Linked brushing with plotly & leaflet

README.md

Shiny app to highlight on a Leaflet map by brushing a Plotly chart. Run for yourself with (provided all of the packages are installed):

shiny::runGist('da941dac84f730adcdde')

To get this to work on another dataset, you're going to need to have a sequential ID variable that matches the pointNumber column in the data frame generated by Plotly's event_data. See the setup.R script for how this was derived.

app.R

library(shiny)
library(leaflet)
library(plotly)
library(rgdal)
# devtools::install_github("ropensci/geojsonio")
library(geojsonio)
# devtools::install_github("ateucher/rmapshaper")
library(rmapshaper)

#tarr <- readOGR(dsn = '.', layer = 'tarrant_precincts')
#tarr_simp <- ms_simplify(tarr)
#tarrxy <- spTransform(tarr_simp, CRS("+proj=longlat +datum=WGS84"))
#tarrxy <- tarrxy[tarrxy$pctrep != -1 & tarrxy$pctwhite != -1, ]
#l1 <- length(tarrxy) - 1
#tarrxy$id <- 0:l1
#geojson_write(tarrxy, file = 'tarrxy.geojson')

if (!file.exists('tarrxy.geojson')) {
  download.file(
    'https://gist.githubusercontent.com/walkerke/da941dac84f730adcdde/raw/c65cd4886c10df032c0d3fdf1e430d583fa8c15a/tarrxy.geojson',
    'tarrxy.geojson'
  )
}
tarrxy <- geojson_read('tarrxy.geojson', what = 'sp')

ui <- fluidPage(
  
  titlePanel("Linked brushing with Plotly and Leaflet in Shiny"),
  
  fixedRow(
    column(width = 6, 
           plotlyOutput('scatter'))
  ), 
  
  fixedRow(
    column(width = 6, 
           leafletOutput('map'))
  )
  
)


server <- function(input, output, session) {
  
  output$scatter <- renderPlotly({
    
    g <- ggplot(tarrxy@data, aes(x = pctwhite, y = pctrep)) + 
      geom_point() + 
      xlab('Percent non-Hispanic white, 2010') +
      ylab('Percent voting Republican, 2012')
    
    ggplotly(g, source = 'source') %>% layout(dragmode = 'lasso')
    
  })
  
  selected_precincts <- reactive({
    
    eventdata <- event_data('plotly_selected', source = 'source')
    
    precincts <- as.numeric(eventdata[['pointNumber']])
    
    sub <- tarrxy[tarrxy$id %in% precincts, ]
    
    return(sub)
    
  })
  
  output$map <- renderLeaflet({
    
    tarrant_map <- leaflet() %>%
      addProviderTiles('CartoDB.DarkMatter') %>%
      addPolygons(data = tarrxy, weight = 1, smoothFactor = 0.2,
                  color = 'white', fillColor = 'grey') %>%
      addPolygons(data = selected_precincts(), fill = FALSE, color = '#FFFF00',
                  opacity = 1)
    
    tarrant_map
    
  })
}

shinyApp(ui = ui, server = server)

Very cool stuff! Thanks for sharing. You have this setup to update leaflet based upon some ggplot brushing...what about updating ggplot based upon leaflet brushing?

Using source = 'source' on line 58 seems to be breaking the code for me.
The code works perfectly fine when this argument is omitted.