Changing Leaflet map according to input without redrawing (multiple polygons)

Question

cannot fix my problem for MULTIPLE filters/polygons. Currently my code works, but very slow, I do not use observe(), reactive(), and LeafletProxy(), because I stumbled.

I obviously checked this answer Changing Leaflet map according to input without redrawing and this one Making Shiny UI Adjustments Without Redrawing Leaflet Maps and leaflet tutorial Using Leaflet with Shiny

In my case I have four filters and do not quite understand how to combine them together and make the map fast.

My sample data:

Country Client  Channel Status
Country 1   Client 1    Agent network   Launched
Country 2   Client 2    Debit cards Launched
Country 3   Client 3    M-banking   Planning
Country 4   Client 4    M-banking   Launched
Country 5   Client 5    Agent network   Launched
Country 6   Client 6    Agent network   Launched
Country 7   Client 7    Agent network   Pilot

This code works

# Packages
library(shiny)
library(shinythemes)
library(leaflet)
library(rgdal)

# Set working directory
setwd("C: /My Shiny apps")

# Read csv, which was created specifically for this app
projects <- read.csv("sample data10.csv", header = TRUE) 

# Read a shapefile
countries <- readOGR(".","ne_50m_admin_0_countries")

# Merge data
projects.df <- merge(countries, projects, by.x = "name", by.y = "Country")
class(projects.df)


# Shiny code

# UI

ui <- fluidPage(theme = shinytheme("united"),
            titlePanel("Map sample)"), 
            sidebarLayout(
              sidebarPanel(
                selectInput("countryInput", "Country",
                            choices = c("Choose country", "Country 1",
                                        "Country 2",
                                        "Country 3",
                                        "Country 4",
                                        "Country 5",
                                        "Country 6", 
                                        "Country 7"),
                            selected = "Choose country"),
                selectInput("clientInput", " Client",
                            choices = c("Choose Client", "Client 1",
                                        "Client 2",
                                        "Client 3",
                                        "Client 4",
                                        "Client 5",
                                        "Client 6"),
                            selected = "Choose Client"),
                selectInput("channeInput", "Channel",
                            choices = c("Choose Channel", "Agent network", 
"M-banking", "Debit cards"),
                            selected = "Choose Channel"),
                selectInput("statusInput", "Status",
                            choices = c("Choose status", "Launched", 
"Pilot", "Planning"),
                            selected = "Choose status")
              ),

              mainPanel(leafletOutput(outputId = 'map', height = 800) 
              )
            )
)

server <- function(input, output) {

output$map <- renderLeaflet({

pal1 <- colorFactor(
  palette = "Red",
  domain = input$countryInput)

pal2 <- colorFactor(
  palette = "Yellow",
  domain = input$clientInput)

pal3 <- colorFactor(
  palette = "Green",
  domain = input$channelInput)

pal4 <- colorFactor(
  palette = "Blue",
  domain = input$statusInput)

# Create a pop-up
state_popup <- paste0("Country: ", 
                      projects.df$name, 
                      "
 Client: ", 
                      projects.df$ Client,
                      "
 Channel: ", 
                      projects.df$Channel
                      "
Status: ", 
                      projects.df$Status)

# Create a map

projects.map <- projects.df %>%
  leaflet() %>%
  addTiles("Stamen.Watercolor") %>% 
  setView(11.0670977,0.912484, zoom = 4) %>% 
  addPolygons(fillColor = ~pal1(projects.df$name), 
              popup = state_popup,
              color = "#BDBDC3",
              fillOpacity = 1,
              weight = 1) %>%
  addPolygons(fillColor = ~pal2(projects.df$Client), 
              popup = state_popup,
              color = "#BDBDC3",
              opacity = 1,
              weight = 1) %>%
  addPolygons(fillColor = ~pal3(projects.df$Channel), 
              popup = state_popup,
              color = "#BDBDC3",
              opacity = 1,
              weight = 1) %>%
  addPolygons(fillColor = ~pal4(projects.df$Status), 
              popup = state_popup,
              color = "#BDBDC3",
              opacity = 1,
              weight = 1)
})

}

shinyApp(ui = ui, server = server)

Please help me to fix it with observe, reactive, and LeafletProxy and without redrawing map every time.

For me having these multiple filters/polygons make the situation really difficult.

Many thanks!

user_3048453 · Answer

Following this issue you can also create the map once and then recolor the polygons as you like.

This involves some javascript code, including the leafletjs code and then using the setShapeStyle function. Note that both the javascript and the setShapeStyle function are shown in the issue above.

# in ui
ui <- fluidPage(leafletjs, ...)

# in server
observe({
  leafletProxy("map") %>%
    setShapeStyle(layerId = ~LayerIDs, fillColor=input$color)
})

Changing Leaflet map according to input without redrawing (multiple polygons)

3 Answers