如何保存在R传单闪亮地图中绘制的addDrawToolbar形状，以便重新导入它们

Question

我需要使用leaflet.extras中的addDrawToolbar在R Leaflet Shiny应用程序中绘制形状，并将其保存到一个文件中，该文件稍后可以由R Leaflet闪亮应用程序重新导入。

我关注的是Bhaskar Karambelkar在GitHub中的leaflet.extras信息，其中列出了为绘制的形状提取数据的命令。如何解析R中的数据？

到目前为止，我可以执行以下代码：绘制形状并将其打印为.csv或.txt文件。我已经包括了这两个例子。因此，在这段代码中，您可以从绘图工具栏绘制您想要的任何形状，然后点击Generate Shape List按钮

它可以捕获所有形状坐标，但在这些格式中，数据并不像我需要的那样可用。有没有办法解析这些数据，以便在需要时可以重新导入、显示和编辑？对此有任何见解，我们将不胜感激！

library(shiny)
library(leaflet)
library(leaflet.extras)
library(utils)
sh <- data.frame()
ui <- bootstrapPage(
tags$style(type = "text/css", "html, body {width:100%;height:100%}"),
leafletOutput("mymap", width = "100%", height = "100%"),
absolutePanel(top = 10, right = 10, width = 300,
style = "padding: 8px",
actionButton("printShapes", h5(strong("Generate Shape List")))
)
)
server <- function(input, output, session) {

output$mymap <- renderLeaflet({
leaflet() %>%
addTiles(group = "Default", attribution = 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors') %>%
setView(lng = -98, lat = 38, zoom = 4) %>%
addDrawToolbar(targetGroup = "draw", position = "topleft", editOptions = editToolbarOptions(edit=TRUE))
})

# Generate Shape List Action Button
observeEvent(input$printShapes, {
shapedf <- data.frame()
reactive(shapedf)                       
shapedf <-input$mymap_draw_all_features  
sh <<- as.data.frame(shapedf)           
sh <- t(sh)                             
shpwrite <- write.csv(sh, paste0("OUTPUTdrawings",".csv"))
shpwrite1 <- dput(sh, file = "OUTPUTdrawings1.txt")
})
}
shinyApp(ui = ui, server = server)

Answer 1

经过深思熟虑、焦虑、反复尝试，我终于想出了如何做到这一点。不确定这是否是最好的方法，但它有效。

library(shiny)
library(leaflet)
library(leaflet.extras)
library(utils)
sh <- data.frame()
ui <- bootstrapPage(
tags$style(type = "text/css", "html, body {width:100%;height:100%}"),
leafletOutput("mymap", width = "100%", height = "100%"),
absolutePanel(top = 10, right = 10, width = 300,
style = "padding: 8px",
fileInput("drawingFile",h4(strong("Input Drawing CSV")), accept = ".csv"),
actionButton("printShapes", h5(strong("Generate Drawing File")))
)
)
server <- function(input, output, session) {

output$mymap <- renderLeaflet({
leaflet() %>%
addTiles(group = "Default", attribution = 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors') %>%
setView(lng = -98, lat = 30, zoom = 4) %>%
addDrawToolbar(targetGroup = "draw", position = "topleft", editOptions = editToolbarOptions(edit=TRUE))
})

# Generate Shape List Action Button
observeEvent(input$printShapes, {
shapedf <- data.frame()
reactive(shapedf)
shapedf <-input$mymap_draw_all_features
sh <<- as.data.frame(shapedf)

# sh <- t(sh) # This is easier to read manually, but not for reading into R.
shpwrite <- write.csv(sh,paste0("Drawings", ".csv"))
})

# Intake Shape CSV
observeEvent(input$drawingFile, {
drawFile <- input$drawingFile
ext <- file_ext(drawFile$datapath)
req(drawFile)
validate(need(ext == "csv", "Please upload a csv file."))

ddf <- read.csv(drawFile$datapath, header = TRUE) # The drawing dataframe
ind <- which(ddf == "Feature") # Index for drawing df to break up the df to redraw the shapes.
ind <- as.array(ind)

for (i in 1:nrow(ind)) {
if(i != nrow(ind)) thisShape <- ddf[ind[i]:ind[i+1]]
else thisShape <- ddf[ind[i]:ncol(ddf)]

#####
if(thisShape[3] == "polyline") {
tf <- array(startsWith(names(thisShape),"features.geometry.coordinates"))
w <- 1
pnts <- array()
for (i in 1:nrow(tf)) {
if(tf[i] == TRUE) {
pnts[w] <- thisShape[i]
w <- w+1
}
}
n <- 1
m <- 1
plng <- array()
plat <- array()
pnts <- as.array(pnts)
for (j in 1:nrow(pnts)) {
if(j %% 2 == 1) {
plng[n] <- pnts[j]
n <- n+1
}
else if(j %% 2 == 0) {
plat[m] <- pnts[j]
m <- m+1
}
}
as.vector(plng, mode = "any")
as.vector(plat, mode = "any")
PL <- data.frame(matrix(unlist(plng)))
PLsub <- data.frame(matrix(unlist(plat)))
PL <- cbind(PL, PLsub)
colnames(PL) <- c("lng","lat")
PL1 <- reactiveVal(PL)

proxy <- leafletProxy("mymap", data = PL1())
proxy %>% addPolylines(lng = ~lng, lat = ~lat, group = "draw")
}
#####
else if(thisShape[3] == "polygon") {
tf <- array(startsWith(names(thisShape),"features.geometry.coordinates"))
w <- 1
pnts <- array()
for (i in 1:nrow(tf)) {
if(tf[i] == TRUE) {
pnts[w] <- thisShape[i]
w <- w+1
}
}
n <- 1
m <- 1
plng <- array()
plat <- array()
pnts <- as.array(pnts)
for (j in 1:nrow(pnts)) {
if(j %% 2 == 1) {
plng[n] <- pnts[j]
n <- n+1
}
else if(j %% 2 == 0) {
plat[m] <- pnts[j]
m <- m+1
}
}
as.vector(plng, mode = "any")
as.vector(plat, mode = "any")
PG <- data.frame(matrix(unlist(plng)))
PGsub <- data.frame(matrix(unlist(plat)))
PG <- cbind(PG, PGsub)
colnames(PG) <- c("lng","lat")
PG1 <- reactiveVal(PG)

proxy <- leafletProxy("mymap", data = PG1())
proxy %>% addPolygons(lng = ~lng, lat = ~lat, group = "draw")
}
#####
else if(thisShape[3] == "rectangle"){
rlng1 <- as.numeric(thisShape[5])
rlat1 <- as.numeric(thisShape[6])
rlng2 <- as.numeric(thisShape[9])
rlat2 <- as.numeric(thisShape[10])

proxy <- leafletProxy("mymap")
proxy %>% addRectangles(lng1 = rlng1, lat1 = rlat1, lng2 = rlng2, lat2 = rlat2,
group = "draw")
}
#####
else if(thisShape[3] == "circle"){
crad <- as.numeric(thisShape[4])
clng <- as.numeric(thisShape[6])
clat <- as.numeric(thisShape[7])

proxy <- leafletProxy("mymap")
proxy %>% addCircles(lng = clng, lat = clat, radius = crad, group = "draw")
}
#####
else if(thisShape[3] == "marker") {
mlng <- as.numeric(thisShape[5])
mlat <- as.numeric(thisShape[6])

proxy <- leafletProxy("mymap")
proxy %>% addMarkers(lng = mlng, lat = mlat, group = "draw")
}
#####
else if(thisShape[3] == "circlemarker") {
cmlng <- as.numeric(thisShape[6])
cmlat <- as.numeric(thisShape[7])

proxy <- leafletProxy("mymap")
proxy %>% addCircleMarkers(lng = cmlng, lat = cmlat, group = "draw")
}
}
})
}
shinyApp(ui = ui, server = server)