相关疑难解决方法(0)

我想知道如何根据输入的变化来改变Shiny和Leaflet来绘制点,而不重绘整个地图.

我正在使用的代码是:

library(leaflet)
library(shiny)
library(dplyr)
library(readr)

ui <- fluidPage(
  titlePanel("Melbourne Urban Tree Visualisation"),
  leafletOutput("treedat"),
  uiOutput("precinct")
   #Giving an input name and listing out types to choose in the Shiny app
  )

server <- function(input, output){

  #td <- read.csv("treedata.csv", header = TRUE)

  #pal <- colorNumeric(
  #palette = "RdYlGn",
  #domain = td$LifeExpectencyValue
  #)

  output$precinct <- renderUI({

    choices <- as.character(unique(td$Precinct))  
    choices <- c('All', choices)
    selectInput(inputId = "precinct", label = "Precinct", choices = choices, selected = "CBD")

  })


  output$treedat <- renderLeaflet({
    #if(is.null(td)) return()
    ## get …

我想在传单地图上显示加拿大的多边形.

# create map
library(leaflet)
m = leaflet() %>% addTiles()
m

我能够找到加拿大的多边形:http://www.gadm.org/country.我为R选择了SpatialPolygonsDataFrame格式,但还有其他格式可用(例如Shapefile)

# load object in R
load("country_polygons/CAN_adm0.RData")
pol_can <- gadm

如何在地图上显示形状？我假设我必须利用sp包,但我无法弄清楚如何这样做.非常感谢您的帮助!