向ggmake plot添加点时出错

Error in adding points to ggmake plot

我正在尝试使用 ggmake 创建一个地块,该地块已创建,但随后我想使用 geom_point 添加点,为此我给出了城市的经度和纬度但未能实现,因为一个错误,下面我粘贴了包含经度和纬度的代码和数据框。

City    Longitude   Latitude
Mastung 66.84691    29.4087
Khuzdaar    66.611691   27.812
Khaich  63.01475    26.156
Panjgore    64.112336   26.97524
Quetta  66.998734   30.1829713
Dera Bugti  69.159609   29.035158 
Kohlo   69.24901    29.8975
Kalat   66.5878 29.0303
Kharaan 65.4222 28.5812
Nooshki 66.0195 29.555

kl <- read.csv(file.choose())
map <- get_map(location=c(66.214995,28.538837), zoom=7) + geom_point(data =     
kl,aes(x =longitude,y = latitude,size =4),color='red')
Error:Error in Ops.raster(get_map(location = c(66.214995, 28.538837), zoom = 7),  
: operator not meaningful for raster objects

如何绘制这些点并消除此错误?

kl <- read.table(text='
City    longitude   latitude
"Mastung" 66.84691    29.4087
"Khuzdaar"    66.611691   27.812
"Khaich"  63.01475    26.156
"Panjgore"    64.112336   26.97524
"Quetta"  66.998734   30.1829713
"Dera Bugti"  69.159609   29.035158 
"Kohlo"   69.24901    29.8975
"Kalat"   66.5878 29.0303
"Kharaan" 65.4222 28.5812
"Nooshki" 66.0195 29.555
', header=T)

library(ggmap)

mp <- get_map(location=c(66.214995,28.538837), zoom=7) 
ggmap(mp) +
geom_point(data=kl, aes(x=longitude, y=latitude), color='red', size=4)