利用Python+xarray+cartopy+matplotlib 实现遥感地形图制图绘制 —— xarray 学习文档01

1. xarray

xarray是针对 “.nc” 等格式数据的处理软件，可以差值、可视化、合并等等操作！！！简单易上手
学习文档：xarray
安装：

pip install xarray

conda install xarray

2. xarray.plot() 数据可视化

以"海底地形数据"为例，只显示了中国东部海、中国南海以及西北太平洋等区域，也可以全球范围内

import xarray as xr
import cartopy.crs as ccrs
import cartopy.feature as cfeat
import numpy as np
from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER, mticker
import matplotlib.pyplot as plt

depth = xr.open_dataset(r"***\DEP\GEBCO_2021.nc")
data = dep['elevation']

lon = depth.lon
lat = depth.lat
lon_range = lon[(lon>=110)&(lon <=150)]
lat_range = lat[(lat >=5)& (lat<=45)]
dep = depth.sel(lat = lat_range,lon = lon_range)  

fig = plt.figure(figsize=(8,6),dpi=600)
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())
# 设置地图属性:加载国界、海岸线，land 为灰色
ax.add_feature(cfeat.OCEAN, zorder=0,color = 'white',edgecolor='black')
ax.add_feature(cfeat.LAND,  color = 'grey',zorder=1,edgecolor='black') 
ax.add_feature(cfeat.BORDERS.with_scale('50m'), linewidth=0.8, zorder=1)
ax.add_feature(cfeat.COASTLINE.with_scale('50m'), linewidth=0.6, zorder=1) 
ax.set_extent([110, 150,5, 45],crs = ccrs.PlateCarree())
# 设置网格点属性
gl = ax.gridlines(crs=ccrs.PlateCarree(), draw_labels=True, linewidth=1.2, color='gray', alpha=0.5, linestyle='--')
gl.top_labels = False   #关闭顶端标签
gl.right_labels = False #关闭右侧标签
gl.xlocator = mticker.FixedLocator([110,115,120,125,130,135,140,145,150])
gl.xformatter = LONGITUDE_FORMATTER#x轴设为经度格式
gl.xlabel_style = {'size':12, 'color': 'k','rotation':0}
gl.yformatter = LATITUDE_FORMATTER#y轴设为纬度格式
gl.ylocator = mticker.FixedLocator([5,10,15,20,25,30,35,40,45])
gl.ylabel_style = {'size':12,'rotation':0}
level = [-10000,-8000,-6000,-4000,-1500,-1000,-500,-100,0]

# 画图
im = data.plot(ax=ax, cmap='GnBu_r',vmin=-10000,vmax=0,levels = level,add_colorbar = False)#cbar_kwargs=cbar_kwargs,transform=ccrs.PlateCarree())
position2=fig.add_axes([0.22, 0.04, 0.57, 0.018])#位置[左,下,右,上]  0.25, 0.35, 0.5, 0.014
cb=plt.colorbar(im,cax=position2,orientation='horizontal')#方向
position2.set_title('Topography(m)',loc = 'center',fontsize=15,weight = 'normal')     

3. 结果显示