代码之家 › 专栏 › 技术社区 › Jio

使用sliderInput在R中动态渲染choropleth贴图

leaflet shiny r

1

Jio · 技术社区 · 7 年前

我有一个shapefile,我正在使用readOGR将其读入R,以将其转换为SpatialPolygonDataframe。属性表如下图所示。

每一行是一个区域(邮政编码区域),一天中的每一小时都有值,例如:h_0、h_1、…h_23。在我闪亮的应用程序中,我想显示一张地图,当用户使用sliderInput小部件选择特定的小时时,地图会发生变化。闪亮的应用程序如下所示:

产生上述结果的代码如下所示:

 library(shiny)
 library(leaflet)
 library(reshape2)
 library(maps)
 library(mapproj)
 library(rgdal)
 library(RColorBrewer)
 library(sp)
 library(rgeos)



ui <- fluidPage(

 titlePanel("Title"),

 sidebarLayout(

 sidebarPanel(
   tabsetPanel(id= "tabs",

              tabPanel("Map", id = "Map", 
                       br(), 

                       p("Choose options below to interact with the Map"), 

                       sliderInput("hour", "Select the hours", min = 0 , max = 23, 
                                   value = 7, step = 1, dragRange= TRUE)
                       )
  )
),

mainPanel(

  tabsetPanel(type= "tabs",


              tabPanel("Map", leafletOutput(outputId = "map"))
          )
  )
 )
 )



 server <- function(input, output) {


  layer <- reactive( {

      shp = readOGR("shp",layer = "attractiveness_day3")
      shp_p <- spTransform(shp, CRS("+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"))

  })

 output$map <- renderLeaflet({
     bins<- c(0, 2000, 4000, 8000, 16000, Inf)
    pal <- colorBin("YlOrRd", domain = layer()$h_7, bins = bins)

    leaflet(layer()) %>% 
    setView(13.4, 52.5, 9) %>% 
    addTiles()%>%
      addPolygons( 
        fillColor = ~pal(h_7),
        weight = 0.0,
        opacity = 1,
        color = "white",
        dashArray = "3",
        fillOpacity = 0.7 
      )  %>% 
      addLegend(pal = pal, values = ~h_7, opacity = 0.7, title = NULL, position = "bottomright")


  })
  #until here it works but onwards not. 
 observe(leafletProxy("map", layer())%>%
           clearShapes()%>%
           addPolygons( 
             fillColor = ~pal(h_7),  # is it possible here to pass column name dynamically
             weight = 0.0,
             opacity = 1,
             color = "white",
             dashArray = "3",
             fillOpacity = 0.7 
           )  %>% 
           addLegend(pal = pal, values = ~h_7, opacity = 0.7, title = NULL, position = "bottomright")
 )

}


shinyApp(ui, server)

因此,当前choropleth映射填充了column的值 h_7 静态选择。但我不知道如何以及是否可以根据sliderInput选择动态传递列名(例如,如果sliderInput值为8,则对应的列为h_8)。然后根据从反应函数传递到 observe leafletProxy 功能。

样本数据: sample data

1 回复 | 直到 7 年前

1

2

Wilmar van Ommeren 7 年前

leafletProxy 可以使用链接到列值 dataset[[column_name]] . 使用单个方括号,不仅可以选择值,还可以选择相应的多边形。

要使应用程序正常工作,您需要致电 layer() 外面功能。此外,使用 clearControls() 删除重复的图例。

reactive 表情。如果您只是将其作为变量添加到 server

 observeEvent({input$hour},{
    hour_column <- paste0('h_',input$hour)
    data = layer()[hour_column]
    pal <- colorBin("YlOrRd", domain = as.numeric(data[[hour_column]]), bins = bins)
    leafletProxy("map", data=data)%>%
      clearShapes()%>%
      addPolygons( 
        fillColor = pal(as.numeric(data[[hour_column]])),  
        weight = 0.0,
        opacity = 1,
        color = "white",
        dashArray = "3",
        fillOpacity = 0.7 
      )  %>% clearControls() %>%
      addLegend(pal = pal, values =as.numeric(data[[hour_column]]), opacity = 0.7, title = NULL, position = "bottomright")
  })