“non-numeric argument to binary operator” when using geom_point + aes function

1
votes

I am trying to plot on map "UKmap" the amount of vessels "n" in each administrative port "AdminPort" in the UK, in my code I have made size equal to n (the number of vessels) so the points plotted on the map depend on the # of vessels. Even though n is a column of numbers I keep getting the error message:

"Error in UKmap + geom_point(aes(x = Longitude, y = Latitude), size = 4, : non-numeric argument to binary operator
In addition: Warning message: Incompatible methods ("Ops.raster", "+.gg") for "+" "

What am I doing wrong? I have added my code and the 30x4 tibble (AdminPortCLL) below.

# A tibble: 30 x 4
       lon   lat AdminPort       n
     <dbl> <dbl> <chr>       <int>
 1 -2.10    57.1 ABERDEEN       70
 2 -4.63    55.5 AYR            77
 3 -5.93    54.6 BELFAST       187
 4 -3.52    50.4 BRIXHAM       184
 5 -2.96    57.7 BUCKIE         69
 6 -5.61    55.4 CAMPBELTOWN    97
 7 -2.09    55.9 EYEMOUTH       73
 8 -3.01    53.9 FLEETWOOD      92
 9 -2.02    57.7 FRASERBURGH   120
10 -0.0736  53.6 GRIMSBY        56
# ... with 20 more rows

UKmap +
  geom_point(aes(x = Longitude, y = Latitude), 
             size =  n, data = AdminPortCLL) + 
  theme(legend.position = "top")
1
rggplot2
You probably want size = n inside the aes – Richard Telford
I still get the same error message when I move the size inside aes. – Jamiet9850
what is UKmap - problem is not reproducible without this. Does your code work if you replace UKmap with ggplot()? – Richard Telford

1 Answers

0
votes

Assuming you are using ggmap.... Your UKmap may still be just an image. Before adding the points, convert it to a ggmap object: 

UKmap <- ggmap(UKmap)

Also, you need to use the column names that are in the AdminPortCLL tibble:

UKmap +
  geom_point(aes(x = lon, y = lat), 
             size =  n, data = AdminPortCLL) + 
  theme(legend.position = "top")