Estoy creando una aplicación simple Shiny + Leaflet R para navegar por un mapa sobre el cualraster (del paqueteraster) se traza con lo útiladdRasterImage() función. El código se basa en gran medida en los propios ejemplos de Leaflet. Sin embargo, me encuentro con algunos problemas con las capas: la imagen de trama se representa de alguna manera debajo de los mosaicos cada vez que recargo los mosaicos, incluso si establezco un negativozIndex. Esto no sucede para los marcadores. Ver el código adjunto. Archivo de entrada de ejemploaquí366 KB.

####
###### YOU CAN SKIP THIS, THE PROBLEM LIES BELOW ######
####

library(shiny)
library(leaflet)
library(RColorBrewer)
library(raster)

selrange <- function(r, min, max) {  #Very fast way of selecting raster range, even faster than clamp.
#http://stackoverflow.com/questions/34064738/fastest-way-to-select-a-valid-range-for-raster-data
  rr <- r[]
  rr[rr < min | rr > max] <- NA
  r[] <- rr
  r
}

llflood <- raster("example_flooding_posmall.nc")
ext <- extent(llflood)
flood <- projectRasterForLeaflet(llflood)
floodmin <- cellStats(flood, min)
floodmax <- cellStats(flood, max)

tiles <- c("Hydda.Base",
       "Hydda.Full",
       "Esri.WorldImagery",
       "Esri.WorldTopoMap"
)

ui <- bootstrapPage(
  tags$style(type = "text/css", "html, body {width:100%;height:100%}"),
  leafletOutput("map", width = "100%", height = "100%"),
  absolutePanel(top = 10, right = 10,
    sliderInput("range", "Return Period (years)", floor(floodmin), ceiling(floodmax),
      value = c(floor(floodmin), ceiling(floodmax)), step = 1
    ),
    selectInput("colors", "Color Scheme",
      rownames(subset(brewer.pal.info, category %in% c("seq", "div")))
    ),
    selectInput("tiles", "Background",
      tiles
    ),
    checkboxInput("legend", "Show legend", TRUE))
)

server <- function(input, output, session) {

  # Reactive expression for the data subsetted to what the user selected
  filteredData <- reactive({
    selrange(flood, input$range[1], input$range[2])
  })

  # This reactive expression represents the palette function,
  # which changes as the user makes selections in UI.
  colorpal <- reactive({
    colorNumeric(input$colors, values(filteredData()), na.color = NA)
  })

  ######
  ###### THE INTERESTING PART IS HERE ######
  ######

  output$map <- renderLeaflet({
    # Use leaflet() here, and only include aspects of the map that
    # won't need to change dynamically (at least, not unless the
    # entire map is being torn down and recreated).
    leaflet()  %>%
      fitBounds(ext[1], ext[3], ext[2], ext[4])
  })

  observe({ #Observer to edit tiles
    selectedTiles <- input$tiles
    leafletProxy("map") %>%
      clearTiles() %>%
      addProviderTiles(selectedTiles, providerTileOptions(zIndex=-10, continuousWorld=FALSE), group="base")
  })

  observe({ #Observer to edit colors and valid range
    filtdata <- filteredData()
    pal <- colorpal()
    leafletProxy("map") %>%
      clearImages() %>%
      addRasterImage(filtdata, opacity=0.7, project=FALSE, colors=pal, group="overlay") %>%
      addMarkers(lng=8.380508, lat=45.18058, popup="This marker stays above, the raster sinks below every time I load a new tile set")
  })

  ######
  ###### THE INTERESTING PART ENDS HERE ######
  ######

  observe({ #Observer to show or hide the legend
    inputlegend <- input$legend
    proxy <- leafletProxy("map")
    # Remove any existing legend, and only if the legend is
    # enabled, create a new one.
    proxy %>% clearControls()
    if (inputlegend) {
      pal <- colorpal()
      proxy %>% addLegend(position = "bottomright",
        pal = pal, values = values(filteredData()), opacity=1
      )
    }
  })

  cat("Clicked point:\tLon\t\tLat\t\tValue\n")
  observe({ #Observe to show clicked points
    x = as.double(unlist(input$map_click)[2])
    if(!is.null(x)) {
      y = unlist(input$map_click)[1]
      val = extract(llflood, cellFromXY(llflood, c(x, y)))
      if (!is.na(val)) cat("\t\t", x, "\t", y, "\t", val, "\n")
    }
  })

}

## RUN:
shinyApp(ui, server)