Plot geocode: ggmap error

Question

I want to visualize a dataframe with R and the ggmap package.

df:

| lon       | lat       |
|-----------|-----------|
| 6.585863  | 51.09021  |
| 8.682.127 | 50.11092  |
| 7.460.367 | 5.152.755 |

I created a map with

mapImageData <- get_googlemap(
+   "Germany", 
+   zoom=15
+ )

And then wanted to add the geocodes:

ggmap(mapImageData) +
+     geom_point(aes(x=lon, y=lat), data=df, colour="red", size=5)

But I get the error: Error: geom_point requires the following missing aesthetics: x, y

What am I doing wrong?

Answer 1

You have three problems:

1. More than one deicmal point in some values & decimal points probably not at the right place (see also my comment)
2. The map is centered on the wrong spot
3. The zoom level is to high

Let's fix this:

# Get the right data
ger <- read.table(text="lon lat
6.585863 51.09021
8.682127 50.11092
7.460367 51.52755", header = TRUE, strip.white = TRUE)

# Finding a good centerpoint
mean(ger$lon) # outcome: 7.576119
mean(ger$lat) # outcome: 50.90956

# Get the map; you might have to try several zoomlevels te get the right one
library(ggmap)
mapImageData <- get_googlemap(center = c(lon = 7.576119, lat = 50.90956), zoom=8)

# Plot the points on the map
ggmap(mapImageData) +
  geom_point(data=ger, aes(x=lon, y=lat), colour="red", size=6, alpha=.6)

The resulting map: