Geom Polygon在Quarters中切割我的GGMAP

Question

运行我的代码时，我的地图会被X剪切。我无法发布数据，但我可以发布代码。我试图在ggmap上使用Voronoi图，并在其上使用点。地图看起来不错，但是一半是voronoi，一半是地图。

sbbox <- make_bbox(lon = c( -98.70445,-98.31298), lat = c(29.35194,29.6695))
sq_map <- get_map(location = sbbox, maptype = "terrain", source = "google")

ggmap(sq_map)  + 
  geom_polygon(fill = 'grey') +
  geom_segment(data = deldir_ds,
               aes(x = y1, y = x1, xend = y2, yend = x2), 
               size = .50, linetype = 2, color = rgb(229/255, 229/255, 229/255)) +
  geom_point(data=newstores, 
             aes(x = newstores$LON_L, y = newstores$LAT_L)) +
  geom_point(data=newsa45, 
             aes(x = newsa45$LON_K, y = newsa45$LAT_K, colour = "red")) +
  scale_x_continuous(expand = c(0, 0)) +
  scale_y_continuous(expand = c(0, 0)) +
  theme(panel.grid = element_blank())