python - 如何使用 xarray、numpy 和 Basemap 从我的数据集中屏蔽海洋区域？

Question

我有一个 netCDF 文件“VWC_95percentile_by_seasons.nc”。它包含三个维度seasons（DJF、JJA、MAM、SON），latitude变量longitude名为VWC 95TH PERCENTILE.

变量打印如下：

<xarray.DataArray 'VWC 95TH PERCENTILE' (season: 4, latitude: 106, longitude: 193)>
dask.array<shape=(4, 106, 193), dtype=float64, chunksize=(4, 106, 193)>
Coordinates:
  * latitude   (latitude) float32 -39.2 -39.149525 ... -33.950478 -33.9
  * longitude  (longitude) float32 140.8 140.84792 140.89584 ... 149.95209 150.0
  * season     (season) object 'DJF' 'JJA' 'MAM' 'SON'

我需要在一个数字上为每个季节绘制一个图。每个地块都需要从海洋区域中屏蔽。

我的代码是：

import os
import time, datetime
import xarray as xr
import numpy as np
import pandas as pd
from glob import glob
import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap, maskoceans

shapefile1=r'{PATH}\shp\regions'

ds_path = r'{PATH}\output\VWC_95percentile_by_seasons.nc'
variable_name = 'VWC 95TH PERCENTILE'
lable = 'VWC'
title = 'VWC 95TH PERCENTILE'


print("### LOAD DATA")
ds = xr.open_mfdataset(ds_path)
da = ds[variable_name]
print(da)

print("### PLOTTING")

# define the colormap
cmap = plt.cm.jet
# extract all colors from the .jet map
cmaplist = [cmap(i) for i in range(cmap.N)]
# create the new map
cmap = cmap.from_list('Custom cmap', cmaplist, cmap.N)

# colour levels
levels=[0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50]

# Plot
p = da.plot(levels=10, cmap=cmap, x='longitude', y='latitude', col='season', cbar_kwargs={'label': lable})        # p is an instance of <class 'xarray.plot.facetgrid.FacetGrid'>
plt.suptitle(title)

for i, ax in enumerate(p.axes.flatten()):

    ax.set_xlabel('')
    ax.set_ylabel('')
    map = Basemap(llcrnrlat=-39.2,urcrnrlat=-33.9,llcrnrlon=140.8,urcrnrlon=150.0,resolution='i',ax=ax)
    map.readshapefile(shapefile1, 'regions', linewidth=0.5)    # draw disctict boundaries
plt.show()

目前绘制的是：

如何使用 xarray、numpy 和 Basemap 屏蔽所有海洋区域？

标签： pythonnumpymatplotlibmatplotlib-basemappython-xarray