R - Shiny - Duplicate markers on map with leaflet

Question

I have a map in my shiny App.

I try to filters the markers on my map by a column of my dataframe.

My Data :

remorque       time.stamp      lat      long geolocalisation maintenance temperature appairage
1        21/11/2017 10:36 48.86272 2.2875920          OnMouv        noir                      
2        21/11/2017 10:36 43.60776 1.4421606       StartMouv                   rouge          
3        21/11/2017 10:36 46.58619 0.3388710          OnMouv                   rouge          
4        21/11/2017 10:36 45.76695 3.0556216            Life                  orange          
5        21/11/2017 10:36 45.14555 1.4751652         EndMouv                             rouge
6        21/11/2017 10:36 46.81157 1.6936336            Life                  orange          
7        21/11/2017 10:36 47.36223 0.6751146          alerte                             rouge
8        21/11/2017 10:36 47.36032 1.7441244       StartMouv                                  
9        21/11/2017 10:36 48.85333 1.8215332       StartMouv                                  
10       21/11/2017 10:36 48.84429 1.7913208          alerte                                  
11       21/11/2017 10:36 48.81356 1.6759643         EndMouv

In ui.R I add :

selectInput("geolocalisation", "Géolocalisation :",
                          choice = list("Tous" = "tous",
                                        "OnMouv" = "OnMouv",
                                        "StartMouv" = "StartMouv",
                                        "EndMouv" = "EndMouv",
                                        "Life" = "Life",
                                        "Perte ou Vol" = "alerte"))

And in server.R I did :

output$map <- renderLeaflet({
# Use leaflet() here, and only include aspects of the map that
# won't need to change dynamically (at least, not unless the
# entire map is being torn down and recreated).
leaflet() %>% 
  addTiles() 
})

zerg <-reactive({
test<-ifelse(input$geolocalisation=="OnMouv", return(data_moment[data_moment$geolocalisation=="OnMouv",]),
             ifelse(input$geolocalisation=="StartMouv", return(data_moment[data_moment$geolocalisation=="StartMouv",]),
                    ifelse(input$geolocalisation=="EndMouv", return(data_moment[data_moment$geolocalisation=="EndMouv",]),
                           ifelse(input$geolocalisation=="Life", return(data_moment[data_moment$geolocalisation=="Life",]),
                                  ifelse(input$geolocalisation=="alerte", return(data_moment[data_moment$geolocalisation=="alerte",]),
                                         return(data_moment))))))
return(test)
})


observe({

dataset<- zerg()

leafletProxy("map", data = dataset) %>%
  clearMarkers() %>%
  addMarkers(~long, ~lat,clusterOptions = markerClusterOptions(), icon = load_icons(dataset),
             popup= ~paste("<h4><font color='#2B547E'><b>Remorque : </font></b>",remorque,"</h4><h4><font color='#2B547E'>Latitude : </font>",lat,"</h4><h4><font color='#2B547E'>Longitude : </font>",long,"</h4>"),
             label = ~paste("Remorque : ",remorque,"::: Latitude : ",lat,"::: Longitude : ",long))

})

When I lauch the app, All the markers are displayed (that's good). And when I make a selection, it adds markers, not selecting markers. Just adding new ones which are duplicates.

Do you know why ?

since you are using leafletProxy the map is being updated each time with addMarkers, thus new markers on top of old. If you want to strip off the old markers each time the data is updated, just add a removeMarkers call before you call addMarkers — Nate
When I add removeMarker I get : Error in evalAll: argument "layerId" is missing, with no default. I think I am not adding it at the right place. — celianou
your right it should be removing the markers whoops I missed that, It's hard to help figure out specifics without a reproducible example — Nate
I saw things on the internet like observeEvent should be used. But it didn't work. Error in eval: argument "expr" is missing, with no default — celianou

Nate Nate · Accepted Answer · 2017-11-22T14:53:28

So the secret sauce was to use clearClusterMarkers() instead of clearMarkers() since you adjust the markers to cluster markers when you define the argument clusterOptions = markerClusterOptions.

Here is the long form of a working single file app.R

library(shiny)
library(leaflet)

data_moment <- read.table(
text =
"remorque       time.stamp      lat      long geolocalisation
1        21/11/2017 10:36 48.86272 2.2875920          OnMouv 
2        21/11/2017 10:36 43.60776 1.4421606       StartMouv 
3        21/11/2017 10:36 46.58619 0.3388710          OnMouv
4        21/11/2017 10:36 45.76695 3.0556216            Life
5        21/11/2017 10:36 45.14555 1.4751652         EndMouv
6        21/11/2017 10:36 46.81157 1.6936336            Life
7        21/11/2017 10:36 47.36223 0.6751146          alerte
8        21/11/2017 10:36 47.36032 1.7441244       StartMouv                                  
9        21/11/2017 10:36 48.85333 1.8215332       StartMouv                                  
10       21/11/2017 10:36 48.84429 1.7913208          alerte                                  
11       21/11/2017 10:36 48.81356 1.6759643         EndMouv", header = TRUE)

ui <- fluidPage(

   titlePanel("A map"),

   sidebarLayout(
      sidebarPanel(
          selectInput("geolocalisation", "Géolocalisation :",
                      choice = list("Tous" = "tous",
                                    "OnMouv" = "OnMouv",
                                    "StartMouv" = "StartMouv",
                                    "EndMouv" = "EndMouv",
                                    "Life" = "Life",
                                    "Perte ou Vol" = "alerte"))
      ),

      mainPanel(
         leafletOutput("map")
      )
   )
)

server <- function(input, output) {
    output$map <- renderLeaflet({
        # Use leaflet() here, and only include aspects of the map that
        # won't need to change dynamically (at least, not unless the
        # entire map is being torn down and recreated).
        leaflet() %>% 
            addTiles() %>%
            # I added this so we don't have to zoom in from outer space each time
            setView(lng = 2.3522, lat = 48.8566, zoom = 5)
    })

    zerg <-reactive({
        test<-ifelse(input$geolocalisation=="OnMouv", return(data_moment[data_moment$geolocalisation=="OnMouv",]),
                     ifelse(input$geolocalisation=="StartMouv", return(data_moment[data_moment$geolocalisation=="StartMouv",]),
                            ifelse(input$geolocalisation=="EndMouv", return(data_moment[data_moment$geolocalisation=="EndMouv",]),
                                   ifelse(input$geolocalisation=="Life", return(data_moment[data_moment$geolocalisation=="Life",]),
                                          ifelse(input$geolocalisation=="alerte", return(data_moment[data_moment$geolocalisation=="alerte",]),
                                                 return(data_moment))))))
        return(test)
    })


    observe({

        data_set <- zerg

        leafletProxy("map", data = zerg()) %>%
            # this is the only change you really need
            clearMarkerClusters() %>%
            addMarkers(~long, ~lat, clusterOptions = markerClusterOptions(),
                       popup= ~paste("<h4><font color='#2B547E'><b>Remorque : </font></b>",remorque,"</h4><h4><font color='#2B547E'>Latitude : </font>",lat,"</h4><h4><font color='#2B547E'>Longitude : </font>",long,"</h4>"),
                       label = ~paste("Remorque : ",remorque,"::: Latitude : ",lat,"::: Longitude : ",long))

    })
}

shinyApp(ui = ui, server = server)

R - Shiny - Duplicate markers on map with leaflet

1 Answers