leaflet for R(3)——leaflet.extras

王致远

2018/09/29

11 leaflet.extras

11.1 addHeatmap

library(leaflet)
library(leafletCN)
library(leaflet.extras)
library(magrittr)
leaflet(quakes) %>% addProviderTiles(providers$Esri.WorldImagery) %>%
  setView( 178, -20, 5 ) %>%
    addHeatmap(lng = ~long, lat = ~lat, intensity = ~mag,
               blur = 20, max = 0.05, radius = 15)
+−
Leaflet | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, and the GIS User Community
library(sp)
jsURL <- 'https://rawgit.com/Norkart/Leaflet-MiniMap/master/example/local_pubs_restaurant_norway.js'
v8 <- V8::v8()
v8$source(jsURL)
geoJson <- geojsonio::as.json(v8$get('pubsGeoJSON'))
spdf <- geojsonio::geojson_sp(geoJson)

leaflet(spdf) %>%
  addProviderTiles(providers$Thunderforest.TransportDark) %>%
  addHeatmap(blur = 20, max = 0.05, radius = 15)
  
leaflet(spdf) %>%
  addProviderTiles(providers$Thunderforest.Transport) %>%
  addHeatmap(blur = 20, max = 0.05, radius = 15, gradient = 'Greys')
  
london.crimes.files <- Sys.glob(
  paste0(system.file('examples/data/London-Crimes', package='leaflet.extras'),
         '/*/*-city-of-london-street.csv.zip'))
london.crimes <- suppressMessages(
  purrr::map(
    london.crimes.files,
    ~readr::read_csv(.) %>%
      dplyr::select(Latitude, Longitude) %>%
      dplyr::filter(!is.na(Latitude))) %>%
  magrittr::set_names(basename(Sys.glob(
    paste0(system.file('examples/data/London-Crimes', package='leaflet.extras'),
           '/2016*')))))

leaf <- leaflet() %>%
  addProviderTiles(providers$CartoDB.Positron)

purrr::walk(
  names(london.crimes),
  function(month) {
    leaf <<- leaf %>%
      addHeatmap(
        data = london.crimes[[month]],
        layerId = month, group = month,
        lng=~Longitude, lat=~Latitude,
        blur = 20, max = 0.05, radius = 15)
  })

leaf %>%
  setView(-0.094106, 51.515, 14) %>%
  addLayersControl(
    baseGroups = names(london.crimes),
    options = layersControlOptions(collapsed = FALSE)
  )

11.2 addWebGLHeatmap

案例一

Just by number of quakes

leaflet(quakes) %>% addProviderTiles(providers$Esri.WorldImagery) %>%
  addWebGLHeatmap(lng=~long, lat=~lat, size = 60000)
+−
Leaflet | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, and the GIS User Community

By magnitude

leaflet(quakes) %>% addProviderTiles(providers$Esri.WorldImagery) %>%
  addWebGLHeatmap(lng=~long, lat=~lat, intensity = ~mag, size=60000)
+−
Leaflet | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, and the GIS User Community

案例二

library(sp)
jsURL <- 'https://rawgit.com/Norkart/Leaflet-MiniMap/master/example/local_pubs_restaurant_norway.js'
v8 <- V8::v8()
v8$source(jsURL)
geoJson <- geojsonio::as.json(v8$get('pubsGeoJSON'))
spdf <- geojsonio::geojson_sp(geoJson)

Size in meters

leaflet(spdf) %>%
  addProviderTiles(providers$Esri.WorldImagery) %>%
  addWebGLHeatmap(size=60000)

Size in Pixels

leaflet(spdf) %>%
  addProviderTiles(providers$Esri.WorldImagery) %>%
  addWebGLHeatmap(size=25,units='px')

案例三

library(dplyr)
## 
## 载入程辑包：'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
jsURL <- 'http://leaflet.github.io/Leaflet.markercluster/example/realworld.10000.js'
v8 <- V8::v8()
v8$source(jsURL)

df <- data.frame(v8$get('addressPoints')[,c(1,2)], stringsAsFactors = F) %>%
  dplyr::mutate_each(dplyr::funs(as.numeric))
## `mutate_each()` is deprecated.
## Use `mutate_all()`, `mutate_at()` or `mutate_if()` instead.
## To map `funs` over all variables, use `mutate_all()`
colnames(df) <- c('lat','lng')

Size in Meters

leaflet(df) %>%
  addTiles() %>%
  addWebGLHeatmap(lng=~lng, lat=~lat,size=1000)

Size in Pixels

leaflet(df) %>%
  addTiles() %>%
  addWebGLHeatmap(lng=~lng, lat=~lat,size=20,units='px')