在图层中使用继承 = FALSE 绘制地图

Question

我正在使用

plotly

创建一个带有颜色编码和动画点的地图以及一个

sf

对象。这些点本身就很好绘制。

sf

对象也可以很好地绘制。当我尝试使用

sf

选项将动画颜色编码与

inherit = FALSE

对象组合时，背景图不再绘制。我究竟做错了什么？任何帮助将不胜感激！

玩具示例：

library(sf)
library(dplyr)
library(plotly)

nc <- st_read(system.file("shape/nc.shp", package="sf")) %>%
      select(AREA) %>%
       sf::st_cast("MULTILINESTRING") %>%
       sf::st_cast("LINESTRING")
df <- expand.grid(x = seq(-76, -84, -2), y = seq(34, 36, 0.5)) %>%
      mutate(Group = sample(c("a", "b"), n(), replace = TRUE))

# plots points correctly, the animation works
plot_ly(df, lat = ~y, lon = ~x, color = ~Group, frame = ~Group,
    type = "scattermapbox", mode = 'markers') %>%
  layout(mapbox= list(style ="stamen-terrain", zoom = 4,
      center = list(lon = -80 ,lat= 35)))


# color-coding and animation work, and the sf object shows, but the map is gone
plot_ly() %>%
  add_markers(data = df, y = ~y, x = ~x, color = ~Group, frame = ~Group,
    type = "scattermapbox", mode = 'markers') %>%
  add_sf(data = nc, x = ~x, y = ~y, inherit = FALSE) %>%
  layout(mapbox= list(style ="stamen-terrain", zoom = 4,
      center = list(lon = -80 ,lat= 35)))

Answer 1

您可以将 df 转换为 sf 对象并使用 sf 对象的 CRS。在plot_ly调用中，您不必定义经/纬度或x/y坐标，因为坐标取自sf几何列。这是你的代码：

library(sf)
library(dplyr)
library(plotly)

nc <- st_read(system.file("shape/nc.shp", package="sf")) %>%
  select(AREA) %>%
  sf::st_cast("MULTILINESTRING") %>%
  sf::st_cast("LINESTRING")

head(nc)

# check crs
st_crs(nc)

df <- expand.grid(x = seq(-76, -84, -2), y = seq(34, 36, 0.5)) %>%
  mutate(Group = sample(c("a", "b"), n(), replace = TRUE))

# convert df to sf object and set crs
df <- st_as_sf(df, coords = c("x", "y"), crs = 4267)
head(df)

# color-coding and animation work, and the sf object shows, but the map is gone -> now it works
plot_ly() %>%
  add_sf(data = df, 
              color = ~Group, 
              frame = ~Group,
              type = "scattermapbox", 
              mode = 'markers') %>%
  add_sf(data = nc, 
         type = "scattermapbox", 
         mode = 'lines',
         inherit = FALSE) %>%
  layout(mapbox= list(style ="open-street-map", 
                      zoom = 4,
                      center = list(lon = -80 ,lat= 35)))

plot_ly