绘制 DataCamp 总部

在 R 中使用 leaflet 构建交互式地图

Rich Majerus

Vice President of Strategy & Planning, Queens University of Charlotte

绘制单点

# add marker layer to map
leaflet() %>% 
     addTiles() %>% 
     addMarkers(lng = -73.98575, 
                lat = 40.74856)

单个标记示例

提供标记数据
- 数值型数据框列
- 数值向量
addMarkers() 默认行为
- 居中到单个点
- 缩放以适配所有点

绘制多个点

dc_hq <- 
     tibble(
         hq  = c("DataCamp - NYC", "DataCamp - Belgium"),
         lon = c(-73.98575, 4.717863),
         lat = c(40.74856, 50.881363))
leaflet() %>% 
     addTiles() %>% 
     addMarkers(lng = dc_hq$lon, lat = dc_hq$lat)

多个标记示例

绘制多个点 II

# When piping a data frame into the leaflet function, R will search 
# for columns named lat/latitude and lon/lng/long/longitude  
dc_hq  %>% 
     leaflet() %>% 
     addTiles() %>% 
     addMarkers() 
Assuming 'lon' and 'lat' are longitude and latitude, respectively

多个标记示例

弹出框

leaflet() %>% 
     addTiles() %>% 
     addMarkers(lng = dc_hq$lon, lat = dc_hq$lat, 
               popup = dc_hq$hq)

带弹出框的标记示例

弹出框 II

leaflet() %>% 
     addTiles() %>% 
     addPopups(lng = dc_hq$lon, lat = dc_hq$lat,
               popup = dc_hq$hq)

弹出框示例

将 leaflet 地图存为对象

m <- leaflet() %>%
     addTiles()  %>% 
     setView(lng = dc_hq$lon[1], 
             lat = dc_hq$lat[1], 
             zoom = 12)

将地图存为对象

# %>% leaflet objects to functions 
# to add or edit layers
m %>% addMarkers(lng = dc_hq$lon, 
                 lat = dc_hq$lat, 
                 popup = dc_hq$hq)

向图层添加内容

开始练习！

在 R 中使用 leaflet 构建交互式地图