在 Shiny 中应用传单地图边界来过滤数据

Question

下面的代码旨在重现 this example 中的内容，但为 "speed" 添加了一个附加参数。但是，我的地图数据table link 坏了 - 谁能帮我找出错误？原始代码根据地图的边界更新 table，而在我的代码中更改地图缩放对我的 table 没有影响。我也无法让 "speed" 过滤器在 table 和地图上工作，这是我正在寻找的功能。任何指针将不胜感激。

library(shiny)
library(magrittr)
library(leaflet)
library(DT)

ships <-
  read.csv(
    "https://raw.githubusercontent.com/Appsilon/crossfilter-demo/master/app/ships.csv"
  )

ui <- shinyUI(fluidPage(
  titlePanel(""),
  sidebarLayout(
    sidebarPanel(width = 3,
                 numericInput(
                   "speed", label = h5("Ship's Speed"), value = 100
                 )),
    mainPanel(tabsetPanel(
      type = "tabs",
      tabPanel(
        "Leaflet",
        leafletOutput("leafletmap", width = "350px"),
        dataTableOutput("tbl")
      )
    ))
  )
))

server <- shinyServer(function(input, output) {
  in_bounding_box <- function(data, lat, long, bounds, speed) {
    data %>%
      dplyr::filter(
        lat > bounds$south &
          lat < bounds$north &
          long < bounds$east & long > bounds$west & ship_speed < input$speed
      )
  }

  output$leafletmap <- renderLeaflet({
    leaflet() %>%
      addProviderTiles("Esri.WorldImagery", group = "ESRI World Imagery") %>%
      addCircleMarkers(
        data = ships,
        ~ long ,
        ~ lat,
        popup =  ~ speed,
        radius = 5 ,
        stroke = FALSE,
        fillOpacity = 0.8,
        popupOptions = popupOptions(closeButton = FALSE)
      )
  })

  data_map <- reactive({
    if (is.null(input$map_bounds)) {
      ships
    } else {
      bounds <- input$map_bounds
      in_bounding_box(ships, lat, long, bounds, speed)
    }
  })

  output$tbl <- DT::renderDataTable({
    DT::datatable(
      data_map(),
      extensions = "Scroller",
      style = "bootstrap",
      class = "compact",
      width = "100%",
      options = list(
        deferRender = TRUE,
        scrollY = 300,
        scroller = TRUE,
        dom = 'tp'
      )
    )
  })


})

shinyApp(ui = ui, server = server)

Answer 1

您正在渲染的传单地图名为leafletmap。因此，与其引用 map_bounds，不如尝试将其更改为 leafletmap_bounds:

  data_map <- reactive({
    if (is.null(input$leafletmap_bounds)) {
      ships
    } else {
      bounds <- input$leafletmap_bounds
      in_bounding_box(ships, lat, long, bounds, speed)
    }
  })

同样在过滤器中，将 ship_speed 更改为 speed。应该有希望工作。

Answer 2

两个小变化：

在您链接的示例中，input$map_bounds 有效，因为传单输出对象称为 map。但是，您将其重命名为leafletmap，因此我们应该参考input$leafletmap_bounds。
在dplyr语句中，我们应该引用speed，而不是ship_speed。

下面给出了工作代码，希望对您有所帮助！

library(shiny)
library(magrittr)
library(leaflet)
library(DT)

ships <-
  read.csv(
    "https://raw.githubusercontent.com/Appsilon/crossfilter-demo/master/app/ships.csv"
  )

ui <- shinyUI(fluidPage(
  titlePanel(""),
  sidebarLayout(
    sidebarPanel(width = 3,
                 numericInput(
                   "speed", label = h5("Ship's Speed"), value = 100
                 )),
    mainPanel(tabsetPanel(
      type = "tabs",
      tabPanel(
        "Leaflet",
        leafletOutput("leafletmap", width = "350px"),
        dataTableOutput("tbl")
      )
    ))
  )
))

server <- shinyServer(function(input, output) {
  in_bounding_box <- function(data, lat, long, bounds, speed) {
    data %>%
      dplyr::filter(
        lat > bounds$south &
          lat < bounds$north &
          long < bounds$east & long > bounds$west & speed < input$speed
      )
  }

  output$leafletmap <- renderLeaflet({
    leaflet() %>%
      addProviderTiles("Esri.WorldImagery", group = "ESRI World Imagery") %>%
      addCircleMarkers(
        data = ships,
        ~ long ,
        ~ lat,
        popup =  ~ speed,
        radius = 5 ,
        stroke = FALSE,
        fillOpacity = 0.8,
        popupOptions = popupOptions(closeButton = FALSE)
      )
  })

  data_map <- reactive({
    if (is.null(input$leafletmap_bounds)) {
      ships
    } else {
      bounds <- input$leafletmap_bounds
      in_bounding_box(ships, lat, long, bounds, speed)
    }
  })

  output$tbl <- DT::renderDataTable({
    DT::datatable(
      data_map(),
      extensions = "Scroller",
      style = "bootstrap",
      class = "compact",
      width = "100%",
      options = list(
        deferRender = TRUE,
        scrollY = 300,
        scroller = TRUE,
        dom = 'tp'
      )
    )
  })


})

shinyApp(ui = ui, server = server)

在 Shiny 中应用传单地图边界来过滤数据

Applying leaflet map bounds to filter data, within Shiny

r

shiny

leaflet

reactive-programming

r-leaflet