leaflet_map.R

Leaflet interactive visualisation of UK RSEs

pkgs

if (!require("pacman")) install.packages("pacman")

## Loading required package: pacman

pkgs <- c("leaflet", "tidyverse","sp", "spatstat", "wesanderson")
pacman::p_unload(pacman::p_loaded(), character.only = T)

## The following packages have been unloaded:
## pacman, webshot, knitr, rmarkdown

pacman::p_load(pkgs, character.only = T)

custom functions

cap_first https://gist.github.com/annakrystalli/70820dbfd0457601ddd0203dcc3a8476

cap_first <- function(X){
    simple_cap <- function(x) {
        s <- strsplit(x, " ")[[1]]
        out <- paste(toupper(substring(s, 1,1)), substring(s, 2),
                     sep="", collapse=" ")
        out <- gsub("And", "and", out)
        out <- gsub("&", "and", out)
        out <- gsub("Of", "of", out)
        out
    }
    sapply(X, simple_cap, USE.NAMES = F) 
}

get_radius used to get radius to correctly represent relative area of circles, consistent with the concept of proportional ink as discussed in Calling Bull*** tutorial

get_radius <- function(area){
    sqrt(area/pi)
}

data

pc_coords <- read_csv("data/ukpostcodes.csv") # source: https://www.freemaptools.com/download-uk-postcode-lat-lng.htm

## Parsed with column specification:
## cols(
##   id = col_integer(),
##   postcode = col_character(),
##   latitude = col_double(),
##   longitude = col_double()
## )

rse_pc <- read_csv("data/RSE_email_postcode.csv") %>% 
    set_tidy_names(syntactic = T) %>% 
    rename(postcode = Unique.postcodes) 

## Parsed with column specification:
## cols(
##   Count = col_integer(),
##   `Unique postcodes` = col_character(),
##   Name = col_character()
## )

## New names:
## Unique postcodes -> Unique.postcodes

data process

ammend NA postcodes

rse_pc[rse_pc$postcode == "EH9 3JZ", "postcode"] <- "EH8 9AB"
rse_pc[rse_pc$postcode == "BS16 1QU", "postcode"] <- "BS2 0JA"

join lat/lon from postcodes

rse_pc <- rse_pc %>% left_join(pc_coords, by = "postcode")

convert to spdf

spdf <- SpatialPointsDataFrame(coords = rse_pc[,c("longitude", "latitude")], data = rse_pc,
                       proj4string = CRS("+proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0"))

---

INTERACTIVE LEAFLET PLOTS

Basic

m <- leaflet(data = spdf) %>% addProviderTiles(providers$OpenStreetMap, group = "OSM") %>% addMarkers()
m    

RSE count ~ size of circle

use parameter size to multiply proportional areas by a constant.

size <- 4

RSE count indicated by size of circle, single colour. Hover over institutional info

leaflet(data = spdf) %>% addProviderTiles(providers$OpenStreetMap, group = "OSM") %>% 
    addCircleMarkers(radius = ~get_radius(Count)*size, fillOpacity = 0.5,
                     label = ~paste0(cap_first(Name), " (", Count, ")"),
                     color = wes_palette("GrandBudapest")[2])

RSE count ~ size of circle + colour scale

RSE count indicated by size of circle as well as colour scale. Hover over institutional info. Colour palette from wesanderson package. use parameter size to multiply proportional areas by a constant.

size <- 4
# create palette
pal <- colorNumeric(
    palette = as.character(wes_palette("Darjeeling")[c(2,3,4,1)]),
    domain = spdf$Count)

leaflet(data = spdf) %>% addProviderTiles(providers$OpenStreetMap, group = "OSM") %>% 
    addCircleMarkers(radius = ~get_radius(Count)*size, fillOpacity = 0.7, 
                     color = ~pal(Count),
                     stroke = FALSE,
                     label = ~paste0(cap_first(Name), " (", Count, ")")) %>%
    addLegend("bottomright", pal = pal, values = ~Count,
              title = "RSE counts",
              opacity = 1)

Special ICON

Make a custom icon. See more here

leafIcons <- icons(
    iconUrl = "http://leafletjs.com/examples/custom-icons/leaf-green.png",
    iconWidth = 38, iconHeight = 95,
    iconAnchorX = 22, iconAnchorY = 94,
    shadowUrl = "http://leafletjs.com/examples/custom-icons/leaf-shadow.png",
    shadowWidth = 50, shadowHeight = 64,
    shadowAnchorX = 4, shadowAnchorY = 62
)

INTERACTIVE LEAFLET PLOT

leaflet(data = spdf) %>% addProviderTiles(providers$OpenStreetMap, group = "OSM") %>% addMarkers(icon = leafIcons)