在R中绘制地图上的每个坐标

Question

我在R中绘制纬度和经度（总共300个）但是我的代码只在地图上显示一个点。任何人都可以告诉我如何可视化地图上的所有点？ 我的代码如下所述;

 library("ggmap")
 library(maptools)
 library(maps)


 visit.x <- Nlongs
 visit.y <- Nlats

 mp <- NULL
 mapWorld <- borders("world", colour="gray50", fill="gray50") 
 # create a layer of borders
 mp <- ggplot() +   mapWorld
 #Now Layer the cities on top
  mp <- mp+ geom_point(aes(x=visit.x, y=visit.y) ,color="blue", size=3) 
  mp



 > Nlongs
   [1] 5.010786 5.010823 5.010862 5.010823 5.010873 5.010872 5.010873 
   5.010823 5.010872

  > Nlats
   [1] 47.29396 47.29397 47.29398 47.29397 47.29396 47.29396 47.29396 
   47.29397 47.29393

Answer 1

这是正确的实施。您需要提供/读入300个访问过的城市的名称列表到visited向量。我在这里提供3。

visited <- c("Dijon", "Cambridge", "Los Angeles")
ll.visited <- geocode(visited)
ll.visited


mp <- NULL
mapWorld <- borders("world", colour="gray50", fill="gray50") 

# provide ll.visited data to ggplot
mp <- ggplot(ll.visited) + mapWorld

# assign x and y to correspond to lon and lat of ll.visited
mp <- mp + geom_point(aes(x=lon, y=lat), color="blue", size=3) 
mp