在R传单交互式地图中，我的所有值都显示不正确（而数据框中的值都是正确的）

Question

出于某种原因，尽管数据框中的叙利亚的值 = 1，但当我绘制地图时，它显示为 0.038，并被称为白俄罗斯……所有其他国家也得到了一些疯狂的值和其他国家/地区名称。我不明白为什么会这样。这是代码...

#libraries
library(tidyverse)
library(leaflet)
library(rnaturalearth)
library(rnaturalearthdata)
library(sf)
library(countrycode)

#load world data from natural earth
world <- ne_countries(scale = "large", returnclass = "sf")
world <- st_transform(world, "+proj=longlat +datum=WGS84")

countrynames <- countryname_dict %>% 
  group_by(country.name.en) %>% 
  summarise(country.name.en) %>% 
  distinct()

countrynames <- dplyr::pull(countrynames, country.name.en)

# These values are random just to test out mapping. I wanted for each country to have a color based on the ratio between 0 and 1 with some random numbers. All of them ARE indeed between 0 and 1 in the data frame
world_values <- c(1:284)
df <- cbind (countrynames, world_values)
df <- as.data.frame(df)
df$world_values <- as.numeric(df$world_values)
df$world_values[241] <- 599
df <- df %>% 
  mutate(Value = world_values / 599)

# Match country codes in world data with countrynames
df$iso_a3 <- countrycode(sourcevar = countrynames, origin = "country.name", destination = "iso3c")
df <- df %>% na.omit()

map <- leaflet() %>%
  addProviderTiles("Esri.WorldGrayCanvas") %>%
  setView(lng = 0, lat = 0, zoom = 2)

palette <- colorNumeric(
  palette = "Blues",
  domain = c(0,1)
)

# Add country polygons layer
map <- map %>% 
  addPolygons(
    data = world,
    stroke = TRUE,
    fillColor = ~palette(df$Value),
    fillOpacity = 0.5,
    popup = ~paste("Country:", df$countrynames, "<br>", "Value:", df$Value),
    color = "white",
    weight = 1,
    layerId = ~iso_a3,
    label = NULL
  )

# Print the map
map

我尝试将layerId、fillColor、palette 和popup 更改为其他内容。我已经无计可施了。

Answer 1

您在

leaflet

中使用一个数据集用于多边形，另一个数据集用于属性数据。我想如果

world

和

df

中的行数和国家/地区顺序都匹配，则这种方法会起作用，但目前

world

中的前 3 个是 “印度尼西亚”、“马来西亚”、“智利”，而在

 df

顶部写着 “阿富汗”、“奥兰群岛”、“阿尔巴尼亚”。

如果您尝试使这两者匹配，它仍然非常脆弱并且难以调试，因此在大多数情况下您希望将属性表连接到空间数据集并将其与映射库一起使用。这也是

leaflet

中公式 (~) 表示法的基础，其中

data = world, fillColor = ~ palette(Value)

的意思是：
使用

Value

data.frame 中的

world

列来计算

fillColor

library(dplyr)
library(leaflet)
library(rnaturalearth)
library(sf)
library(countrycode)

# sf object with just counrty polygons and A3 codes
world_sf <- ne_countries(scale = "large", returnclass = "sf") %>% 
  # tibble printing is more compact
  as_tibble() %>% 
  st_as_sf() %>% 
  select(adm0_a3)
world_sf 
#> Simple feature collection with 258 features and 1 field
#> Geometry type: MULTIPOLYGON
#> Dimension:     XY
#> Bounding box:  xmin: -180 ymin: -90 xmax: 180 ymax: 83.6341
#> Geodetic CRS:  WGS 84
#> # A tibble: 258 × 2
#>    adm0_a3                                                              geometry
#>    <chr>                                                      <MULTIPOLYGON [°]>
#>  1 IDN     (((117.7036 4.163415, 117.7036 4.163415, 117.7381 4.157242, 117.7836…
#>  2 MYS     (((117.7036 4.163415, 117.6971 4.169053, 117.6441 4.215237, 117.6401…
#>  3 CHL     (((-69.51009 -17.50659, -69.50611 -17.58513, -69.49712 -17.6214, -69…
# ...  

# 2nd dataset, only atributes
df_ <- distinct(countryname_dict, countrynames = country.name.en) %>% 
  as_tibble() %>% 
  mutate(world_values = row_number() / 599,
         world_values = if_else(countrynames == "Syria", 1, world_values),
         # world_values = replace(world_values, 241, 1),
         iso_a3 = countrycode(countrynames, "country.name", "iso3c")) %>% 
  na.omit()
df_
#> # A tibble: 247 × 3
#>    countrynames      world_values iso_a3
#>    <chr>                    <dbl> <chr> 
#>  1 Afghanistan            0.00167 AFG   
#>  2 Åland Islands          0.00334 ALA   
#>  3 Albania                0.00501 ALB   
# ...

# join datasets by world_sf$adm0_a3 == df_$iso_a3, inner join keerp only records 
# that are present in both datasets
leaflet_sf <- inner_join(world_sf, df_, by = join_by(adm0_a3 == iso_a3)) 
leaflet_sf
#> Simple feature collection with 232 features and 3 fields
#> Geometry type: MULTIPOLYGON
#> Dimension:     XY
#> Bounding box:  xmin: -180 ymin: -90 xmax: 180 ymax: 83.6341
#> Geodetic CRS:  WGS 84
#> # A tibble: 232 × 4
#>    adm0_a3                                    geometry countrynames world_values
#>    <chr>                            <MULTIPOLYGON [°]> <chr>               <dbl>
#>  1 IDN     (((117.7036 4.163415, 117.7036 4.163415, 1… Indonesia          0.195 
#>  2 MYS     (((117.7036 4.163415, 117.6971 4.169053, 1… Malaysia           0.244 
#>  3 CHL     (((-69.51009 -17.50659, -69.50611 -17.5851… Chile              0.0835
# ...


palette <- colorNumeric(
  palette = "Blues",
  domain = c(0,1)
)

map_ <- leaflet() %>%
  addProviderTiles("Esri.WorldGrayCanvas") %>%
  setView(lng = 0, lat = 0, zoom = 2) %>% 
  addPolygons(
    data = leaflet_sf,
    stroke = TRUE,
    fillColor = ~ palette(world_values),
    fillOpacity = 0.5,
    popup = ~ paste("Country:", countrynames, "<br>", "Value:", world_values),
    color = "white",
    weight = 1,
    layerId = ~ adm0_a3,
    label = NULL
  )
map_

^{创建于 2023-06-06，使用 reprex v2.0.2}