基于r传单中用户输入的颜色映射数值

Question

我想根据用户的滑动输入范围为形状文件中的人口图着色，但是当我尝试根据用户的输入来对数据进行子集化时，我一直遇到空间多边形数据帧格式错误。从底图中选择表示满足上述条件的200到1000个多边形。DOWNLOAD SHAPE FILE HERE代码：

library(shiny)
library(leaflet)
library(rgdal)
library(RColorBrewer)

#loading LIAs shape file
mp<-readOGR(
  dsn="C:/LIAs",
  layer="m1",encoding = 'UTF-8')

ui<-fluidPage(

  leafletOutput("leaf",height = 600),

  # Slider input range 
  sliderInput(inputId = "pop",
              label = "Population Per km2:",
              min = 1, max = 155000,
              value = c(1,15000)

  )
)

server<-function(input,output){

  #Base map(default)

  output$leaf<-renderLeaflet({

    leaflet(mp) %>%

      #default map
      #Add default OpenStreetMap map tiles
      addTiles()%>%

      # lias polygons
      addPolygons(
        data = mp,
        fillColor = "blue",
        weight = 1, smoothFactor = 0.5,
        opacity = 1.0, fillOpacity = 1.0
      ) 

      })
  #slider input observe event function for population per km2
  observeEvent(input$pop, {
    pal1 <- colorBin("YlOrRd", mp$PpDnsty, bins=15, na.color = "#bdbdbd")
    leafletProxy("leaf") %>%
      # clearMarkers() %>%
      clearControls() %>%
      clearShapes()%>%
      addPolygons(
        data = mp[mp$PpDnsty == input$pop, ],
        weight = 1, smoothFactor = 0.5,
        opacity = 1.0, fillOpacity = 1.0,
        fillColor = ~pal1(PpDnsty)
      )%>%
      addLegend(title = "Population Per km2", position = "topleft",
                pal = pal1, values = ~PpDnsty, opacity = 1)
  })
}


shinyApp(ui,server)