在R - 行中的ggmap对象上绘制geom_segment不显示

Question

我想geom_segment在我的ggmap对象上绘制线条(准确地说:元素)(ggplot2据我所知,这是一个对象).

我使用以下代码:

library(ggmap)

mapImageData <- get_map(location = c(lon = (16.8 + ( 17.2-16.8)/2), 
                                     lat = (51 + (51.2-51)/2)),
                        color = "color",
                        source = "google",
                        maptype = "roadmap",
                        zoom = 11)

ggmap(mapImageData, extent = "device", ylab = "Latitude", xlab = "Longitude") + 
geom_segment(aes(x = 51, y = 16.8, xend = 51.2, yend = 17.2))

正在绘制一张清晰的地图:

但没有出现(从geom_segment)线.我究竟做错了什么？

Answer 1

纬度值对应于y值,经度对应x值.所以你必须改变x和y值geom_segment().

ggmap(mapImageData, extent = "device", ylab = "Latitude", xlab = "Longitude") + 
      geom_segment(aes(y = 51, x = 16.8, yend = 51.2, xend = 17.2))