Plot latitude and longitude

问题

I'm trying to plot the latitude and longitude, but I'm getting an error message.

The code I'm using is the following

tweets <- searchTwitter('weather', n=1000,lang='en')
t <- twListToDF(tweets)
lat <- t[, c("latitude")]
lon <- t[, c("longitude")]
l.df <- data.frame(lat,lon)
l.na <- l.df[!is.na(l.df)]
require(ggplot2)
ggplot(l.na, aes(x=lon, y=lat,)) + geom_point(size=1.9, alpha=.02)

The error message is the following:

Error: ggplot2 doesn't know how to deal with data of class character

The values I'm getting in l.na are the following:

[1] "61.22"         "54.55508056"   "37.57"         "-5.14"         "37.78678264"   "29.42989111"   "32.79755357"   "30.26960519"   "29.75523769"  
[10] "51.04839287"   "30.1774"       "44.34334946"   "49.89034914"   "34.05161048"   "41.88804564"   "32.72791305"   "51.52027778"   "-31.77"       

Any ideas why I'm getting the error message?

回答1:

Try converting the lat and lon columns into numeric.

l.df$lat <- as.numeric(l.df$lat)

l.df$lon <- as.numeric(l.df$lon)

l.na <- l.df[!is.na(l.df)]

Then apply the ggplot function:

ggplot(l.na, aes(x=lon, y=lat,)) + geom_point(size=1.9, alpha=.02)

来源：https://stackoverflow.com/questions/42462677/plot-latitude-and-longitude