R Plotly地图多边形中心hover无提示框，仅边缘显示问题求助

1. 改用Plotly原生SF支持（推荐） #

直接用Plotly处理SF对象，跳过ggplot转换环节，能更精准控制多边形的hover交互范围，确保整个区域都能触发提示框：

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

# 读取并预处理数据
map_sf = read_sf("map.shp") %>%
  mutate(across(c("Frecuency", "Im", "Fo", "April", "July"), ~ifelse(is.na(.), 0, .)))

# 构建交互式地图
g_mapa_int = plot_ly(map_sf) %>%
  add_sf(
    fill = ~Frecuency,
    text = ~paste("Dp: ", NAME, "<br>",
                  "Frecuency: ", Frecuency, "<br>",
                  "I: ", Im, "<br>",
                  "F: ", Fo, "<br>",
                  "Abril: ", April, "<br>",
                  "Julio: ", July),
    hoverinfo = "text",
    colors = colorRamp(c("white", "darkblue"))
  ) %>%
  layout(
    title = "Title",
    legend = list(title = list(text = "Scale"))
  ) %>%
  config(displayModeBar = FALSE, showLink = FALSE)

# 显示地图
g_mapa_int

2. 为多边形添加不可见中心点标记 #

计算每个多边形的质心，添加透明/零尺寸的点标记，让中心区域也能触发提示框：

library(ggplot2)
library(plotly)
library(sf)
library(dplyr)

map = read_sf("map.shp") %>%
  mutate(across(c("Frecuency", "Im", "Fo", "April", "July"), ~ifelse(is.na(.), 0, .))) %>%
  # 计算质心坐标
  mutate(centroid = st_centroid(geometry)) %>%
  st_coordinates(centroid) %>%
  as.data.frame() %>%
  rename(lon = X, lat = Y) %>%
  bind_cols(map, .)

g_map = map %>%
  ggplot(aes(fill = Frecuency)) +
  geom_sf(aes(text = paste("Dp: ", NAME, "<br>",
                           "Frecuency: ", Frecuency, "<br>",
                           "I: ", Im, "<br>",
                           "F: ", Fo, "<br>",
                           "Abril: ", April, "<br>",
                           "Julio: ", July))) +
  # 添加不可见的质心点
  geom_point(aes(x = lon, y = lat, text = text), size = 0, alpha = 0) +
  scale_fill_gradient(low = "white", high = "darkblue") +
  labs(fill = "Scale", title = "Title") +
  theme_void()

g_mapa_int = ggplotly(g_map, tooltip = "text") %>%
  config(displayModeBar = FALSE, showLink = FALSE)

g_mapa_int

3. 修改ggplotly生成的Trace交互属性 #

如果坚持使用ggplot转换，可手动调整Plotly Trace的hoveron参数，让填充区域也能触发提示：

g_mapa_int = ggplotly(g_map, tooltip = "text") %>%
  config(displayModeBar = FALSE, showLink = FALSE) %>%
  # 设置hover触发范围为填充区域+线条
  style(hoveron = "fills+lines", traces = 1)

g_mapa_int

注：原代码存在变量名不一致问题（读取SF对象到maa但后续用map），需确保变量名统一。

内容的提问来源于stack exchange，提问作者Rodrigo