我有一个闪亮的应用程序,有大量的行
我想仅在缩放15处查看它并仅加载可见部分
library(leaflet)
library(shiny)
library(dplyr)
library(sf)
#random multilinestring
polyline_test <-st_multilinestring()
ui <- fluidPage(
leafletOutput("map")
)
server <- function(input, output, session){
output$map <- renderLeaflet({
leaflet() %>%
addTiles()
})
##Only select data visible on the map
new_zoom <- reactive({
if(!is.null(input$map_zoom)){
new_zoom <- input$map_zoom
}
else {new_zoom <- 2}
})
polyline_visible <- reactive({
validate(
need(new_zoom()>15,"t")
)
#bbox_zone <- input$map_bounds
#st_polygon()
#polyline_test
#What is the best way to extract the lines within the bounds ?
})
#Show layer only at zoom 15
observe({
if (new_zoom() > 15) {
leafletProxy("map") %>%
addPolylines(data = polyline_visible())
}else{
leafletProxy("map") %>% clearShapes()
}
})
}
shinyApp(ui = ui, server = server)
我想知道在可见地图范围内提取线条的最佳方法吗?