SelectInput and Leaflet not connecting

Question

I am trying to use shinyApp with the leaflet package. I have tried using the "SelectInput" function in the dashboard to create a reactive map based on the input selected(country).However, I am not able to make the leaflet and the SelectInput connect with each other.

Here is my code:

library(shiny)
library(leaflet)

ui <- (fluidPage(
titlePanel(title = "Pig breeding countries in 2000 - Top 5"),
sidebarLayout(
sidebarPanel(
selectInput(inputId = "country",
label = "Select a country to view it's values       (you can choose more than one):",
 c("Brazil", "China", "Russia", "USA", "Vietnam"), multiple = TRUE
              )
  ),
#mainPanel must be outside the sidebarLayout argument
mainPanel(leafletOutput("mymap", height = "500"),
          leafletOutput("country")
))
)
)

server <- (function(input, output){
output$mymap <- renderLeaflet(input$country)
output$mymap <- renderLeaflet({
mymap = leaflet()
setView(mymap, lng = -16.882374406249937, lat = -1.7206857960062047, zoom = 0)
mymap = addProviderTiles(mymap, provider = "CartoDB.Positron")
mymap = addMarkers(mymap,lng = 101.901875, lat = 35.486703, popup = "China 35,500")
mymap = addMarkers(mymap,lng = -95.712891, lat = 37.090240, popup = "USA 6,267")
mymap = addMarkers(mymap,lng = 108.339537, lat = 14.315424, popup = "Vietnam 2,947")
mymap = addMarkers(mymap,lng = 37.618423, lat = 55.751244, popup = "Russia 3,070")
mymap = addMarkers(mymap,lng = -46.625290, lat = -23.533773, popup = "Brazil 3,020")}
})
shinyApp(ui, server)

Can someone advise how to link them?

score 1 · Accepted Answer · answered Feb 20 '19 at 09:34

There is no reactive environment between your drop-down selection and leaflet map in your code. Check in the below code to create reactive leaflet map.

library(shiny)
library(leaflet)
df <- read.csv("leaflet.csv")
ui <- (fluidPage(
  titlePanel(title = "Pig breeding countries in 2000 - Top 5"),
  sidebarLayout(
    sidebarPanel( uiOutput("countrynames")
    ),
    mainPanel(leafletOutput("mymap", height = "500")
    ))
)
)

server <- function(input, output){
  output$countrynames <- renderUI({
  selectInput(inputId = "country", label = "Select a country to view it's values (you can choose more than one):",
              c(as.character(df$country)))
  })
  map_data <- reactive({
    data <- data.frame(df[df$country == input$country,])
    data$popup <- paste0(data$country, " ", data$number)
    return(data)
  })
  output$mymap <- renderLeaflet({
    leaflet(data = map_data()) %>%
      # setView( lng = -16.882374406249937, lat = -1.7206857960062047, zoom = 0) %>%
      addProviderTiles( provider = "CartoDB.Positron") %>%
      addMarkers(lng = ~lng, lat = ~lat, popup = ~popup)
      # addCircles(lng = ~lng, lat = ~lat, popup = ~popup)
  })
  }
  shinyApp(ui, server)

Below is the csv file i have imported in code.

structure(list(lng = c(101.901875, -95.712891, 108.339537, 37.618423
), lat = c(35.486703, 37.09024, 14.315424, 55.751244), country = structure(c(1L, 
3L, 4L, 2L), .Label = c("China", "Russia", "USA", "Vietnam"), class = "factor"), 
    number = c(35500L, 6267L, 2947L, 3070L)), .Names = c("lng", 
"lat", "country", "number"), class = "data.frame", row.names = c(NA, 
-4L))

Thank you sooo much for this! I have been scratching my brain for hours! — Rooty1985, Feb 20 '19 at 12:19
I am now getting an error when trying to run the code: object of type 'closure' is not subsettable - is this to do with the data frame? — Rooty1985, Feb 20 '19 at 12:37
Have you tried any modifications in the code? If so, can you post the modification details? — msr_003, Feb 20 '19 at 17:28
Please ignore my last comment...sorry!!! my silly error I thought the csv file was in the same folder as my app.R file clearly not as I got the error. Thank you for sorting this for me looks much much better than anything I could have created... thanks again :) — Rooty1985, Feb 21 '19 at 08:54

SelectInput and Leaflet not connecting

1 Answers1