我绘制了瑞士的区域（多边形shapefile）并通过坐标添加了点（瑞士气象站）。
# Boundaries with data-points plotted
library(rgdal)
library(readxl)
library(sp)
library(ggplot2)
library(maptools)
library(plyr)
library(raster)
# import swiss country frontiers (.shp file)
gb <- readOGR("swissBOUNDARIES3D_1_3_TLM_KANTONSGEBIET.shp")
# import coordinates of weather stations from excel file (.xlsx)
coord <- read_excel("SMN-Stationen_20151222.xlsx")
head(coord)
# A tibble: 6 x 10
SINCE_DT NAT_IND_TX NAT_ABBR_TX NAME_TX X_KM_COORD_NU Y_KM_COORD_NU HEIGHT_ASL_NU
<dttm> <chr> <chr> <chr> <dbl> <dbl> <dbl>
1 2015-12-15 0600 ARO Arosa 771030 184826 1878
2 2015-10-27 3420 LAC Lachen / Galgenen 707637 226334 468
3 2015-09-08 8040 VEV Vevey …