Question

基于下面的评论，我明确在空间数据框中细分了经/纬度。

已添加

addCircleMarkers( ~ longitude, ~ latitude)

已添加

observeEvent(input$map_marker_click, { 
    p <- input$map_marker_click
    print(p)
  })

但是，当我单击标记时，控制台中什么都没有显示，所以我仍然感到困惑。

修改后的代码

# Click on circle and get info

library(shiny)
library(leaflet)

ui <- fluidPage(
  leafletOutput("mymap"),
  fluidRow(verbatimTextOutput("click_text"))
)

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

  # Create tree geometries
  tree_1g <- st_point(c(-79.2918671415814, 43.6760766531298))
  tree_2g <- st_point(c(-79.4883669334101, 43.6653747165064))
  tree_3g <- st_point(c(-79.2964680812039, 43.7134458013647))

  # Create sfc object with multiple sfg objects
  points_sfc <- st_sfc(tree_1g, tree_2g, tree_3g, crs = 4326)

  # Create tree attributes
  data <- data.frame (
    layerId = c("001", "002", "003"),
    address = c(10, 20, 30),
    street = c("first", "second", "third"),
    tname = c("oak", "elm", "birch"),
    latitude = c(43.6760766531298, 43.6653747165064, 43.7134458013647),
    longitude = c(-79.2918671415814, -79.4883669334101, -79.2964680812039)  
)

  tree_data <- st_sf(data, geometry = points_sfc)

  output$mymap <- renderLeaflet({
    leaflet(data = tree_data) %>%
      addProviderTiles(providers$Stamen.Watercolor) %>%

      # Centre the map in the middle of Toronto
      setView(lng = -79.384293, 
              lat = 43.685, 
              zoom = 11) %>% 

      addCircleMarkers( ~ longitude, ~ latitude)
  })

  observeEvent(input$map_marker_click, { 
    p <- input$map_marker_click
    print(p)
  })


}

shinyApp(ui, server)

当用户单击每个标记时，我希望在地图下方显示一些相关信息。基于此较早的post，我尝试了此操作。但是，当我单击标记时，什么也没有发生。可能与我不了解如何将标记与layerId相关联有关。

# Click on circle and get info

library(shiny)
library(leaflet)

ui <- fluidPage(
  leafletOutput("mymap"),
  fluidRow(verbatimTextOutput("click_text"))
)

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

  # Create tree geometries
  tree_1g <- st_point(c(-79.2918671415814, 43.6760766531298))
  tree_2g <- st_point(c(-79.4883669334101, 43.6653747165064))
  tree_3g <- st_point(c(-79.2964680812039, 43.7134458013647))

  # Create sfc object with multiple sfg objects
  points_sfc <- st_sfc(tree_1g, tree_2g, tree_3g, crs = 4326)

  # Create tree attributes
  data <- data.frame (
    layerId = c("001", "002", "003"),
    address = c(10, 20, 30),
    street = c("first", "second", "third"),
    tname = c("oak", "elm", "birch")
)

  tree_data <- st_sf(data, geometry = points_sfc)

  output$mymap <- renderLeaflet({
    leaflet(data = tree_data) %>%
      addProviderTiles(providers$Stamen.Watercolor) %>%

      # Centre the map in the middle of Toronto
      setView(lng = -79.384293, 
              lat = 43.685, 
              zoom = 11) %>% 

      addCircleMarkers()
  })

  observe({
    click <- input$map_marker_click
    if(is.null(click))
      return()

    address <- paste("Address: ", click$street)
    output$click_text <- renderText({
      address
    })

  })

}

shinyApp(ui, server)

Answer 1

当您“观察”地图上的某物时，您需要参考正在观察的地图。您可以使用此结构

output$<map_id>_event_to_observe

因此，在您的示例中，您的map_id是mymap，因此您需要使用

observeEvent(input$mymap_marker_click, { 
    p <- input$mymap_marker_click
    print(p)
  })

点击传单标记并获取信息

1 个答案: