我正在努力在一个Shiny应用程序中绘制多个多边形 - 基于传单包。
这是我希望的非应用输出:
data <- list(
beam1 = data.frame(lat = c(-115,-125, -125, -115),
lon = c(32, 32, 45,45)),
beam2 = data.frame(lat = c(-100, -111, -111, -100),
lon = c(42, 42, 50,50))
)
dataTemp <- do.call(rbind, lapply(data, function(x) rbind(x, NA)))
library(leaflet)
m = leaflet() %>% addTiles()
m %>%
addPolygons(
dataTemp[,"lat"],
dataTemp[,"lon"],
color = c('red', 'green'), weight = 3
)
然而,从中创建一个Shiny应用程序被证明是困难的 - 多边形被绘制然后在绘制新多边形后逐个消失。这是我正在使用的代码。你需要点击&#39; Draw&#39;绘制多边形 请注意: 1 - 绘制绿色时红色多边形消失(3秒后) 2 - 多边形在这里是三角形,而在上面的代码中它们是矩形。 3 - 如果你看下面server.R中的代码,我实际上不得不翻转&#39; lat&#39;和&#39; lon&#39;列甚至可以远程校正图片。
ui.R:
library(shiny)
library(leaflet)
shinyUI(navbarPage("Beams", id="nav",
tabPanel("Interactive map",
div(class="outer",
leafletMap("map", "100%", 650,
options = list(center = c(37.45, -93.85), zoom = 4)),
actionButton("drawPoints", "Draw")
)
)
))
server.R:
library(shiny)
library(leaflet)
data <- list(
beam1 = data.frame(lat = c(-115,-125, -125, -115),
lon = c(32, 32, 45,45)),
beam2 = data.frame(lat = c(-100, -111, -111, -100),
lon = c(42, 42, 50,50))
)
# server activity
shinyServer(function(input, output, session) {
map <- createLeafletMap(session, "map")
observe({
if(input$drawPoints == 0) {
return(NULL)
} else {
map$clearShapes()
for (i in seq_along(data)) {
map$addPolygon(
data[[i]][,"lon"], # - notice, i had to change lat and lon
data[[i]][,"lat"],
layerId=c("1"),
list( fillOpacity=0.4),
list(color = c('red','green')[i])
)
Sys.sleep(3) # - this is to see first (red) polygon
}
}
})
})
任何想法都将不胜感激!
答案 0 :(得分:0)
我已更新您的代码以使用传单代理,这是更新现有地图的一种更简洁的方法,并且是在leaflet
包的持续更新中执行此操作的当前维护方法(据我所知) )。我在data.frame中切换了“lat”和“lon”以使它们正确。我还在坐标的末尾再次添加了原点以完成形状 - 这就是为什么你有三角形而不是矩形的原因。最后,我将多边形的layerId
更改为i
以使它们不同 - 这就是它们相互擦除的原因。
我假设您希望对形状进行硬编码,但有多种方法可以向用户打开多边形图选择(甚至绘图)。有趣的说明:在解决此问题时,了解deferUntilFlush
中的leafletProxy
参数 - 如果设置为FALSE
,则只有在Sys.sleep
计数完成后才会绘制两个形状。
ui.R
library(shiny)
library(leaflet)
shinyUI(navbarPage("Beams", id="nav",
tabPanel("Interactive map",
div(class="outer",
leafletOutput("map", "100%", 650),
actionButton("drawPoints", "Draw")
)
)
))
server.R
library(shiny)
library(leaflet)
data <- list(
beam1 = data.frame(lon = c(-115,-125, -125, -115, -115),
lat = c(32, 32, 45, 45, 32)),
beam2 = data.frame(lon = c(-100, -111, -111, -100, -100),
lat = c(42, 42, 50, 50, 42))
)
shinyServer(function(input, output, session) {
map <- leaflet() %>% addTiles() %>% setView(-93.85, 37.45, zoom = 4)
output$map <- renderLeaflet(map)
proxy <- leafletProxy("map", deferUntilFlush = FALSE)
observeEvent(input$drawPoints, {
proxy %>% clearShapes()
for (i in seq_along(data)) {
proxy %>% addPolygons(
data[[i]][,"lon"],
data[[i]][,"lat"],
layerId=i,
opacity=0.4,
color = c('red','green')[i]
)
Sys.sleep(2) # - this is to see first (red) polygon
}
})
})