浏览了 Shiny integration example on the Leaflet for R page ,我在子集化和显示一些多边形以在我的 Shiny 应用程序中显示时遇到问题。
目前,我正在获取一个带有侧边栏的应用程序,但主要显示只是“错误:不知道如何从 react 类对象获取路径数据”
这个想法是从 GB(3 个国家)中选择一个国家多边形并根据下拉选项单独显示它;
require(shiny)
require(rgdal)
require(rgeos)
require(leaflet)
cont <- readOGR(".\\mypath\\mypolygons.shp", "mypolygons", stringsAsFactors=FALSE)
ui <- fluidPage(
titlePanel("My page"),
sidebarLayout(
sidebarPanel(
selectInput("countryInput", "Country:", choices = c('England','Scotland','Wales'))
),
mainPanel(
leafletOutput("mymap")
)
)
)
server <- function(input, output, session) {
pols <- eventReactive(input$countryInput,{cont[substr(cont@data$code,1,1)==substr(input$countryInput,1,1),]})
output$mymap <- renderLeaflet({
leaflet() %>%
addProviderTiles("CartoDB.Positron") %>%
addPolygons(data = pols)
})
}
shinyApp(ui, server)
错误:
Warning: Error in polygonData.default: Don't know how to get path data from object of class reactive
Stack trace (innermost first):
83: polygonData.default
82: polygonData
81: derivePolygons
80: addPolygons
79: function_list[[k]]
78: withVisible
77: freduce
76: _fseq
75: eval
74: eval
73: withVisible
72: %>%
71: func [#6]
70: output$mymap
4: <Anonymous>
3: do.call
2: print.shiny.appobj
1: <Promise>
最佳答案
修复:
首先我改变了;
pols <- eventReactive(input$countryInput,{cont[substr(cont@data$code,1,1)==substr(input$countryInput,1,1),]})
到;
pols <- reactive({cont.sim[substr(cont.sim@data$gssCode,1,1)==substr(input$countryInput,1,1),]
并且“addPolygons”行在变量名称“pols”之后缺少开/闭括号
addPolygons(data = pols)
变成了
addPolygons(data = pols())
关于r - 传单/ Shiny : cannot draw reactive polygons,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40800962/