将文本框添加到地图

Question

我正在使用ggmap绘制航点路线。

我需要在左上角的地图中添加一个文本框，其中包含代表每个航路点的名称向量。

没有关键字，只有文字的传说。做这个的最好方式是什么？我读过关于注释和传说但不确定这是最好的方法。

library(qmap)

names<-c("Name1","Name2", "Name3")

ggm <- qmap(location=map.centre,zoom = 15, maptype = 'road')  

  ggm +
    geom_path(data=coords,aes(x=startLon,y=startLat),color="blue",size=2)+
    geom_point(data=way.points,aes(x=as.numeric(X2),y=as.numeric(X1)),
               size=10,color="yellow")+
    geom_text(data=way.points,
              aes(x=as.numeric(X2),y=as.numeric(X1), label=seq_along(X1)))

Answer 1

这是来自http://bcb.dfci.harvard.edu/~aedin/courses/R/CDC/maps.html，但它使用形状，颜色和文字在右上角显示了一个合适的图例。如果您可以为您提供数据，可以根据您的具体需求进行定制。

library(ggmap) # for crime data for the example
library(qmap)

data(crime)

violent_crimes <- subset(crime, offense != "auto theft" & offense != 
    "theft" & offense != "burglary")

# rank violent crimes
violent_crimes$offense <- factor(violent_crimes$offense, levels = c("robbery", 
    "aggravated assault", "rape", "murder"))

# restrict to downtown
violent_crimes <- subset(violent_crimes, -95.39681 <= lon & lon <= 
    -95.34188 & 29.73631 <= lat & lat <= 29.784)

HoustonMap <- qmap('houston', zoom = 14,color = 'bw', legend = 'topright')
HoustonMap + geom_point(aes(x = lon, y = lat, 
                            size = offense,colour = offense), 
                            data = violent_crimes )