CODEWITHSUNDEEP
rcolorsleafletpolygons
statsguy
statsguy

Reputation: 123

R Leaflet GeoJSON Coloring

I am still working on this R Leaflet self project to learn and I'm trying to color in some Polygons in the Wake County area of Raleigh, NC. Below is the image of what I am trying to color.

https://i.sstatic.net/c8igf.jpg

Basically I am trying to get each of those polygons colored differently. I've tried addPolygons but I guess I didn't have correct Polygon data. I've looked at color binning but I seem to be out of ideas. Below is my code. I even tried to unnest the GeoJSON data and create a factor palette but that hasn't seemed to work.

library(shiny)
library(leaflet.extras)
library(geojsonio)
library(rgdal)

dataurl <- 'https://opendata.arcgis.com/datasets/f5c3b84a6fcc499d8f9ece78602258eb_0.geojson'
data <- geojson_read(dataurl, method = 'web', parse = FALSE, what = 'list')

wake <- readOGR(dataurl)
wake$zips <- factor(sample.int(39L, nrow(wake), TRUE))

#bikedata <- 'D:/bicycle-crash-data-chapel-hill-region.geojson'
#bike <- geojson_read(bikedata)

vtdata <- 'http://geodata.vermont.gov/datasets/4c206846699947429df59c8cb552ab5c_11.geojson'
vt <- geojson_read(vtdata)

factpal <- colorFactor(topo.colors(39), wake$zips)

ui <- shinyUI(
    fluidPage(
        leafletOutput("map", width = "100%", height = "900px")
    )
)

server <- function(input, output) {

    wakegeojson <- reactive({
        data
    })

    #bikegeojson <- reactive({
    #    bike
    #})

    vtgeojson <- reactive({
        vt
    })

    output$map <- renderLeaflet({
        leaflet() %>%
            addTiles() %>%
            setView(-93.65, 42.0285, zoom = 4)

    })

    observe({
        leafletProxy("map") %>%
            addWMSTiles("http://mesonet.agron.iastate.edu/cgi-bin/wms/nexrad/n0r.cgi",
            layers = "nexrad-n0r-900913",
            options = WMSTileOptions(format = "image/png", transparent = TRUE),
            attribution = "") %>%
            addGeoJSON(wakegeojson(), weight = 3, fill = factpal) %>%
            #addGeoJSON(bikegeojson()) %>%
            addGeoJSON(vtgeojson(), fill = FALSE, color = "black")
    })
}

app <- shinyApp(ui = ui, server = server)
runApp(app, launch.browser = TRUE)

I think I need to explore the addPolygons feature more but I'm not exactly sure how to do that or how to parse/unnest my GeoJSON data in order to accomplish filling in the Wake County Zipcodes with different colors. Any help is always appreciated. Thank you.

Upvotes: 3

Views: 1063

Answers (1)

SeGa
SeGa

Reputation: 9809

I would switch to sf. You can directly load the geojson and produce a Multipolygon and a Multilinestring object which will also read much faster than readOGR.

Then you can just put those objects in addPolygons and addPolylines.

The following example should work:

library(shiny)
library(leaflet.extras)
library(geojsonio)
library(rgdal)
library(sf)

dataurl <- 'https://opendata.arcgis.com/datasets/f5c3b84a6fcc499d8f9ece78602258eb_0.geojson'
wake <- st_read(dataurl)
wake$zips <- factor(sample.int(39L, nrow(wake), TRUE))

vtdata <- 'http://geodata.vermont.gov/datasets/4c206846699947429df59c8cb552ab5c_11.geojson'
vt <- st_read(vtdata)

factpal <- colorFactor(topo.colors(39), wake$zips)

ui <- shinyUI(
  fluidPage(
    leafletOutput("map", width = "100%", height = "900px")
  )
)

server <- function(input, output) {

  wakegeojson <- reactive({
    wake
  })

  vtgeojson <- reactive({
    vt
  })

  output$map <- renderLeaflet({
    leaflet() %>%
      addTiles() %>%
      addPolygons(data=wakegeojson(), color=factpal(wake$zips)) %>%
      addPolylines(data=vtgeojson(), color="red")
  })
}

app <- shinyApp(ui = ui, server = server)
runApp(app, launch.browser = TRUE)

Upvotes: 4

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