我正在尝试在ggplot2的地图中添加一些详细信息，但是我是该软件包的新手，因此不确定如何进行操作。代码和地图在下面（忽略地图上怪异的间距，我在Rstudio中进行了截屏）。感谢您的关注！

我正在尝试执行以下操作：

1. 在x和y轴上添加纬度和经度刻度线。我在下面的脚本中编写了代码，但是什么也没发生，不知道为什么-没有错误弹出。
2. 如果可能的话，我想在插图中添加一个框来显示较大地图的范围/覆盖范围，因为较小地图中的点（红色的点）几乎看不见。我不确定如何在插图中添加和放置多边形。

这是当前地图供参考的外观：

library(raster)
library(ggplot2)
library(ggthemes)
library(ggsn)
library(ggmap)
library(maps)
library(mapdata)

mapdata <- getData("GADM",country = "panama",level = 1)
mymap <- fortify(mapdata)

mypoint <- data.frame(long=c(-79.743,-79.696,-79.645,-79.595),lat=c(9.160,9.117,9.058,9.015),group=c("L","GW","OGR","LC"))
mypoint2 <- data.frame(long=c(-79.846,-79.707,-79.665,-79.610),lat=c(9.181,9.112,9.057,9.014),group=c("BCI","G","EH","MF"))

g1 <- ggplot() +
  geom_blank(data = mymap,aes(x=long,y=lat)) +
  geom_map(data = mymap,map = mymap,aes(group = group,map_id = id),fill = "#b2b2b2",color = "black",size = 0.3) +
  coord_sf(xlim=c(-80,-79.5),ylim=c(8.9,9.25),expand = FALSE) +
  geom_point(data = mypoint,aes(x = long,y = lat),size = 3) +
  geom_label(data = mypoint,aes(label = group,x = long,size = 3,fontface = "bold",nudge_x = c(0.015,0.02,0.022,0.018)) +
  geom_point(data = mypoint2,color = "blue",size = 3) +
  geom_label(data = mypoint2,nudge_x = c(-0.02,-0.018,-0.02,-0.02)) +
  scale_x_continuous(limits = c(-80,expand = c(0,0)) +
  scale_y_continuous(limits = c(8.9,0)) +
  theme_map() +
  ggsn::scalebar(location = "bottomleft",dist = 5,transform = TRUE,dist_unit = "km",model = 'WGS84',x.min = -79.97,x.max = -79.8,y.min = 8.93,y.max = 9.25) +
  north(x.min = -79.6,x.max = -79.5,y.min = 9.2,y.max = 9.24,location = "toprgiht",scale = 0.1)

g2 <- ggplotGrob(
  ggplot() +
    geom_polygon(data = mymap,y = lat,group = group),size = 0.3) +
    geom_point(data = mypoint,color = "red",size = 0.5) +
    coord_map("polyconic") +
    theme_map() +
    theme(panel.background = element_rect(fill = NULL))
)     

g3 <- g1 +
  annotation_custom(grob = g2,xmin = -79.75,xmax = -79.51,ymin = 8.9,ymax = 9.0)
g3