如何在数据集中创建没有纬度和经度的 R shiny 交互式 map

Question

using leaflet package to create interactive map using r shiny. 我的数据集提供了国家的名称，但没有提供经纬度。 我如何在 map 可以通过国家名称检测的地方创建这个

Answer 1

您可以使用 geojson map 和readOGR function，您可以在 Internet 上找到 map 并将您的数据集链接到它。

rgdal::readOGR(dsn = "GeoJSON map", 
                     layer = "OGRGeoJSON", 
                     stringsAsFactors = FALSE)

以下是基于此stackoverflow 帖子的示例，用于在 R Shiny 上制作交互式 map。 所选国家/地区位于click.list$ids中，请参见下面的output$selected_var 。

您的数据

## packages ##

packages <- c("leaflet", "shiny", "shinydashboard")

newPackages <- packages[!(packages %in% installed.packages()[,"Package"])]
if(length(newPackages)) install.packages(newPackages)
lapply(packages, library, character.only = TRUE)
remove(packages, newPackages)

## map & data ##

Europe <- rgdal::readOGR(dsn = "https://data.opendatasoft.com/explore/dataset/european-union-countries@public/download/?format=geojson&timezone=Europe/Berlin", 
                         layer = "OGRGeoJSON", 
                         stringsAsFactors = FALSE)

data <- data.frame("name" = c("Austria", "Belgium", "Bulgaria", "Croatia", "Cyprus", "Czechia", "Denmark", "Estonia",
                              "Finland", "France", "Germany", "Greece", "Hungary", "Iceland", "Ireland", "Italy", "Latvia",
                              "Liechtenstein", "Lithuania", "Luxembourg", "Malta", "Netherlands", "Norway", "Poland", "Portugal",
                              "Romania", "Slovakia", "Slovenia", "Spain", "Sweden", "Switzerland", "Turkey", "United Kingdom"),
                   "polcapita" = c(0.0087928207, 0.0100464969, 0.0075375536, 0.0049040898, 0.0097860082, 0.0119440135, 0.0087740252, 
                                   0.0080851042, 0.0063462331, 0.0064707328, 0.0107846429, 0.0085740997, 0.0059612600, 0.0409884683, 
                                   0.0138830047, 0.0067616652, 0.0049423915, 0.0053782730, 0.0053461017, 0.0165884166, 0.0046052235, 
                                   0.0116079951, 0.0052533159, 0.0100049243, 0.0075509189, 0.0047028415, 0.0067531703, 0.0077087169, 
                                   0.0064795469, 0.0008881585, 0.0053907055, 0.0053085690, 0.0069728195))

# example if you need to change the name of a country
Europe@data[Europe@data$name == "Czech Rep.", ]$name <- "Czechia"

# example if you want to add datas to the map
Europe@data$polcapita <- merge(x = Europe@data, y = data, sort = FALSE)$polcapita

pal <- colorNumeric(c("Green", "Red"), Europe$polcapita)

界面部分

## create the UI ##

ui <- fluidPage(
  # place the contents inside a box
  shinydashboard::box(
    width = 12, 
    title = "Click on the map!",
    # separate the box by a column
    column(width = 2,
           shiny::actionButton(inputId = "clearHighlight",
                               icon = icon( name = "eraser"),
                               label = "Clear the Map",
                               style = "color: #fff; background-color: #D75453; border-color: #C73232")),
    # separate the box by a column
    column(width = 10, 
           leaflet::leafletOutput(outputId = "myMap", height = 850)),
    column(width = 5,
           textOutput("selected_var"))
  )
)

服务器部分

## create the server ##

server <- function( input, output, session ){

  # create foundational map
  foundational.map <- shiny::reactive({
    leaflet(Europe) %>% 
      fitBounds(-20, 65, 20, 39) %>% 
      addProviderTiles(providers$CartoDB.Positron) %>% 
      addPolygons(data = Europe, 
                  layerId = Europe$name, 
                  color = ~pal(polcapita), 
                  group = "click.list",
                  weight = 2, 
                  fillOpacity = 0.3, 
                  opacity = 1,
                  smoothFactor = 0.2,
                  stroke = FALSE)
  })

  output$myMap <- renderLeaflet({
    foundational.map()
  }) 

  # store the list of clicked polygons in a vector
  click.list <- shiny::reactiveValues(ids = vector())

  # add countries to selection
  shiny::observeEvent(input$myMap_shape_click, {

    click <- input$myMap_shape_click
    if(click$id %in% click.list$ids){
      click.list$ids <- click.list$ids[!click.list$ids%in%click$id]
      leaflet::leafletProxy(mapId = "myMap") %>%
        clearGroup("lin")
    } else{
      click.list$ids <- c(click.list$ids, click$id)
    }
    lines.of.interest <- Europe[ which(Europe$name %in% click.list$ids), ]
    leaflet::leafletProxy(mapId = "myMap") %>%
      addPolylines(data = lines.of.interest, 
                   layerId = lines.of.interest$ids, 
                   color = "#6cb5bc", 
                   weight = 2, 
                   opacity = 1,
                   group = "lin")
  }) 

  # Clear the map button
  shiny::observeEvent( input$clearHighlight, { 
    output$myMap <- leaflet::renderLeaflet({
      click.list$ids <- NULL
      foundational.map()
    }) 
  }) 

  # selected countries
  output$selected_var <- renderText({ 
    paste("You have selected", click.list$ids)
  })

}

运行服务器

## run shinyApp ##
shiny::shinyApp(ui, server)

我希望它能回答你的问题！