CODEWITHSUNDEEP
rshinyr-leaflet
heyydrien
heyydrien

Reputation: 981

Update datatable when zooming with leaflet

I am building a shiny application which contains a leaflet map with markers on it, and a table with information about each marker next to it. As I zoom in the leaflet map, how would I update the table to only show markers still visible on the leaflet map? 

# Minimum Viable Example


library(shiny)
library(leaflet)
library(DT)
data(quakes)

# Define UI
ui <- fluidPage(
    # leaflet box
    column(
        leafletOutput("mymap"),
        width = 8
    ),
    #data table box
    column(
        DT::dataTableOutput("table"),
        width = 4
    )
)

# Define server logic 
server <- function(input, output) {

    # leaflet map
    output$mymap <- renderLeaflet({
        # Show first 20 rows from the `quakes` dataset
        leaflet(data = quakes[1:20,]) %>% addTiles() %>%
            addMarkers(~long, ~lat, popup = ~as.character(mag), label = ~as.character(mag))
    })

    # data table
    output$table = DT::renderDataTable({
        quakes
    })

}

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

Upvotes: 1

Views: 641

Answers (1)

Kent Johnson
Kent Johnson

Reputation: 3388

Use the input$mymap_bounds event to filter the data. In your example, add library(dplyr) and change output$table to

    output$table = DT::renderDataTable({
      if (isTruthy(input$mymap_bounds)) {
        bounds = input$mymap_bounds
        quakes %>% filter(
          between(long, bounds$west, bounds$east),
          between(lat, bounds$south, bounds$north)
        )
      } else
        quakes
    })

Note that this filters the entire quakes table, not the 20 items you show. Modify to suit. See the Events section of this page for details: https://rstudio.github.io/leaflet/shiny.html

Upvotes: 1

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