如何在闪亮的应用程序地图视图传单中可视化单点

Question

我有一个很大的数据集，但我提供了 3 条记录，以使这个示例可以用 最小数据量。我可以同时在传单上展示所有 3 个网站，但我想 也一次显示一条记录。我的问题是，我怎样才能在地图上显示一个站点 单击输入下拉菜单的时间。例如，如何仅显示 site2 而不是显示 所有 3 条记录？我知道“开关”，但不知道如何在这里实现它。 我下面有一些代码和可重现的数据。预先感谢您的任何建议。

  Location            geometry
* <chr>            <POINT [°]>
1 site1    (-115.1682 44.3943)
2 site2    (-114.0403 44.6845)
3 site3    (-114.8841 44.1533)

library(shiny)
library(mapview)
library(writexl)
library(tidyverse)
library(leaflet)

locations <- c("site1", "site2", "site3") 
 ui <- fluidPage(

#titlePanel("Screwtraps and temp logger in Idaho"),
sidebarLayout(
sidebarPanel(
selectInput(inputId = "site",
           label = "Select Site",
                   choices = locations)),
    mainPanel(leafletOutput("map",width = "100%", height="87vh") 
    )
   )
 )
 
 server <- function(input, output, session) {
  session$onSessionEnded(function() {
    stopApp()
  })
  
  output$map<-renderLeaflet({
 #Select all sites
    final <- mapview(site, col.regions='red', alpha=1) 
   final@map 
   #How can I render my map with only the selected site from the userInput dropdown?

    })
}

shinyApp(ui, server)


Data is here: 

site <- structure(list(Location = c("site1", "site2", "site3"), geometry = structure(list(
    structure(c(-115.1682, 44.3943), class = c("XY", "POINT", 
    "sfg")), structure(c(-114.0403, 44.6845), class = c("XY", 
    "POINT", "sfg")), structure(c(-114.8841, 44.1533), class = c("XY", 
    "POINT", "sfg"))), n_empty = 0L, precision = 0, crs = structure(list(
    input = "EPSG:4326", wkt = "GEOGCRS[\"WGS 84\",\n    DATUM[\"World Geodetic System 1984\",\n        ELLIPSOID[\"WGS 84\",6378137,298.257223563,\n            LENGTHUNIT[\"metre\",1]]],\n    PRIMEM[\"Greenwich\",0,\n        ANGLEUNIT[\"degree\",0.0174532925199433]],\n    CS[ellipsoidal,2],\n        AXIS[\"geodetic latitude (Lat)\",north,\n            ORDER[1],\n            ANGLEUNIT[\"degree\",0.0174532925199433]],\n        AXIS[\"geodetic longitude (Lon)\",east,\n            ORDER[2],\n            ANGLEUNIT[\"degree\",0.0174532925199433]],\n    USAGE[\n        SCOPE[\"Horizontal component of 3D system.\"],\n        AREA[\"World.\"],\n        BBOX[-90,-180,90,180]],\n    ID[\"EPSG\",4326]]"), class = "crs"), bbox = structure(c(xmin = -115.1682, 
ymin = 44.1533, xmax = -114.0403, ymax = 44.6845), class = "bbox"), class = c("sfc_POINT", 
"sfc"))), row.names = c(NA, 3L), sf_column = "geometry", agr = structure(c(Location = NA_integer_), class = "factor", .Label = c("constant", 
"aggregate", "identity")), class = c("sf", "tbl_df", "tbl", "data.frame"
))

site

Answer 1

如果您想选择一个站点、多个站点或所有站点，您可以使用shinyWidgets包中的

pickerInput

。要显示单个（或多个）站点，您只需对数据进行子集化即可。使用

pickerInput

，可以更轻松地选择一些或不选择。希望这对您有帮助。

library(shiny)
library(shinyWidgets)
library(mapview)
library(leaflet)

locations <- c("site1", "site2", "site3") 

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      pickerInput(inputId = "site",
                  label = "Select Site",
                  choices = locations,
                  selected = locations,
                  options = list(`actions-box` = TRUE),
                  multiple = TRUE)),
    mainPanel(leafletOutput("map",width = "100%", height="87vh") 
    )
  )
)

server <- function(input, output, session) {
  
  output$map<-renderLeaflet({
    req(input$site)
    final <- mapview(site[site$Location %in% input$site, ], 
                     col.regions = 'red',
                     layer.name = "Site",
                     alpha = 1) 
    final@map 
  })
  
}

shinyApp(ui, server)