r - 如何在 R 的传单中的 "addTiles"之上 "addPolygons"？

Question

您如何在 R 的传单包中设置图层顺序，以便瓷砖显示在填充颜色的多边形顶部？

这是我到目前为止所得到的:

require(leaflet)
require(acs)
require(tigris)
require(rgdal)
census.income.end.year = 2015
county = 17
nd.counties=acs.fetch(geography=geo.make(state="ND", county=county), 
                      table.number="B01003", endyear = 2015)

tracts <- tigris::tracts(state = 'ND', county = county, cb=FALSE, year = 2015)

# create a geographic set to grab tabular data (acs)
geo<-geo.make(state=c("ND"),
              county = county,
              tract="*")

# add in median income
median.income <- acs.fetch(endyear = census.income.end.year, 
                           geography = geo, 
                           variable = c("B19013_001"))
income_df <- data.frame(paste0(as.character(median.income@geography$state), 
                               str_pad(as.character(median.income@geography$county), 3, 'left', '0'), 
                               str_pad(as.character(median.income@geography$tract), 5, 'left', '0')), 
                        median.income@estimate)

rownames(income_df)<-1:nrow(income_df)
names(income_df)<-c("GEOID", "hhincome")
income_merged <- geo_join(tracts, income_df, "GEOID", "GEOID")

income_merged <- spTransform(income_merged, CRS("+init=epsg:4326"))

qpal <- colorQuantile("plasma", income_df$hhincome, n = 4)

leaflet() %>% 
  setView( -96.7898, 46.8772, zoom=11) %>% 
  addPolygons(data = income_merged, 
              fillColor = qpal(income_merged$hhincome), 
              fillOpacity = 1, 
              weight = 0.3) %>%
  addProviderTiles(providers$Hydda.RoadsAndLabels) 

最终，我想使用自定义 MapBox 使用 addTiles(而不是上面代码中的 addProviderTiles)来执行此操作，但我无法弄清楚如何使该示例可重现...假设您需要一个 key 访问自定义 MapBox 瓦片(顺便说一句，我创建了一个自定义 MapBox 瓦片，除了道路和标签之外应该是透明的，因此底层多边形应该“显示”。)

这是使用非 R 版本的传单在圆圈顶部添加图 block 的一种方法: http://jsfiddle.net/dcu9pz2w/ ，但我不知道如何在我的上下文中使其工作。我认为添加“ Pane ”可能是要走的路，但我在 R 传单中看不到该功能。另外，我探索了 z-index 值，但这似乎是一个死胡同。

任何帮助深表感谢!

Answer 1

R 传单现在包括 addMapPane 功能。此问题的解决方案是首先设置 Pane 顺序，然后添加图 block /多边形。可重现的例子:

library(leaflet)
library(geojsonio)

# get polygon data
# https://github.com/simonepri/geo-maps/blob/master/info/countries-land.md
world <- geojson_read(
  "https://github.com/simonepri/geo-maps/releases/download/v0.6.0/countries-land-10km.geo.json", 
  what = "sp"
)

# generate random values
world@data$value <- runif(nrow(world@data))

# get color palette
color_pal <- colorNumeric(palette = "YlOrRd", domain = NULL)

# get leaflet map
leaflet() %>%
  setView(lat = 50, lng = 15, zoom = 4) %>%
  addMapPane("background_map", zIndex = 410) %>%  # Level 1: bottom
  addMapPane("polygons", zIndex = 420) %>%        # Level 2: middle
  addMapPane("labels", zIndex = 430) %>%          # Level 3: top
  addProviderTiles(
    providers$Esri.WorldTerrain,
    options = pathOptions(pane = "background_map")
  ) %>%
  addPolygons(
    data = world, stroke = FALSE, smoothFactor = 0.2,
    fillOpacity = 0.6, fillColor = ~color_pal(value),
    options = pathOptions(pane = "polygons")
  ) %>%
  addProviderTiles(
    providers$Stamen.TonerLabels,
    options = pathOptions(pane = "labels")
  )