多边形映射

在 R 中使用 leaflet 构建交互式地图

Rich Majerus

Vice President of Strategy & Planning, Queens University of Charlotte

绘制多边形

shp %>% 
  leaflet() %>% 
  addTiles() %>% 
  addPolygons()

所有北卡邮编 1

addPolygons()

weight：边界线像素厚度
color：多边形颜色
label：悬停时显示的信息
highlight：悬停高亮选项

shp %>% 
leaflet() %>% 
addTiles() %>% 
addPolygons(weight = 1,
            color = "grey",
            label = ~paste0("Total Income: " dollar(income)),
            highlight = highlightOptions(weight = 3, color = "red",
                                         bringToFront = TRUE))

addPolygons()

所有北卡邮编 2

数值数据着色

colorNumeric

nc_pal <- colorNumeric(palette = "Blues", 
                       domain = high_inc@data$mean_income)

colorBin

nc_pal <- colorBin(palette = "YlGn", bins = 5,
                   domain = high_inc@data$mean_income)

colorQuantile

nc_pal <- colorQuantile(palette = "YlGn", n = 4, 
                        domain = high_inc@data$mean_income)

colorNumeric()

nc_pal <- colorNumeric("Blues", domain = high_inc@data$mean_income)

previewColors(pal = nc_pal, 
              values = c(seq(100000, 600000, by = 100000)))

previewColors() 预览

分级着色图

nc_pal <- colorNumeric(palette = "Blues", 
                       domain = shp@data$mean_income)

shp %>% 
  leaflet() %>% 
  addTiles()  %>% 
  addPolygons(weight = 1, fillOpacity = 1,
              color =  ~nc_pal(mean_income),
              label = ~paste0("Mean Income: ", 
                              dollar(mean_income)),
              highlight = highlightOptions(weight = 3,
                                           color = "red",
                                           bringToFront = TRUE))

分级着色图

北卡收入分级着色图

分级着色示例

ggplot(shp@data,
       aes(mean_income)) +
  geom_histogram()

收入直方图

ggplot(shp@data, 
        aes(log(mean_income))) +
  geom_histogram()

取对数的收入直方图

取对数

北卡收入取对数分级着色图 1

Passons à la pratique !

在 R 中使用 leaflet 构建交互式地图