如何在同一个 Rshiny 图中添加两个不同的标记

Question

我试图在同一个 Rshiny 图中包含两种不同类型的标记。第一个标记（addCircleMarkers）工作得很好，但是当我包含第二个标记（addMarkers）时，我收到了错误消息

我的数据框：

  Type Location.ID             Location_discription      Lat      Long Flood.path       FP_Icon Sample Structure.2
1 GBS_S         ALB                       Albany, OR 44.62054 -123.1039        Yes greenleafIcon     A1        Blue
2 GBS_S         ALB                       Albany, OR 44.62054 -123.1039        Yes greenleafIcon     A3        Blue
3 GBS_S         ALB                       Albany, OR 44.62054 -123.1039        Yes greenleafIcon     A4        Blue
4 GBS_S         ALB                       Albany, OR 44.62054 -123.1039        Yes greenleafIcon     A5        Blue
5 GBS_S         ANG Angels' rest, Columbia Gorge, OR 45.56383 -122.1523        Yes greenleafIcon   ANG1        Blue
6 GBS_S         ANG Angels' rest, Columbia Gorge, OR 45.56383 -122.1523        Yes greenleafIcon  ANG1b        Blue
  Structure.3
1       Green
2       Green
3       Green
4       Green
5       Green
6       Green

我的 ui.R

library(shiny)
library(leaflet)

shinyUI(fluidPage(

  # Application title
  titlePanel("Aspen GBS Population Structure results on map"),

  # Side bar layout
  sidebarLayout(
    sidebarPanel(
      selectInput("structure", label = "Select K for display", choices = c("2", "3", "4", "5", "6"), selected = "2"),
      radioButtons("origin", label = "Nature of the sample", choices = c("Flood", "Non Flood"), selected = "Flood")),

  mainPanel(
    leafletOutput("map")
  )
  )
)
)

我的服务器.R

greenleafIcon <- makeIcon(
  iconUrl = "http://leafletjs.com/docs/images/leaf-green.png",
  iconWidth = 20, iconHeight = 50,
  iconAnchorX = 12, iconAnchorY = 84,
  shadowUrl = "http://leafletjs.com/docs/images/leaf-shadow.png",
  shadowWidth = 40, shadowHeight = 54,
  shadowAnchorX = 3, shadowAnchorY = 52
)

redleafIcon <- makeIcon(
  iconUrl = "http://leafletjs.com/docs/images/leaf-red.png",
  iconWidth = 20, iconHeight = 50,
  iconAnchorX = 12, iconAnchorY = 84,
  shadowUrl = "http://leafletjs.com/docs/images/leaf-shadow.png",
  shadowWidth = 40, shadowHeight = 54,
  shadowAnchorX = 3, shadowAnchorY = 52
)

library(shiny)

shinyServer(function(input, output) {
    dt <- reactive(
        switch(input$structure,
              "2" = data_K2$Structure.2,
              "3" = data_K2$Structure.3))

    dt2 <- reactive(
      switch (input$origin,
        "Flood" = data_K2$FP_Icon,
        "Non Flood" = data_K2$FP_Icon))

    output$map <- renderLeaflet(
      leaflet(data = data_K2) %>% addTiles() %>% setView(lng = -106.1039361,lat = 50.543981, zoom = 4) %>% 
      addCircleMarkers(lat = ~Lat, lng = ~Long, popup = ~Location_discription, radius=2, color = ~dt(), fill = TRUE) %>%
      addMarkers(lat = ~Lat, lng = ~Long, popup = ~Location_discription, icon = ~dt2())
    )
})

我收到的错误消息是 - Error in icon$iconUrl : $ operator is invalid for atomic vectors

我在哪里做错了？

Answer 1

问题所在的行在这里：

addMarkers(lat = ~Lat, lng = ~Long, popup = ~Location_discription, icon = ~dt2())

特别是~dt2()。这计算为data_K2$FP_Icon，它是一个原子向量。向量不能用$ 进行子集化。 addMarkers 的 icon 参数需要一个具有子集 iconUrl 的对象，因此会出现错误。

我认为你想要的是：

leafIcons <- icons(
  iconUrl = ifelse(data_K2$FP_Icon == "greenleafIcon",
    "http://leafletjs.com/docs/images/leaf-green.png",
    "http://leafletjs.com/docs/images/leaf-red.png"
  ),
  iconWidth = 38, iconHeight = 95,
  iconAnchorX = 22, iconAnchorY = 94,
  shadowUrl = "http://leafletjs.com/docs/images/leaf-shadow.png",
  shadowWidth = 50, shadowHeight = 64,
  shadowAnchorX = 4, shadowAnchorY = 62
)

然后

addMarkers(lat = ~Lat, lng = ~Long, popup = ~Location_discription, icon = leafIcons

这里有非常有用且清晰的文档：https://rstudio.github.io/leaflet/markers.html