如何使用传单 R 绘制基于国家/地区的等值线答案

【问题标题】：How to plot country-based choropleths using leaflet R如何使用传单 R 绘制基于国家/地区的等值线
【发布时间】：2020-03-10 05:24:41
【问题描述】：

世界边界geo.json从这里下载。https://github.com/johan/world.geo.json

我正在尝试突出显示 3 个国家/地区（在世界地图视图中）并根据该国家/地区的项目数量以渐变颜色绘制它们。

这是我的步骤：

首先下载世界边界geo.json文件并作为底图读取；然后我尝试在我的数据中突出显示国家多边形。然而事实证明，世界上所有的国家都被这三个国家的信息随机着色和标记。是地理数据框子集问题吗？

WorldCountry <-geojsonio::geojson_read("./GeoData/countries.geo.json", what = "sp")

#Dataframe for choropleth map
Country <- c("Bulgaria","Pakistan","Turkey")
Projects <- c(2,1,6)
data <- data.frame(Country,Projects)

#basemap
Map <- leaflet(WorldCountry) %>% addTiles() %>% addPolygons()

#set bin and color for choropleth map
bins <- c(0,1,2,3,4,5,6,7,8,9,10,Inf)
pal <- colorBin("YlOrRd", domain = data$Projects, bins = bins)

#set labels
labels <- sprintf(
  "<strong>%s</strong><br/>%g projects <sup></sup>",
  data$Country, data$Projects) %>% lapply(htmltools::HTML)

#add polygons,labels and mouse over effect
Map %>% addPolygons(
  fillColor = ~pal(data$Projects),
  weight = 2,
  opacity = 1,
  color = 'white',
  dashArray = '3',
  fillOpacity = 0.7,
  highlight = highlightOptions(
     weight = 5,
    color = "#666",
    dashArray = "",
    fillOpacity = 0.7,
    bringToFront = TRUE),
  label = labels,
  labelOptions = labelOptions(
    style = list("font-weight" = "normal", padding = "3px 8px"),
    textsize = "15px",
    direction = "auto")
)

我期待这样的事情：

【问题讨论】：

标签： json r leaflet geospatial

【解决方案1】：

这样就可以了！使用以下方法对 WorldCountry 进行子集：

data_Map <- WorldCountry[WorldCountry$id %in% data$Country, ]
Map <- leaflet(data_Map) %>% addTiles() %>% addPolygons()

【讨论】：

【解决方案2】：

子集将是 WorldCountry$name

data_Map <- WorldCountry[WorldCountry$name %in% data$Country, ]

Map <- leaflet(data_Map) %>% addTiles() %>% addPolygons(
  fillColor = ~pal(data$Projects),
  weight = 2,
  opacity = 1,
  color = 'white',
  dashArray = '3',
  fillOpacity = 0.7,
  highlight = highlightOptions(
    weight = 5,
    color = "#666",
    dashArray = "",
    fillOpacity = 0.7,
    bringToFront = TRUE),
  label = labels,
  labelOptions = labelOptions(
    style = list("font-weight" = "normal", padding = "3px 8px"),
    textsize = "15px",
    direction = "auto")
)

【讨论】：