当tmap正常工作时，如何解决ggplot中缺少的变量问题？

I have a large spatial data frame, head information here: class : SpatialPolygonsDataFrame features : 6 extent : 1268821, 1610480, 4828587, 5485976 (xmin, xmax, ymin, ymax) crs : +proj=tmerc +lat_0=0 +lon_0=173 +k=0.9996 +x_0=16000...