用R绘制采样点地图一例

kibcat 2021-10-02

展开全文

# 绘制采样点分布图 version2
# by Jinlong Zhang
# jinlongzhang01@gmail.com

setwd('C:/Users/admin/Desktop/map') 
# 请根据用户名设定工作路径

#### 导入所需要的程序包
library(sf)

## Linking to GEOS 3.9.0, GDAL 3.2.1, PROJ 7.2.1

library(tmap)
library(tmaptools)
library(sp)
library(readxl)
library(grid)

rm(list = ls())

## 读取地图
country  <- read_sf('bou2_4l.shp') 
# 设定投影
st_crs(country) <- CRS(' proj=longlat  datum=WGS84') 


sites <-
  read_excel('location.xlsx') 
# 编辑location.xlsx文件，给出采样点，注意经纬度不要颠倒
head(sites)

## # A tibble: 3 x 3
##   name_location longitude latitude
##   <chr>             <dbl>    <dbl>
## 1 Beijing            116.     39.9
## 2 Guangzhou          113.     23.1
## 3 Harbin             127.     45.8

coordinates(sites) <- ~ longitude   latitude
proj4string(sites) <- CRS(' proj=longlat  datum=WGS84')

# 地图
map1 <-
  tm_shape(country, # 经度范围
           ylim = c(18, 54), xlim = c(70, 140))  
  tm_lines(col = 'darkgrey', lwd = 1)  

  tm_layout(
    title = 'Sampling sites',
    legend.position = c('left', 'bottom'),
    inner.margins = c(0.12, 0.03, 0.08, 0.03)
  )  
  tm_shape(sites)  
  tm_symbols(
    # 绘制采样点
    shape = 19,
    col = 'red',
    scale = 0.6,
    border.col = NA,
    title.shape = 'Sampling Sites',
    text = 'name_location',
    legend.col.show = TRUE
  )   
  # 显示采样点地名 
  tm_text(text = 'name_location', 
          just = 'bottom', size = 0.8)   
  # 添加经纬网
  tm_graticules(x = c(80, 90, 100, 110, 
                      120, 130, 140),
                y = c(0, 10, 20, 30, 
                      40, 50), 
                lwd = 0.5, col = 'lightgrey')   
  # 指北针
  tm_compass(type = 'arrow',
           position = c('left', 'top'))    
  # 比例尺
  tm_scale_bar(position = c('left', 'bottom'))   
  # 横轴
  tm_xlab('Longitude', size = 1)  
  # 纵轴
  tm_ylab('Latitude', size = 1)


# 南海诸岛小地图
map2 <-
  tm_shape(country,
           xlim = c(105, 122), # 经度范围
           ylim = c(2, 25))    # 纬度范围
  tm_lines(col = 'darkgrey', lwd = .8)  
  tm_layout(inner.margins = c(0.12, 0.03, 0.08, 0.03))  
  tm_shape(sites)  
  tm_dots(
    shape = 19,
    col = 'red',
    scale = 3,
    border.col = NA
  )  
  tm_text(text = 'name_location', just = 'bottom', 
          size = 0.5) # 显示采样点地名

# 保存为6英寸大小的pdf文件
# pdf('sampling_sites.pdf', width = 6, height = 6)
print(map1)

print(map2, vp = viewport(0.90, 0.25, width = 0.3, height = 0.25))

# dev.off()


# 保存为6英寸的tiff文件，lzw压缩，分辨率600dpi
# tiff(
#   'sampling_sites.tiff',
#   width = 3600,
#   height = 3600,
#   res = 600,
#   compression = 'lzw'
# )
# print(map1)
# print(map2, vp = viewport(0.90, 0.35, width = 0.3, height = 0.25))

# dev.off()

注意：本文地图仅供参考，不一定适于发表，因使用本代码和相应数据引致任何问题，本公众号以及维护人员概不负责。