小叶R中的分组层控制

Question

Leaflet JS有一个插件，它允许在layer控件中对层进行分组。https://github.com/ismyrnow/Leaflet.groupedlayercontrol

这个插件似乎不存在于Leaflet R，但我发现这篇文章说在Leaflet R中有一种使用任意Leaflet JS插件的方法。https://gist.github.com/jcheng5/c084a59717f18e947a17955007dc5f92

我尝试将此方法应用于Leaflet.groupedlayercontrol插件，但没有成功。您是否知道如何使用此插件或其他方式在Leaflet R生成的layercontrol中对层进行分组？谢谢。

Answer 1

你绝对可以在leafletR中做图层控制。如果您的版本没有它，那么您需要更新，可能是从最新的GITHUB版本。

我现在正在制作一张有图层控件的地图，请看照片。下面是实现它的代码。正如您所看到的，每个addPolygons都有一个group = " A Name"，这是您在我的图像上标识复选框中的层的位置。

map<-leaflet()%>%
addTiles()%>%
addPolygons(data = plotMerge,
            fillColor = ~pal(plotMerge$incomePerCapita),
            color = "#000000", #this is an outline color
            fillOpacity = 0.8,
            group="Tract",
            weight = 0.2,
            popup=popup)%>%
addPolygons(data = countyPoly,
            fillColor = "transparent",
            color = "#000000", #this is an outline color
            fillOpacity = 0.8,
            group="County",
            popup=countyPoly@data$NAME,
            weight = 2)%>%
addPolygons(data = townPoly,
            fillColor = "transparent",
            color = "#000000", #this is an outline color
            fillOpacity = 0.8,
            group="Town",
            weight = .8,
            popup=townPoly@data$TOWN)%>%
addPolygons(data = rphnPoly,
            fillColor = "transparent",
            color = "#000000", #this is an outline color
            fillOpacity = 0.8,
            group="Public Health Region",
            weight = .8,
            popup=rphnPoly@data$PHN)%>%
addLegend(pal = pal,
          values  = plotMerge$incomePerCapita,
          position = "bottomright",
          title = "State-wide Income Percentiles",
          labFormat = labelFormat(digits=1))%>%
addLayersControl(
          overlayGroups =c("County", "Town", "Public Health Region", "Tract"),
          options = layersControlOptions(collapsed=FALSE)
          )
saveWidget(map, file="map1.html", selfcontained=FALSE)

下面是它看起来的样子：

​

您还可以添加其他控件，请在此处查看：

Leaflet R Hidden Layers

Answer 2

我知道这是一个古老的问题，但我在其他地方找不到好的答案-这可能会在未来帮助其他人。

下面是一个带有注释的reprex，用于解释代码：

#load library
library(tidyverse)
library(leaflet)

#load data
data("quakes")

#map all points
# quakes %>% 
#   leaflet() %>% 
#   addProviderTiles(providers$CartoDB.Positron) %>% 
#   addCircleMarkers(lng = ~long, lat = ~lat, radius = 1)

#create a grouping variable -- this can be whatever you want to filter by 
quakes <- quakes %>% 
  mutate(groups = case_when(
    stations < 30 ~ 1,
    stations < 50 ~ 2,
    TRUE ~ 3
  ))


#function to plot a map with layer selection 
map_layers <- function() {

  #number of groups
  k <- n_distinct(quakes$groups)

  #base map
  map <- leaflet() %>%
    addProviderTiles(providers$CartoDB.Positron)

  #loop through all groups and add a layer one at a time
  for (i in 1:k) {
    map <- map %>% 
      addCircleMarkers(
        data = quakes %>% filter(groups == i), group = as.character(i),
        lng = ~long, lat = ~lat, radius = 1
      )
  }

  #create layer control
  map %>% 
    addLayersControl(
      overlayGroups = c(1:k),
      options = layersControlOptions(collapsed = FALSE)) %>% 
    hideGroup(as.character(c(2:k))) #hide all groups except the 1st one

}

#plot the map
map_layers()