Реализация пакета ForestTools в Shiny

Question

Я пытаюсь создать веб-приложение, используя блестящий R. Веб-приложение должно принимать два изображения, введенных пользователем, выполнять некоторые функции и отображать выходные данные для загрузки.

Я хотел бы реализовать функцию vwf и функцию mcws из пакета ForestTools для получения пространственных файлов, которые могут быть загружены пользователем. Это приложение будет работать на локальном компьютере.

Упомянутые здесь DSM и DEM - это модель Digital Surface и Digital Elevation.

Вот код, который я реализовал в R.

library(raster)
library(ForestTools)

#data input
dsm<- raster("dsm.img")
dem<- raster("dem.img")

#canopy height model generation
chm<- dsm - dem   
plot(chm)

lin <- function(x){x * 0.05 + 0.6}  #linear function to define the window size

#variable window filter function to define treetops (predefined)

ttops <- vwf(CHM = chm, winFun = lin, minHeight = 3)  
summary(ttops) #Chech the minimum, mean and maximum tree height 
plot(ttops)

#raster format for delineating crown area.
crwn_poly<- mcws(treetops = ttops, CHM = chm, format = "polygons", minHeight = 1.5, verbose = FALSE) #vector polygons for crown boundaries.

#Specify the path for the file location (could be any local folder)
writeOGR(crownsPoly, dsn = "specify path", layer = 'poly', driver = "ESRI Shapefile") 

writeOGR(ttops, dsn = "ttops", layer = 'point', driver = "ESRI Shapefile")

Shiny R код:

library(shiny)
library(ForestTools)

ui<- fluidPage(
  sidebarPanel(
    #Adding two input image files for DSM and DEM
    fileInput(inputId = "file1", 
              label = "Upload DSM",
              accept = c('image/png', 'image/jpeg','image/jpg', 'image/tif')   #Input image 1 DSM
    ),
    fileInput(inputId = "file2", 
              label = "Upload DEM",
              accept = c('image/png', 'image/jpeg','image/jpg')   #input image 2 DEM
    ),
    #Input value for minumum height to delineate the trees
    numericInput("Tree_Ht", "Minimum Treetop height:",3, min = 1, max = 20 ),   #minimum tree height set by the user
    actionButton(inputId = "Input_action", label = "Submit")                    #submit button to start processing

    #a download function is also needed to download these shapefiles. Need to work on it as well. 
    #I am looking through it. But you can add in your input as well.
  ),

  #Two output files preferably a plot of Tree height and Crown width
  #Third output CHM generation
  mainPanel( 
    plotOutput("Plot1"), #CHM
    plotOutput("Plot2"), #Tree height
    plotOutput("Plot3") #Crown polygons
  )
)

subs<- function(x1,x2){x1-x2}    #Functoin for subtracting DSM and DEM 
lin <- function(x){x * 0.05 + 0.6}      #function for treetops 

server <- function(input, output,session){
  observeEvent(input$file1, {
    DSM<- input$file1
    if (is.null(DSM))
      return()
    file.copy(DSM$datapath, file.path("c:/temp", DSM$name) )
  })
  observeEvent(input$file2, {
    DEM<- input$file2
    if (is.null(DEM))
      return()
    file.copy(DEM$datapath, file.path("c:/temp", DEM$name) )
  })

 library(raster)
 library(ForestTools)

  #Generate CHM   
  chm<- eventReactive(input$input_action{ 
    subs(DSM,DEM)
  })

  output$Plot1<-renderPlot({  #Plot 1 CHM
    plot(chm)
  })

  #Treetops marking function using variable window filter (VWF)
  trtops<- eventReactive({
    ttops <- vwf(CHM = chm, winFun = lin, minHeight = 2)

  })
  output$Plot2<-renderPlot({                                         #plot 2 Treetops
    plot(chm, xlab = "", ylab = "", xaxt='n', yaxt = 'n')
    plot(ttops, col = "blue", pch = 20, cex = 0.5, add = TRUE)
  })
  crown<- eventReactive({
    cwns <- mcws(treetops = ttops, CHM = chm, minHeight = input$Tree_Ht , verbose = FALSE)
  })

  output$Plot3<-renderPlot({                                        #plot 3 Crown map
    plot(chm, xlab = "", ylab = "", xaxt='n', yaxt = 'n')
    plot(cwns, col = "blue", pch = 20, cex = 0.5, add = TRUE)
  })
}

shinyApp(server = server, ui = ui)