沒有非缺失參數MIN和MAX

Question

我使用R鍵在地圖上繪製一些座標，使用下面的代碼：

library(ggplot2) 
library(ggmap) 

smalloperations <- read.csv("S:/smalloperations.csv", na.strings=c("","NA")) 

lon <- c(smalloperations$target.longitude) 
lat <- c(smalloperations$target.latitude) 
df <- as.data.frame(cbind(lon,lat)) 

# getting the map 
mapgilbert <- get_map(location = c(lon = mean(df$lon), lat = mean(df$lat)), 
zoom = 1, maptype = "satellite", scale = 2) 

# plotting the map with some points on it 
ggmap(mapgilbert) + 
geom_point(data = df, aes(x = lon, y = lat, fill = "red", alpha = 0.8), size 
= 5, shape = 21) + 
guides(fill=FALSE, alpha=FALSE, size=FALSE) 

當我運行此代碼，我得到這樣的警告：

警告消息： 1：在min（x）中：沒有非缺少參數min;返回Inf 2：在max（x）中：沒有非缺失參數爲max;返回-Inf 3：在min（x）中：沒有非缺少參數min;返回Inf 4：在max（x）中：沒有非缺失參數爲max;返回-Inf

然後代碼顯示座標，但在背景中沒有地圖。我環顧四周，這個錯誤發生在其他人身上，但我看到的解決方案似乎並不適合我的具體問題。 我正在使用this dataset from kaggle的較小的已清理版本，該版本在我使用的目標經度和緯度上沒有空值或NA，並且根本沒有NA。

我的數據結構：

'data.frame': 13 obs. of 20 variables: 
$ mission.id     : int 1 2 3 4 5 6 7 8 9 10 ... 
$ mission.date    : Factor w/ 1 level "15/08/1943": 1 1 1 1 1 1 1 
1 1 1 ... 
$ theater.of.operations  : Factor w/ 4 levels "CBI","ETO","MTO",..: 3 4 
3 3 4 4 4 4 3 3 ... 
$ country     : Factor w/ 2 levels "GREAT BRITAIN",..: 2 2 2 
2 2 2 2 2 2 2 ... 
$ air.force     : Factor w/ 4 levels "10 AF","12 AF",..: 2 3 2 
2 3 3 3 3 2 2 ... 
$ aircraft.series   : Factor w/ 4 levels "A36","B17","B24",..: 1 3 
1 1 3 3 3 2 1 1 ... 
$ mission.type    : Factor w/ 4 levels "OBJECTIVE BOMBING",..: 4 
1 4 4 1 1 3 1 4 4 ... 
$ takeoff.base    : Factor w/ 2 levels "PONTE OLIVO AIRFIELD",..: 
1 2 1 1 2 2 2 2 1 1 ... 
$ takeoff.location   : Factor w/ 2 levels "SICILY","UNKNOWN": 1 2 1 
1 2 2 2 2 1 1 ... 
$ target.id     : Factor w/ 6 levels "16140","3735",..: 4 6 5 1 
6 6 6 6 3 1 ... 
$ target.country    : Factor w/ 5 levels "BURMA","GERMANY",..: 3 4 
3 3 5 4 4 4 3 3 ... 
$ target.city.or.area  : Factor w/ 10 levels "BERLIN","COSENZA",..: 10 
6 2 3 5 4 8 8 9 3 ... 
$ target.type    : Factor w/ 5 levels "AIRDROME","CITY AREA",..: 
4 3 4 4 5 4 4 1 4 4 ... 
$ target.industry   : Factor w/ 3 levels "ARMAMENT AND ORDNANCE 
PLANTS",..: 3 3 3 3 3 3 3 3 3 1 ... 
$ target.priority   : int 9 1 9 9 1 1 1 1 9 9 ... 
$ target.latitude   : num 38.22 -7.17 39.27 38.43 -1.12 ... 
$ target.longitude   : num 15.4 147 16.2 15.9 103.9 ... 
$ altitude..hundreds.of.feet.: int 139 44 139 139 60 35 70 40 139 139 ... 
$ source.id     : Factor w/ 9 levels "11287","11326",..: 9 8 9 
9 3 7 1 2 9 9 ... 
$ bomb.type     : Factor w/ 2 levels "HIGH EXPLOSIVES",..: 1 1 
1 1 1 1 1 1 1 1 ... 

Answer 1

變焦3-20 http://stat405.had.co.nz/ggmap.pdf整數使用的是1