R Shiny中能否使用selectizeGroupUI筛选sf简单要素对象？

问题原因 #

你遇到的报错确实是shinyWidgets::selectizeGroupServer的特性导致的：该模块为了实现双向关联过滤逻辑，会自动将输入的所有数据转换为data.table格式，完全丢失sf对象的类属性和空间元信息，因此leaflet的addPolylines无法识别普通data.frame类型的输入，触发类型不匹配报错。
另外你现有构造线串的代码存在两处错误：一是坐标顺序写反（sf要求x/经度在前，y/纬度在后），二是构造矩阵时误将终点纬度写为了终点经度，会导致路径绘制异常。

解决方案 #

只需要在调用过滤后的数据时，用sf::st_as_sf()将其重新转回sf对象即可，同时修正线串构造逻辑，修改后的完整可运行代码如下：

library(tidyverse)
library(sf)
library(shiny)
library(shinyWidgets)
library(leaflet)

# 生成含几何数据的表
geo_data <- structure(list(idx = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
                           start_lat = c(33.40693,33.64672, 33.57127, 33.42848, 33.54936, 33.53418, 33.60399, 33.49554,33.5056, 33.61696),
                           start_long = c(-112.0298, -111.9255, -112.049,-112.0998, -112.0912, -112.0911, -111.9273, -111.9687, -112.0563, -111.9866),
                           end_lat = c(33.40687, 33.64776, 33.57125, 33.42853,33.54893, 33.53488, 33.60401, 33.49647, 33.5056, 33.61654),
                           end_long = c(-112.0343,-111.9303, -112.0481, -112.0993, -112.0912, -112.0911, -111.931,-111.9711, -112.0541, -111.986)),
                      row.names = c(NA, -10L), spec = structure(list(cols = list(idx = structure(list(), class = c("collector_double","collector")),
                                                                                 start_lat = structure(list(), class = c("collector_double", "collector")),
                                                                                 start_long = structure(list(), class = c("collector_double", "collector")),
                                                                                 end_lat = structure(list(), class = c("collector_double", "collector")),
                                                                                 end_long = structure(list(), class = c("collector_double","collector"))),
                                                                     default = structure(list(), class = c("collector_guess","collector")), delim = ","),
                                                                class = "col_spec"),class = c("data.table","data.frame"))


geo_data<- setDT(geo_data)

# 修正线串构造逻辑：坐标顺序为经度在前、纬度在后，替换错误的end_long为end_lat
geo_data <- geo_data[
  , {
    geometry <- sf::st_linestring(x = matrix(c(start_long, start_lat, end_long, end_lat), ncol = 2, byrow = TRUE))
    geometry <- sf::st_sfc(geometry, crs = 4326) # 明确指定WGS84坐标系
    geometry <- sf::st_sf(geometry = geometry)
  }
  , by = idx
]



# 生成过滤用维度表，关联几何数据后转sf
table <- structure(list(idx = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
                        column1 = c("A", "A", "A", "B", "B", "B", "C", "C", "C", "C"),
                        column2 = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)), row.names = c(NA, -10L),
                   class = c("tbl_df","tbl", "data.frame")) %>%
  left_join(x = ., y = geo_data, by = "idx", keep = FALSE)


sf <- sf::st_as_sf(table)


# Shiny应用
ui <- fluidPage(
  fluidRow(
    column(
      width = 10, offset = 1,
      tags$h3("Filter data with selectize group"),
      panel(
        selectizeGroupUI(
          id = "my-filters",
          params = list(
            column1 = list(inputId = "column1", title = "column1:"),
            column2 = list(inputId = "column2", title = "column2:")
          )
        ), status = "primary"
      ),
      leafletOutput(outputId = "map")
    )
  )
)

server <- function(input, output, session) {
  
  res_mod <- callModule(
    module = selectizeGroupServer,
    id = "my-filters",
    data = sf,
    vars = c("column1", "column2"))
  
  
  
  output$map <- renderLeaflet({
    leaflet() %>%
      addTiles() %>% # 增加默认底图，可根据需要替换
      addPolylines(data = st_as_sf(res_mod())) # 将过滤后的数据重新转为sf对象
  })
  
}

shinyApp(ui, server)

内容的提问来源于stack exchange，提问作者Biased_Observer