Question

我有一个小的Shiny应用程序 - 代码如下。这个想法是用户能够编辑，添加和删除点和多边形。因为最终产品将是两个shapefile（一个点，一个多边形），我需要将数据分开（并且很可能它们将具有不同的属性，因此将它们组合到一个数据集中不是选项）。

我的解决方案是每次都会生成mapview，具体取决于用户选择编辑的内容。我很高兴这很好用 - 但每次发生这种情况时，地图视图的范围都会重置为数据范围。我想找到一些方法来在更新之前捕获当前范围，以便我可以在setView中使用它来保持相同的范围。有没有办法做到这一点？ Mapview似乎没有这个功能，我不确定我怎么可能与Leaflet谈谈从这一点实现它。

任何帮助表示感谢。

应用：

library(shiny)
library(leaflet)
library(RColorBrewer)
library(rgdal)
library(leaflet.extras)
library(mapedit)
library(mapview)
library(sp)

workSpace <- "C:/temp"
myPoints <<- readOGR(workSpace,"Points")
myPolys <<- readOGR(workSpace,"Polys")

## Remove a few unneccesary attributes (for this exercise, anyway):
myPolys$Shape_Leng <- NULL
myPolys$Shape_Area <- NULL
myPoints$Shape_Leng <- NULL
myPoints$Shape_Area <- NULL
myPolys$OBJECTID <- NULL
myPoints$OBJECTID <- NULL

ui <- bootstrapPage(
  tags$style(type= "text/css", "html, body {width:100%;height:100%}"),
  editModUI("test-edit", height = "100%"),
  absolutePanel(top=10, right=10,width=300,
                wellPanel(style = "opacity: 0.80",
                          fluidRow(
                            tags$div(title = "Title",
                                   tags$h4("Select Edit Layer")
                            )
                          ),
                          fluidRow(
                            radioButtons(inputId = "layerChoice", label = NULL, choices = list("Polys" = 1, "Points" = 2))
                          )
                )
  )
)

server <-  function(input, output, session) {
  cntr_coords <- c(mean(coordinates(myPolys)[,1]), mean(coordinates(myPolys)[,2]))
  myMap <<- (mapview(myPolys) + mapview(myPoints))@map %>% setView(cntr_coords[1], cntr_coords[2], zoom = 17)
  result <- callModule(editMod, "test-edit", myMap, "myPolys")

  observeEvent(input$layerChoice, {
    if (input$layerChoice == 1)
    {
      result <- callModule(editMod, "test-edit", myMap, "myPolys")
    }
    else
    {
      result <- callModule(editMod, "test-edit", myMap, "myPoints")
    }
  })

  observe({req(result()$finished)
    ## Code here to save edits
    showModal(modalDialog(title = "Confirm save", 
                          "Do you want to save your edit?",
                          footer = tagList(
                            modalButton("Cancel"),
                            actionButton("ok", "OK")
                          )))
  })

  observeEvent(input$ok, {
    ## Write the data to the existing data
    ## firstly get the result.
    newData <- result()$finished
    if (input$layerChoice == 1) {

      ## Coerce into spatial data frame
      newPoly <- as(newData, "Spatial")
      ## Add required columns and give them a value (this will become a menu)
      newPoly$NAME <- "NewName"
      newPoly$CODE <- "CodeNEW"
      newPoly$Attrib1 <- "New Attrib"
      newPoly$Attrib2 <- 8888

      ## Drop the attributes we don't want
      newPoly$X_leaflet_id <- NULL
      newPoly$feature_type <- NULL

      ## Now merge with the existing data
      myPolys <<- rbind(myPolys, newPoly)
    }
    else
    {
      newPoint <- as(newData, "Spatial")
      ## Add required columns etc
      newPoint$NAME <- "NewPointName"
      newPoint$CODE <- "CodePt"

      ## Drop the attributes we don't want
      newPoint$X_leaflet_id <- NULL
      newPoint$feature_type <- NULL

      ## Now merge with the existing data
      myPoints <<- rbind(myPoints, newPoint)
    }
    ## Refresh the map
    myMap <<- (mapview(myPolys) + mapview(myPoints))@map
    ## Close the menu
    removeModal()
  })
}

# Run the application 
shinyApp(ui = ui, server = server)

我的数据文件在这里但很容易复制：

Points Polys

获取mapview的当前范围（R，in Shiny）

0 个答案: