Update the geometry of an existing drawn shape on the map

Update the geometry of an existing drawn shape on the map

Usage

update_drawn_shape(proxy, shape_id, new_geometry)

Arguments

proxy

The map proxy object created by mapProxy().

shape_id

The ID of the shape to update.

new_geometry

The new geometry for the shape, provided as an sf object, GeoJSON string, or list that can be converted to GeoJSON.

Value

The map proxy object for chaining.

Examples

library(shiny)
library(dplyr)
library(sf)
library(toro)

get_polygon <- function() {
  random_offset <- runif(1, -10, 10)
  sf::st_sf(
    geometry = sf::st_sfc(
      sf::st_polygon(list(matrix(
        c(
          174.7,
          -36.8,
          174.8,
          -36.8,
          174.8,
          -36.9,
          174.7,
          -36.9,
          174.7,
          -36.8
        ) +
          random_offset,
        ncol = 2,
        byrow = TRUE
      ))),
      crs = 4326
    )
  )
}

ui <- bootstrapPage(
  tagList(
    mapOutput("map"),
    actionButton("add", "Add shape"),
    actionButton("update", "Update shape"),
    actionButton("delete", "Delete shape"),
    h2("Selected shape ID"),
    textOutput("selected_shape")
  )
)

server <- function(
  input,
  output,
  session
) {
  selected_shape_id <- reactiveVal(NULL)

  output$map <- renderMap({
    map() |>
      add_draw_control(
        modes = c("polygon", "line", "delete"),
        features = get_polygon()
      )
  })

  output$selected_shape <- renderText({
    selected_shape_id()
  })

  observe({
    print(input$map_feature_click)
    selected_shape_id(input$map_feature_click$properties$id)
  }) |>
    bindEvent(input$map_feature_click)

  observe({
    add_drawn_shape(mapProxy("map"), get_polygon())
    selected_shape_id(NULL)
  }) |>
    bindEvent(input$add)

  observe({
    req(selected_shape_id())
    update_drawn_shape(mapProxy("map"), selected_shape_id(), get_polygon())
  }) |>
    bindEvent(input$update)

  observe({
    req(selected_shape_id())
    delete_drawn_shape(mapProxy("map"), selected_shape_id())
    selected_shape_id(NULL)
  }) |>
    bindEvent(input$delete)
}

if (interactive()) {
  shinyApp(ui, server)
}