal? Please help.

Getting this without geom_text now I just want to label the points

Answer 1

There are a couple of things not quite right in your code.

For the geom_point you only want the x and y in your aes. The other arguments should be outside, giving

geom_point(data = df, aes(x = Longitude, y = Latitude), 
                  fill = "green", alpha =0.8, size = 5, shape = 21)

Also the label for the geom_text should be inside aes. However, as there is no data, x or y at a higher level, then geom_text will not find the label variable or the positions of where to place the labels. So you also need to include these in the call

geom_text(data=df, aes(x = Longitude, y = Latitude, label=Station.Area))

However, you can omit some of this repetition by using the base_layer argument of ggmap:

ggmap(dub_map, 
      base_layer = ggplot(data=df, aes(x = Longitude, 
                                       y = Latitude, 
                                       label=Station.Area))) +
      geom_point(fill = "green", alpha =0.8, size = 5, shape = 21) +
      geom_text()