bob jones bob jones - 3 months ago 42
R Question

How to add labels to points conditionally in a city map using ggmap

I was trying to label points using name on the map conditionally for a city.

Data

name |s Latitude |s Longitude |s Frequency

Pelham Bay Park | 40.865556 | -73.808333 | 32

Greenbelt | 40.58846 | -74.139073 | 10

Van Cortlandt Park | 40.8978 | -73.8839 | 3

Flushing Meadows–Corona Park | 40.745833 | -73.844722 | 5

Central Park | 40.783333 | -73.966667 |22


Code

library(ggmap)
town <- get_map(location = "New York", zoom = 10)

mapPoints <- ggmap(town) +
geom_point(aes(x = work_count$Longitude, y = work_count$Latitude, size = work_count$Frequency), data = work_count, alpha = .5) +
geom_text(aes(label=ifelse(work_count$Frequency>quart(work_count$Frequency)[2],as.character(work_count$name),'')),hjust=0,vjust=0)

quart <- function(x) {
x <- sort(x)
n <- length(x)
m <- (n+1)/2
if (floor(m) != m) {
l <- m-1/2; u <- m+1/2
} else {
l <- m-1; u <- m+1
}
c(Q1=median(x[1:l]), Q3=median(x[u:n]))
}
mapPoints


I am getting the following error:
Error: Aesthetics must be either length 1 or the same as the data (5): label, x, y
Any help is appreciated

Answer

This seems to work.

work_count$lab <- ifelse(work_count$Frequency>quart(work_count$Frequency)[2],
  as.character(work_count$name), '')

mapPoints <- ggmap(town, 
                   base_layer = ggplot(work_count, 
                     aes(x = Longitude, y = Latitude))) +
  geom_point(aes(size = Frequency), 
             alpha = .5) +
  geom_text(aes(label = labels), 
            vjust = 0,
            hjust = 0)
mapPoints

enter image description here