R geom_point and ggmap, locations

Question

My goal is to make a map and put locations on that map. It would be similar to this R geom_point and ggmap but I can get the map, but having a hard time even getting the points to show up.

Here is the code I am using.

require(ggmap)
library(ggmap)
pp<- data.frame(lat=c(48.8535, 48.85418333, 48.86253333, 48.86373333, 48.86698333, 48.87033333,                 48.87281667, 48.86993333, 48.87718333, 48.86251667, 
48.85313333, 48.89153333, 48.88231667, 48.84368333, 48.84221667, 48.84473333, 48.8335,   48.86961667, >48.84681667), lon=c(-122.5735333, -122.54085, -122.5142667,
-122.4969667, -122.4857333, -122.4646, -122.44245, -122.4372167, -122.4128167, -122.4298,     -122.48205, -122.40875, -122.4423833, -122.55515, -122.5196667, -122.52105
, -122.5086333, -122.4067667, -122.4358833))
tenmile <- get_map(location = c(lon = -122.486328, lat = 48.862813),
    color = "color",
    source = "google",
    maptype = "roadmap",
    zoom = 12)
ggmap(tenmile,
extent = "device",
ylab = "Latitude",
xlab = "Longitude")
p<- ggmap(tenmile) + geom_point(data=pp, aes(x=lon, y=lat), color="red", size=30, alpha=0.5)  

Answer 1

I think your only problem is that you're not assigning your initial map to an object. Try this:

# Assign to variable
tenmile.map <- ggmap(tenmile,
      extent = "device",
      ylab = "Latitude",
      xlab = "Longitude")
# Then add the points to the base map you created.
p <- tenmile.map + geom_point(data=pp, aes(x=lon, y=lat),
                              color="red", size=30, alpha=0.5)  
p

If you want you could combine these, but you still have to do all your map specifications:

all.in.one <- ggmap(tenmile,
      extent = "device",
      ylab = "Latitude",
      xlab = "Longitude") + 
  geom_point(data=pp, aes(x=lon, y=lat),
                          color="red", size=30, alpha=0.5)  
all.in.one

One last comment: there are very small differences between library() and require(), but they both load the package and you only need to use one of them. Lots of details in this question if you're interested.