Exporting selected map data in Shiny

[Zach]

I put together some code to display data points on a map and then added in the edit functionality. My question is: Is it be possible to then take the selected data and push it to a data frame on Shiny that say, could be downloaded by the end user in CSV? Below is a screenshot of what it looks like so far, so the idea would be to take all the data points selected and push it to a CSV within Shiny:

 library(mapedit)
  library(mapview)
  library(shiny)
  library(leaflet)
  library(leaflet.extras)
  library(sf)
  
  # select as a module
    m = leaflet(turf_clean_mapped) %>%
    addCircleMarkers(weight = 1, layerId = 1:nrow(turf_clean))
  
  ui <- tagList(
    selectModUI("test-mod"),
    DT::dataTableOutput("selected")
  )
  server <- function(input, output, session) {
    selections <- callModule(selectMod, "test-mod", m)
    output$selected <- DT::renderDataTable({DT::datatable(selections())})
    observe({str(selections())})
  }
  shinyApp(ui, server)
  
  # edit as a module
  
  m = mapview(turf_clean_mapped)@map
  testsf = NULL
  ui <- tagList(
    editModUI("test-edit"),
    h1("What You Draw"),
    leafletOutput("edited")
  )
  server <- function(input, output, session) {
    crud <- callModule(editMod, "test-edit", m, "turf_clean_mapped")
    output$edited <- renderLeaflet({
      req(crud()$finished)
      mapview(crud()$finished)@map
    })
  }
  shinyApp(ui, server)
  
  
  # editMap module can easily be combined to make a selection tool
  #   do selection of breweries with drawn polygons
  
  ui <- fluidPage(
    fluidRow(
      column(6,editModUI("brew-select")),
      column(6,leafletOutput("mapout"))
    )
  )
  server <- function(input,output,session) {
    m = mapview(turf_clean_mapped)@map
    turf_sf <- st_as_sf(turf_clean_mapped)
    drawn <- callModule(editMod, "brew-select", m)
    calc_sf <- reactiveValues()
    observe({
      req(drawn()$finished)
      calc_sf$intersection <- st_intersection(drawn()$finished, turf_sf)
    })
    output$mapout <- renderLeaflet({
      req(calc_sf$intersection)
      (mapview(calc_sf$intersection) + mapview(drawn()$finished))@map
    })
  }
  shinyApp(ui,server)

[tim-salabim]

selectFeatures will do what you want, but I am not sure how to use it in a shiny app.

[Jen Williams]

I do something similar to this in my app @za123 , and just use a standard shiny downloadhandler. How you implement that would depend on what columns/data you want in your CSV file.

In mine I have some underlying data, which is filtered by the drawn()$finished features collection; that filtered data is what I use in my downloadHandler / downloadButton

[Matthew English]

Hey @Za213

I also have some code to handle this kind of thing. In your ui you need to have uiOutput("download") somehwere in a fluidRow(). In your server, i do the following:

#this makes the download button appear only once data are selected
output$download <- renderUI({
    if(!is.null(calc_sf$intersection) {
      downloadButton("downloadData", "Download .csv")
    }
  })
  
  # Downloadable csv of selected dataset 
  output$downloadData <- downloadHandler(
    filename = function() { 
      paste("mydata", Sys.Date(),".csv", sep="") #this just pastes the date to the filename
    },
    content = function(file) {
      write.csv(calc_sf$intersection, file, row.names = FALSE)
    })

Best of luck~