Leaflet R – How to Add Layers from Different Spatial Data Frames in R

leaflet-rr

Very new to R's Leaflet package and have two spatial data frames.

1) An outline of a city
2) Its major highways

I wish to show both of these on the same map. I get how to do this with ggmap or tmap. I'm little confused when it comes to Leaflet.

Here is some code that takes public data:

toronto – an outline of the city
all_roads – Toronto's road network

I then view each separately with Leaflet. How do I view multiple layers from different spatial data frames on the same map?

library(sf)
library(leaflet)

# Read in Toronto boundaries as a spatial data frame
# WGS84 latitude and longitude
# Data: https://www.toronto.ca/city-government/data-research-maps/open-data/open-data-catalogue/#4a30ca3e-70f0-bf79-1e76-459ebda8458c
toronto <- st_read("/Users.../torontoBoundary_wgs84/citygcs_regional_mun_wgs84.shp")

# Read in street data
# (WGS84 projection)
# https://portal0.cf.opendata.inter.sandbox-toronto.ca/dataset/toronto-centreline-tcl-2/
all_roads <- st_read("/Users.../centreline_wgs84/CENTRELINE_WGS84.shp") 

# Just highways
xway <- filter(all_roads, FCODE_DESC == "Expressway")

map <- leaflet(data = hood_shp, options = leafletOptions(minZoom = 11, maxZoom = 13))
map %>% addPolygons(color = "#aaaaaa", weight = 1.0, smoothFactor = 0.5,
                    opacity = 1.0, fillOpacity = 0.7)

highway <- leaflet(data = xway)
highway %>% addPolygons(color = "brown", weight = 1.0, smoothFactor = 0.5,
                        opacity = 1.0, fillOpacity = 0.7)

Best Answer

simply, dont add the dataset in the leaflet() function:

leaflet() %>% addProviderTiles("CartoDB.Positron") %>%
    addPolygons(data=tonto, fillOpacity = 0.7,weight = 1.2, etc....)%>%
    addPolygons(data=xway, fillOpacity = 0.7,weight = 1.2etc....)

but you should also consider, perhaps along the line, having the basemap as something very simple such as:

output$map <- renderLeaflet({
    leaflet() %>%
      setView(lng = -3.8, lat = 54.8, zoom = 6) %>%
      addProviderTiles("CartoDB.DarkMatter", layerId = "basetile",options = providerTileOptions(minZoom = 6))
  })

and then you can add layers with observeEvents, buttons, tick boxes etc etc using leafletProxy();

leafletProxy("map", data = selectedstuff()) %>%
                        clearShapes() %>%
                        addPolygons(fillColor =  "red",
                                    popup = state_popup,
                                    color = "#BDBDC3",
                                    fillOpacity = 1,
                                    weight = 1)

have a google around for the latter, there's loads on the help pages and on this website

Rstudio leaflet help page for leafletproxy this answer (plus many more) might give you more insight into leafletproxy

Related Solutions

Vector Layers Order in Leaflet-R – How to Manage Layers

This is possible with the latest leaflet version from github. They've introduced a function called addMapPane which gives full control over individual layer ordering. Here's an example:

# devtools::install_github("rstudio/leaflet")

library(mapview) # for the data
library(leaflet)
library(sf)      # for data wrangling
library(dplyr)   # for data wrangling

# create some borders
borders = franconia %>%
  group_by(district) %>%
  summarise() %>%
  st_cast("MULTILINESTRING")

# create a map with individual layer ordering using addMapPane
leaflet() %>%
  addTiles() %>%
  addMapPane("polygons", zIndex = 410) %>%
  addMapPane("borders", zIndex = 420) %>%
  addPolygons(data = franconia, group = "franconia", weight = 2,
              options = pathOptions(pane = "polygons")) %>%
  addPolylines(data = borders, group = "district", color = "black",
               opacity = 1, options = pathOptions(pane = "borders")) %>%
  addLayersControl(overlayGroups = c("franconia", "district"))

Of course, in your example map you're overlaying two polygon layers so you will need to decide which one of those should be on top. You cannot have just the borders of a polygon layer overlay the other but not the fill... I suggest you create a 3rd layer with only the borders added via addPolylines and have that in the pane with the highest zIndex similar to the example above.

Leaflet for R – Displaying Multiple Data Rows in Popup

First, I think it's a conceptual problem because you have repeated points with different data in the same location, e.g .: Angelsberg and Asselborn locations. So the popup from addMinicharts function will show you n pie charts in the same location, maybe one above the other. So, when you click on the pie chart you can only get the most upper layer.

Briefly, I followed these steps:

Add shiny library to use the tag element
Transform the data: combine all the available data in each location/point
Please check that I execute the mean function to aggregate the data in var1, var2 and var3. I don't know if doing this was correct because that depends in the nature of your data.

Check the commented and reproducible code below.

### data ###
d <- structure(
  list(
    area_name = c(
      "Alscheid",
      "Alzingen",
      "Angelsberg",
      "Angelsberg",
      "Angelsberg",
      "Arsdorf",
      "Asselborn",
      "Asselborn",
      "Baastenduerf",
      "Bartringen"
    ),
    surveyID1 = c(1510L, 24L, 382L, 1429L, 1061L, 526L, 1524L, 1281L, 2169L, 1292L),
    Alter = c(
      "25 bis 34",
      "25 bis 34",
      "15 bis 24",
      "15 bis 24",
      "25 bis 34",
      "15 bis 24",
      "35 bis 44",
      "35 bis 44",
      "25 bis 34",
      "25 bis 34"
    ),
    latitude = c(
      49.970094,
      49.56885,
      49.76374,
      49.76374,
      49.76374,
      49.860547,
      50.09624,
      50.09624,
      49.891134,
      49.6038
    ),
    longitude = c(
      6.007703,
      6.16394,
      6.1592,
      6.1592,
      6.1592,
      5.842195,
      5.97425,
      5.97425,
      6.164145,
      6.0782
    ),
    count_all_variants = c(1, 1, 3, 3, 3, 1, 2, 2, 1, 1),
    var1 = c(1L, 1L, 2L, 3L, 3L, 1L, NA, NA, NA, 1L),
    var2 = c(NA, NA, 1L, NA, NA, NA, NA, NA, 1L, NA),
    var3 = c(NA, NA, NA, NA, NA, NA, 2L, 2L, NA, NA)
  ),
  row.names = c(NA, 10L),
  class = "data.frame"
)


# Transform data

# Load simple features object management library
library(sf)

# Convert to simple feature collection object (points)
d2 <- st_as_sf(d, coords = c("longitude", "latitude"))

# Get intersection of the same object
d3 <- st_intersection(d2)

# See origins columns (which elements intersects)
d3$origins

list <- lapply(1:length(d3$origins), function(x) {
  point <- d3[x, ]
  point$surveyID1 <-
    stringr::str_flatten(d2[d3$origins[[x]], ]$surveyID1, collapse = ", ")
  point$Alter <-
    stringr::str_flatten(d2[d3$origins[[x]], ]$Alter, collapse = ", ")
  point$var1 <- mean(d2[d3$origins[[x]], ]$var1, na.rm = TRUE)
  point$var2 <- mean(d2[d3$origins[[x]], ]$var2, na.rm = TRUE)
  point$var3 <- mean(d2[d3$origins[[x]], ]$var3, na.rm = TRUE)

  return(point)

})

# Bind list points
new_d <- do.call(rbind, list)
print(class(new_d)) # simple features object

# Add lat and long data as columns
new_d$longitude <- st_coordinates(new_d)[, "X"]
new_d$latitude <- st_coordinates(new_d)[, "Y"]

# Transform to data frame adding null to geometries
st_geometry(new_d) <- NULL
print(class(new_d))

### mapping ###
library(leaflet)
library(leaflet.minicharts)

tilesURL <-
  "http://server.arcgisonline.com/ArcGIS/rest/services/Canvas/World_Light_Gray_Base/MapServer/tile/{z}/{y}/{x}"

title <-
  shiny::tags$div(HTML('<h3>Fussball</h3>')) # add shiny library to use "tags"
basemap <-
  leaflet(options = leafletOptions(
    zoomControl = FALSE,
    minZoom = 9,
    maxZoom = 10,
    dragging = T
  )) %>%
  addTiles(tilesURL) %>%
  fitBounds(6.1, 49.4426671413, 6.1, 50.1280516628) %>%
  addControl(title, position = "topleft")

colors <- c('#7fc97f', '#beaed4', '#fdc086')

basemap %>%
  addMinicharts(
    new_d$longitude,
    new_d$latitude,
    type = "pie",
    chartdata = new_d[, c("var1", "var2", "var3")],
    colorPalette = colors,
    popup = popupArgs(
      labels = c("Fussball", "Futtball", "Foussball"),
      html = paste0(
        "<div>",
        "<h3>",
        new_d$area_name,
        "</h3>",
        "ID: ",
        new_d$surveyID1,
        "<br>",
        "Alter: ",
        new_d$Alter,
        "</div>"
      )
    ),
    width = 60 * sqrt(new_d$count_all_variants) / sqrt(max(new_d$count_all_variants)),
    transitionTime = 0
  )

Best Answer

Related Solutions

Vector Layers Order in Leaflet-R – How to Manage Layers

Leaflet for R – Displaying Multiple Data Rows in Popup

Related Question