我制作了一个闪亮的应用程序，它使用 ggmap 将静态地图带回来。但是，当我想覆盖邮政编码边界时，我遇到了 ggplot 找不到数据集的错误。
数据集 poa 是邮政编码边界的数据框，即具有多边形 ID 的纬度和经度。我已经尝试添加environment = environment()，但这并不能解决我的问题。我知道数据存在，因为我调用print(str(poa))它打印到 R 控制台。
谁能为我建议一个解决方法，以便 ggplot 可以访问 poa 数据框？很抱歉，这不是一个可重复的例子。
更新：当我使用此代码时，ggplot 能够访问 poa 数据框：
print(ggmap(map)) + geom_polygon(data = poa, aes(x = LON, y = LAT, group = order), alpha = .5, colour = "black", fill = NA))
但是我需要为地图的基础层对 ggplot 进行嵌套调用，当我这样做时，ggplot 无法找到数据
这是我的 server.R 代码
我正在使用隔离，因为我的 ui.R 中有一个操作按钮，我只希望在单击它时更新绘图。
library(shiny)
library(ggmap)
library(RODBC)
# Define server logic required to summarize and view the selected dataset
shinyServer(function(input, output) {
output$searchString <- renderText({
if (input$searchButton == 0)
return()
isolate({input$searchString})
})
mapSourceInput <- reactive({
switch(input$mapSource
, "google" = "google"
, "stamen" = "stamen")
})
mapTypeInput <- reactive({
switch(input$mapType
, "terrain" = "terrain"
, "satellite" = "satellite"
, "roadmap" = "roadmap"
, "hybrid" = "hybrid"
, "toner" = "toner"
, "watercolor" = "watercolor")
})
overlayInput <- reactive({
switch(input$overlay
, "postcodes" = "postcodes"
, "states" = "states"
, "nothing" = "nothing")
})
output$map <- renderPlot({
if (input$searchButton == 0)
return()
isolate({
if (overlayInput() == "nothing"){
map <- get_map(location = input$searchString, zoom = input$zoom, source = mapSourceInput(), maptype = mapTypeInput())
mapPlot <- ggmap(map)
print(mapPlot)
#return()
} else {
if (overlayInput() == "postcodes"){
#postcode boundaries
map <- get_map(location = input$searchString, zoom = input$zoom, source = mapSourceInput(), maptype = mapTypeInput())
poa <- structure(list(POAOBS = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L)
, COORD_REF = 1:10
, COORD_POL = 1:10
, POLYGON = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L)
, LON = c(144.951431274414, 144.956451416016, 144.95539855957, 144.955993652344, 144.958465576172, 144.956634521484, 144.956817626953, 144.954727172852, 144.957550048828, 144.958831787109)
, LAT = c(-37.8131675720215, -37.8117561340332, -37.8094863891602, -37.8058776855469, -37.8061485290527, -37.8021659851074, -37.8010902404785, -37.7994079589844, -37.7997169494629, -37.799861907959)
, POA = c("3000", "3000", "3000", "3000", "3000", "3000", "3000", "3000", "3000", "3000"))
, .Names = c("POAOBS", "COORD_REF", "COORD_POL", "POLYGON", "LON", "LAT", "POA")
, row.names = c(NA, 10L)
, class = "data.frame")
print(str(poa))
print(ggmap(map, base_layer = ggplot(data = poa, aes(x = LON, y = LAT), environment = environment()), extent = "normal", maprange = FALSE, environment = .GlobalEnv) +
geom_polygon(data = poa, aes(x = LON, y = LAT, group = order), alpha = .5, colour = "black", fill = NA) +
coord_map(projection = "mercator",
xlim = c(attr(map, "bb")$ll.lon, attr(map, "bb")$ur.lon),
ylim = c(attr(map, "bb")$ll.lat, attr(map, "bb")$ur.lat)))
} else {
if(overlayInput() == "states"){
return()
}}}
})
})
})
编辑：添加 ui.R
library(shiny)
# Define UI for dataset viewer application
shinyUI(pageWithSidebar(
# Application title.
headerPanel("The New Map App"),
# Sidebar with controls
sidebarPanel(
textInput("searchString", "Get Map Of", value = "melbourne, australia")
, selectInput("mapSource", "Choose a Map Source", choices = c("google", "stamen"))
, numericInput("zoom", "Zoom Level", 10)
, helpText("Note: An integer from 3 (continent) to 21 (building), default value 10 (city)")
, selectInput("mapType", "Choose a Map Type", choices = c("terrain", "satellite", "roadmap", "hybrid", "toner", "watercolor"))
, helpText("Note: Options available are 'terrain', 'satellite', 'roadmap', and 'hybrid' (google maps), 'watercolor', and 'toner' (stamen maps)")
, radioButtons("overlay", "Overlay Polygon",
list("Postcodes" = "postcodes"
, "States" = "states"
, "Nothing" = "nothing"))
, actionButton("searchButton", "Get Map")
, tags$style(type='text/css', "button#searchButton { margin-bottom: 9px; }")
),
#output panel
mainPanel(
h3(textOutput("searchString"))
, plotOutput("map")
)
))
sessionInfo 的输出：
R version 3.0.1 (2013-05-16)
Platform: x86_64-pc-linux-gnu (64-bit)
locale:
[1] LC_CTYPE=en_AU.UTF-8 LC_NUMERIC=C LC_TIME=en_AU.UTF-8 LC_COLLATE=en_AU.UTF-8 LC_MONETARY=en_AU.UTF-8
[6] LC_MESSAGES=en_AU.UTF-8 LC_PAPER=C LC_NAME=C LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_AU.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] RODBC_1.3-7 ggmap_2.3 ggplot2_0.9.3.1 shiny_0.6.0
loaded via a namespace (and not attached):
[1] bitops_1.0-5 caTools_1.14 colorspace_1.2-2 dichromat_2.0-0 digest_0.6.3 grid_3.0.1
[7] gtable_0.1.2 httpuv_1.0.6.3 labeling_0.1 mapproj_1.2-1 maps_2.3-2 MASS_7.3-26
[13] munsell_0.4 plyr_1.8 png_0.1-5 proto_0.3-10 RColorBrewer_1.0-5 Rcpp_0.10.4
[19] reshape2_1.2.2 RgoogleMaps_1.2.0.3 rjson_0.2.12 RJSONIO_1.0-3 scales_0.2.3 stringr_0.6.2
[25] tools_3.0.1 xtable_1.7-1