将反应性弹出图/绘图添加到 Leaflet map 与 Shiny ZE1E1D3D40573127E9ZEE08

Question

I have built a Shiny dashboard. The user can select a municipality from a dropdown menu, after which a range of data from that municipality are downloaded and visualized with Leaflet. A main user requirement is that clicking an area on the map generates a popup graph with all the scores for that area (see image below)

This was my general approach:

1. Store the name of the area that the user clicked as a reactive value
2. Use the reactive value in a function that generates a ggplot graph
3. Add the ggplot graph to a popup with the addPopupGraphs function from the leafpop package

This shouldn't be so hard, but I have been stuck for days. I have also attempted to generate a list of graphs (one for each area in the municipality), since I believe that is how leafpop works. However, once again to success. Does anyone have a solution to my struggle?

Reproducable example:

library(sf)
library(dplyr)
library(shiny)
library(shinydashboard)
library(leaflet)
library(leafpop)
library(ggplot2)
library(reshape2)

# Let's use this municipality in the example
inputMunicipality = "Landgraaf"

# Download municipality geometry
df <-st_read(URLencode(sprintf("https://geo.leefbaarometer.nl/leefbaarometer/wfs?version=1.0.0&cql_filter=gemeente=%s%s%s&request=GetFeature&typeName=leefbaarometer:wijken_2018&srsName=epsg:4326&outputFormat=json",
                                               "'", inputMunicipality, "'")))[c("WK_NAAM", "WK_CODE")]
# Add some fake scores
df$environmentScore <- sample(10, size = nrow(df), replace = TRUE)
df$facilitiesScore <- sample(10, size = nrow(df), replace = TRUE)
df$housingScore <- sample(10, size = nrow(df), replace = TRUE)
df$safetyScore <- sample(10, size = nrow(df), replace = TRUE)


# Define dashboard UI 
ui <- dashboardPage(
  dashboardHeader(title = "Testing reactive popup on click event!"),
  dashboardSidebar(),
  dashboardBody(
    fluidRow(leafletOutput("myMap")
             )
    )
  )


# Define server logic 
server <- function(input, output) {
  
  # When a person clicks the map, the name of the clicked area is saved in this reactive value
  clickValue <- reactiveValues(areaName=NULL)
  # I then want to use the reactive "clickValue$areaName" in this function to generate a reactive ggplot
  # The reactive ggplot should then be shown as a popup with the addPopupGraphs function
  reactivePopup <- reactive ({
    makePopupPlot(clickValue$areaName, df)
    })
  
  output$myMap <- renderLeaflet({
    leaflet() %>% 
      addProviderTiles(providers$nlmaps.grijs) %>%
      addPolygons(data = df, weight = 1, fillOpacity = 0.3,
                  group = "test", layerId = ~WK_CODE, popup = df$WK_NAAM) %>%
      addPopupGraphs(list(nonReactiveExamplePopup), group = "test", width = 500, height = 200) 
  })
  
  
  # Save the name of a clicked area in a reactive variable
  observeEvent(input$map_shape_click, { 
    event <- input$map_shape_click
    clickAreaName <- df$WK_NAAM[df$WK_CODE == event$id]
    clickValue$areaName <- clickAreaName

  })
}

  
# Run the application 
shinyApp(ui = ui, server = server)


# Function for generation a popup based on the area clicked by the user
makePopupPlot <- function (clickedArea, df) {
  # prepare the df for ggplot
  noGeom <- st_drop_geometry(df)
  plotData <- noGeom[c("WK_NAAM", "environmentScore", "facilitiesScore","housingScore", "safetyScore")]
  plotDataSubset <- subset(plotData, plotData['WK_NAAM'] == clickedArea) 
  plotDataMelt = melt(plotDataSubset, id.vars = "WK_NAAM")
  
  popupPlot <- ggplot(data = plotDataMelt,  aes(x = variable, y = value, fill=value)) + 
    geom_bar(position="stack", stat="identity", width = 0.9) +
    scale_fill_steps2(
      low = "#ff0000",
      mid = "#fff2cc",
      high = "#70ad47",
      midpoint = 5) +
    coord_flip() +
    ggtitle(paste0("Score overview in ", clickedArea)) + 
    theme(legend.position = "none")

  return (popupPlot)
}

# Add this graph to addPopupGraphs(list() to see how I want it to work
nonReactiveExamplePopup <- makePopupPlot("Wijk 00 Schaesberg", df)

Answer 1

If I understood correctly:

library(sf)
library(dplyr)
library(shiny)
library(shinydashboard)
library(leaflet)
library(leafpop)
library(ggplot2)
library(reshape2)


set.seed(1)

# Let's use this municipality in the example
inputMunicipality = "Landgraaf"

# Download municipality geometry
df <-st_read(URLencode(sprintf("https://geo.leefbaarometer.nl/leefbaarometer/wfs?version=1.0.0&cql_filter=gemeente=%s%s%s&request=GetFeature&typeName=leefbaarometer:wijken_2018&srsName=epsg:4326&outputFormat=json",
                               "'", inputMunicipality, "'")))[c("WK_NAAM", "WK_CODE")]
# Add some fake scores
df$environmentScore <- sample(10, size = nrow(df), replace = TRUE)
df$facilitiesScore <- sample(10, size = nrow(df), replace = TRUE)
df$housingScore <- sample(10, size = nrow(df), replace = TRUE)
df$safetyScore <- sample(10, size = nrow(df), replace = TRUE)


# Define dashboard UI 
ui <- dashboardPage(
  dashboardHeader(title = "Testing reactive popup on click event!"),
  dashboardSidebar(),
  dashboardBody(
    fluidRow(leafletOutput("myMap")
    )
  )
)


# Define server logic 
server <- function(input, output) {
  
  # Function for generation a popup based on the area clicked by the user
  makePopupPlot <- function (clickedArea, df) {
    # prepare the df for ggplot
    noGeom <- st_drop_geometry(df)
    plotData <- noGeom[c("WK_NAAM", "environmentScore", "facilitiesScore","housingScore", "safetyScore")]
    plotDataSubset <- subset(plotData, plotData['WK_NAAM'] == clickedArea) 
    plotDataMelt = melt(plotDataSubset, id.vars = "WK_NAAM")
    
    popupPlot <- ggplot(data = plotDataMelt,  aes(x = variable, y = value, fill=value)) + 
      geom_bar(position="stack", stat="identity", width = 0.9) +
      scale_fill_steps2(
        low = "#ff0000",
        mid = "#fff2cc",
        high = "#70ad47",
        midpoint = 5) +
      coord_flip() +
      ggtitle(paste0("Score overview in ", clickedArea)) + 
      theme(legend.position = "none") +
      theme(plot.margin = unit(c(0,0.5,0,0), "cm"), plot.title = element_text(size = 10))
    
    return (popupPlot)
  }
  
  # chart list
  p <- as.list(NULL)
  p <- lapply(1:nrow(df), function(i) {
    p[[i]] <- makePopupPlot(df$WK_NAAM[i], df)
  })
  
  output$myMap <- renderLeaflet({
    leaflet() %>% 
      addProviderTiles(providers$nlmaps.grijs) %>%
      addPolygons(data = df, popup = popupGraph(p, type = "svg")) 
  })
}


# Run the application 
shinyApp(ui = ui, server = server)