1.导入cartopy库，认识一下常用的子模块
import cartopy.crs as ccrs
import cartopy.feature as cfeature
from cartopy.mpl.ticker import LongitudeFormatter, LatitudeFormatter
from cartopy.io.shapereader import Reader
from cartopy.feature.nightshade import Nightshade# 这些是其余要用到的库
import matplotlib.pyplot as plt
import matplotlib.path as mpath
import numpy as np
import datetime一、绘制地图底图
2.指定投影方式为等经纬度投影，绘制默认海岸线底图
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.coastlines()
3.在上一题的地图中，重新指定中心经度为180°
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.coastlines()
4.在上一题的地图中，指定绘制默认海岸线的线宽为0.3
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.coastlines(lw=0.3)
5.在中心经度为180°的等经纬度投影上，添加陆地
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
6.在上一题基础上，添加海洋
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
7.在上一题基础上，添加海岸线，并指定线宽为0.5
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
8.在上一题基础上，添加河流，并指定线宽为1.0
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
9.在上一题基础上，添加湖泊，并指定颜色为red
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
10.在上一题基础上，添加国境线，并指定线宽为0.1(不推荐使用，因为该默认参数会使得我国部分领土丢失)
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.add_feature(cfeature.BORDERS,lw=0.1)
11.在第9题的基础上，设置想要显示的经纬度标签值,x轴为(-180,-120,-60,0,60,120,180),y轴为(-90,-60, -30, 0, 30, 60,90)
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_xticks([ 0,60,120,180,240,300,360], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
12.在上一题的基础上，将经纬度标签转换为具有单位的形式
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_xticks([ 0,60,120,180,240,300,360], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
13.在上题的基础上，将刻度设置为灰色，并将其指向朝内
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_xticks([ -180,-120,-60,0,60,120,180], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.tick_params(color = 'gray',direction='in')
14.在上一题的基础上，选取经度为0°E-180°E，纬度为0°N-90°N的区域
代码语言：javascript复制#方法一
fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_xticks([ -180,-120,-60,0,60,120,180], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.set_extent([0,180,0,90],crs = ccrs.PlateCarree()) 
#方法二
fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_xticks([ -180,-120,-60,0,60,120,180], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.set_xlim(-180,0)
ax.set_ylim(0,90)15.在上一题的基础上，选择绘图的精度为50m，使得呈现出更多细节(第一次绘制会下载数据资源，时间大概需要几分钟，后面就不需要了)
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND.with_scale('50m'))
ax.add_feature(cfeature.OCEAN.with_scale('50m'))
ax.add_feature(cfeature.COASTLINE.with_scale('50m'),lw=0.5)
ax.add_feature(cfeature.RIVERS.with_scale('50m'),lw=1.0)
ax.add_feature(cfeature.LAKES.with_scale('50m'),color='r')
ax.set_xticks([ -180,-120,-60,0,60,120,180], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.set_extent([0,180,0,90],crs = ccrs.PlateCarree())
16.为第13题的图添加上虚线网格线
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_xticks([ -180,-120,-60,0,60,120,180], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.tick_params(color = 'gray',direction='in')
ax.gridlines(linestyle='--')
17.为上一题的图添加上标题“Cartopy”
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_xticks([ -180,-120,-60,0,60,120,180], crs=ccrs.PlateCarree())
ax.set_yticks([ -90,-60, -30, 0, 30, 60,90], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.tick_params(color = 'gray',direction='in')
ax.gridlines(linestyle='--')
ax.set_title('Cartopy')
二、自定义地图形状
18.设置一个梯形边界信息：纬度为60°S-60°N，上经度为40°E和140°E，下经度为20°E和160°E
代码语言：javascript复制vertices = [(20, -60), (40, 60), (140, 60), (160, -60), (20, -60)]#梯形的四个点，首尾相连。如第一个点为左下角的点，经度为20°N，纬度为60°S
boundary = mpath.Path(vertices)
boundaryPath(array([[ 20., -60.],
[ 40., 60.],
[140., 60.],
[160., -60.],
[ 20., -60.]]), None)19.在等经纬度投影中，截取出上一题的梯形地图，略去标签信息
代码语言：javascript复制fig = plt.figure(figsize=(4, 4), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.COASTLINE,lw=0.5)
ax.add_feature(cfeature.RIVERS,lw=1.0)
ax.add_feature(cfeature.LAKES,color='r')
ax.set_boundary(boundary, transform=ccrs.PlateCarree())
ax.set_extent([20,160,-60,60])
20.指定投影方式为兰伯特等角圆锥投影，并将中心经度设置为105°E，中心纬度设置为40°N
代码语言：javascript复制fig=plt.figure(figsize=(4,4),dpi=200)
ax=plt.axes(projection=ccrs.LambertConformal(central_longitude=105, central_latitude=40))
ax.add_feature(cfeature.LAND)
21.设定扇形边界信息：经度范围为65°E-145°E，纬度范围为10°N到60°N
代码语言：javascript复制vertices = [(65, 10), (65, 60),(145, 60), (145, 10), (65, 10)]
boundary = mpath.Path(vertices)22.在第20题的图中截取上一题的扇形区域
代码语言：javascript复制fig=plt.figure(figsize=(4,4),dpi=200)
ax=plt.axes(projection=ccrs.LambertConformal(central_longitude=105, central_latitude=40))
ax.add_feature(cfeature.LAND)
ax.set_boundary(boundary, transform=ccrs.PlateCarree())
ax.set_extent([65,145,0,60])
#进阶用法，通过增加点数使得边缘变得平滑
fig=plt.figure(figsize=(4,4),dpi=200)
ax=plt.axes([0,0,1,1],projection=ccrs.LambertConformal(central_longitude=105, central_latitude=40))
ax.add_feature(cfeature.LAND)#添加陆地
latmin = 10
latmax = 60
lonmin = 70
lonmax = 140
lats = np.linspace(latmax, latmin, latmax - latmin 1)
lons = np.linspace(lonmin, lonmax, lonmax - lonmin 1)
vertices = [(lon, latmin) for lon in range(lonmin, lonmax 1, 1)] [(lon, latmax) for lon in range(lonmax, lonmin - 1, -1)]
boundary = mpath.Path(vertices)
ax.set_boundary(boundary, transform=ccrs.PlateCarree())
ax.set_extent([lonmin,lonmax,latmin,latmax])
23.指定投影方式为极地立体投影
代码语言：javascript复制fig = plt.figure(figsize=(4,4),dpi=200)
ax = plt.axes(projection=ccrs.SouthPolarStereo())
ax.gridlines()
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
24.设定半圆的边界信息：以（0.5，0.5）为圆心，0.5为半径(注：整个圆的直径默认为1)
代码语言：javascript复制theta = np.linspace(0, np.pi, 100) #如果换成0.5*np.pi，就是四分之一圆了
center, radius = [0.5, 0.5], 0.5 #设定圆心和半径，范围是0-1
verts = np.vstack([np.sin(theta), np.cos(theta)]).T
circle = mpath.Path(verts * radius center)25.在23题的图中截取上一题的半圆形区域
代码语言：javascript复制fig = plt.figure(figsize=(4,4),dpi=200)
ax = plt.axes(projection=ccrs.SouthPolarStereo())
ax.gridlines()
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.set_boundary(circle, transform=ax.transAxes)
26.在上一题的基础上，加粗自定义的边界
代码语言：javascript复制fig = plt.figure(figsize=(4,4),dpi=200)
ax = plt.axes(projection=ccrs.SouthPolarStereo())
ax.gridlines()
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)
ax.set_boundary(circle, transform=ax.transAxes)
ax.outline_patch.set_linewidth(3) 
三、添加自定义的shape文件
27.设置shape文件的路径
代码语言：javascript复制shp_path=r'/home/china-shapefiles/china-shapefiles/china.shp'28.设定投影方式为等经纬度投影，并添加经纬度标签
代码语言：javascript复制fig = plt.figure(figsize=(2, 2), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.set_xticks([ 70,90,110,130], crs=ccrs.PlateCarree())
ax.set_yticks([ 0,20,40,60], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.set_extent([70,140,0,60], crs=ccrs.PlateCarree())
29.在上一题的基础上，读取中国shp文件中的地理信息，并添加到上一题的地图底图中
代码语言：javascript复制#方法一
fig = plt.figure(figsize=(2, 2), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.set_xticks([ 70,90,110,130], crs=ccrs.PlateCarree())
ax.set_yticks([ 0,20,40,60], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.set_extent([70,140,0,60], crs=ccrs.PlateCarree())
ax.add_geometries(Reader(shp_path).geometries(), ccrs.PlateCarree(), edgecolor='k', facecolor='g',linewidth=0.3)
#方法二
fig = plt.figure(figsize=(2, 2), dpi=200)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.set_xticks([ 70,90,110,130], crs=ccrs.PlateCarree())
ax.set_yticks([ 0,20,40,60], crs=ccrs.PlateCarree())
lon_formatter = LongitudeFormatter(zero_direction_label=False)
lat_formatter = LatitudeFormatter()
ax.xaxis.set_major_formatter(lon_formatter)
ax.yaxis.set_major_formatter(lat_formatter)
ax.set_extent([70,140,0,60], crs=ccrs.PlateCarree())
china = cfeature.ShapelyFeature(Reader(shp_path).geometries(), ccrs.PlateCarree(), edgecolor='k', facecolor='g', linewidth=0.3)
ax.add_feature(china)
四、填色图
30.生成纬度数据，从-90°~90°，分辨率为1°
代码语言：javascript复制nlats=181
lats = np.linspace(-90, 90 ,nlats)31.生成经度数据，从-180°~180°，分辨率为1°
代码语言：javascript复制nlons=361
lons = np.linspace(-180, 180 ,nlons)
lonsarray([-180., -179., -178., -177., -176., -175., -174., -173., -172.,
-171., -170., -169., -168., -167., -166., -165., -164., -163.,
-162., -161., -160., -159., -158., -157., -156., -155., -154.,
-153., -152., -151., -150., -149., -148., -147., -146., -145.,
-144., -143., -142., -141., -140., -139., -138., -137., -136.,
-135., -134., -133., -132., -131., -130., -129., -128., -127.,
-126., -125., -124., -123., -122., -121., -120., -119., -118.,
-117., -116., -115., -114., -113., -112., -111., -110., -109.,
-108., -107., -106., -105., -104., -103., -102., -101., -100.,
-99., -98., -97., -96., -95., -94., -93., -92., -91.,
-90., -89., -88., -87., -86., -85., -84., -83., -82.,
-81., -80., -79., -78., -77., -76., -75., -74., -73.,
-72., -71., -70., -69., -68., -67., -66., -65., -64.,
-63., -62., -61., -60., -59., -58., -57., -56., -55.,
-54., -53., -52., -51., -50., -49., -48., -47., -46.,
-45., -44., -43., -42., -41., -40., -39., -38., -37.,
-36., -35., -34., -33., -32., -31., -30., -29., -28.,
-27., -26., -25., -24., -23., -22., -21., -20., -19.,
-18., -17., -16., -15., -14., -13., -12., -11., -10.,
-9., -8., -7., -6., -5., -4., -3., -2., -1.,
0., 1., 2., 3., 4., 5., 6., 7., 8.,
9., 10., 11., 12., 13., 14., 15., 16., 17.,
18., 19., 20., 21., 22., 23., 24., 25., 26.,
27., 28., 29., 30., 31., 32., 33., 34., 35.,
36., 37., 38., 39., 40., 41., 42., 43., 44.,
45., 46., 47., 48., 49., 50., 51., 52., 53.,
54., 55., 56., 57., 58., 59., 60., 61., 62.,
63., 64., 65., 66., 67., 68., 69., 70., 71.,
72., 73., 74., 75., 76., 77., 78., 79., 80.,
81., 82., 83., 84., 85., 86., 87., 88., 89.,
90., 91., 92., 93., 94., 95., 96., 97., 98.,
99., 100., 101., 102., 103., 104., 105., 106., 107.,
108., 109., 110., 111., 112., 113., 114., 115., 116.,
117., 118., 119., 120., 121., 122., 123., 124., 125.,
126., 127., 128., 129., 130., 131., 132., 133., 134.,
135., 136., 137., 138., 139., 140., 141., 142., 143.,
144., 145., 146., 147., 148., 149., 150., 151., 152.,
153., 154., 155., 156., 157., 158., 159., 160., 161.,
162., 163., 164., 165., 166., 167., 168., 169., 170.,
171., 172., 173., 174., 175., 176., 177., 178., 179.,
180.])32.将刚刚生成的经纬度数据整合成网格数据
代码语言：javascript复制lons, lats = np.meshgrid(lons, lats)
lonsarray([[-180., -179., -178., ..., 178., 179., 180.],
[-180., -179., -178., ..., 178., 179., 180.],
[-180., -179., -178., ..., 178., 179., 180.],
...,
[-180., -179., -178., ..., 178., 179., 180.],
[-180., -179., -178., ..., 178., 179., 180.],
[-180., -179., -178., ..., 178., 179., 180.]])33.生成演示用的data，形状为(181,361),大小为0~181*361,间隔为1
代码语言：javascript复制data=np.arange(0,181*361,1).reshape(181,361)34.指定投影为等经纬度投影，将数据填充进去
代码语言：javascript复制fig = plt.figure(figsize=(10, 5))
ax = plt.axes(projection=ccrs.PlateCarree())
ax.contourf(lons, lats, data,transform=ccrs.PlateCarree())
ax.coastlines()
五、风场
35.随机在x,y处生成风速(x、y为坐标，u、v为x方向风速和y方向风速) 注：此处只是演示用，不必掌握，因为到时候大家的风场数据是从网站上或者模式中获得的，并不需要自己生成。
代码语言：javascript复制shape=(20, 30)
x = np.linspace(200, 391.1, shape[1])
y = np.linspace(-50, 50, shape[0])
x2d, y2d = np.meshgrid(x, y)
u = 10 * (2 * np.cos(2 * np.deg2rad(x2d) 3 * np.deg2rad(y2d 30)) ** 2)
v = 20 * np.cos(6 * np.deg2rad(x2d))36.指定等经纬度投影，绘制全球地图信息
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.LAND, edgecolor='black')
ax.set_global()
37.在上一题的地图底图上使用quiver函数绘制风场
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.LAND, edgecolor='black')
ax.set_global()
ax.quiver(x2d, y2d, u, v, transform=ccrs.PlateCarree())
六、流场
38.随机在x,y处生成风速(x、y为坐标，u、v为x方向风速和y方向风速)
代码语言：javascript复制shape=(20, 30)
x = np.linspace(1, 61, shape[1])
y = np.linspace(1, 41, shape[0])
x2d, y2d = np.meshgrid(x, y)
u = 10 * ( np.cos(x2d) 3 * np.sin(y2d) 30)
v = 20 * x2d39.在等经纬度投影的底图上绘制流场，指定线宽为2，密度为4，颜色根据风速大小改变
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = plt.axes(projection=ccrs.PlateCarree())
ax.add_feature(cfeature.OCEAN)
ax.add_feature(cfeature.LAND, edgecolor='black')
magnitude = (u ** 2 v ** 2) ** 0.5
ax.streamplot(x, y, u, v, transform=ccrs.PlateCarree(),linewidth=2, density=4,color=magnitude)
七、风向标
40.随机在x,y处生成风速(x、y为坐标，u、v为x方向风速和y方向风速)
代码语言：javascript复制shape=(20, 30)
x = np.linspace(200, 391.1, shape[1])
y = np.linspace(-50, 50, shape[0])
x2d, y2d = np.meshgrid(x, y)
u = 10 * (2 * np.cos(2 * np.deg2rad(x2d) 3 * np.deg2rad(y2d 30)) ** 2)
v = 20 * np.cos(6 * np.deg2rad(x2d))41.绘制地图底图
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())
ax.set_extent([-90, 80, 10, 85], crs=ccrs.PlateCarree())
ax.stock_img()
ax.coastlines()
42.利用ax.barbs将第38题的风向标绘制在上一题的地图上
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())
ax.set_extent([-90, 80, 10, 85], crs=ccrs.PlateCarree())
ax.stock_img()
ax.coastlines()
ax.barbs(x, y, u, v, length=5,
sizes=dict(emptybarb=0.25, spacing=0.2, height=0.5),
linewidth=0.95,alpha=0.5,transform=ccrs.PlateCarree())
八、夜影模式(0.17及以后版本的新功能)
43.利用ax.stock_img绘制默认地图背景
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = plt.axes(projection=ccrs.PlateCarree())
date = datetime.datetime(2022, 6, 4, 23)
ax.set_title(f'Night time shading for {date}')
ax.stock_img()
44.在上一题的基础上，添加夜影
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = plt.axes(projection=ccrs.PlateCarree())
date = datetime.datetime(2022, 6, 4, 23)
ax.set_title(f'Night time shading for {date}')
ax.stock_img()
ax.add_feature(Nightshade(date, alpha=0.2))
45.在当前目录下保存图片，并命名为Nightshade.png
代码语言：javascript复制fig = plt.figure(figsize=(10, 5), dpi=500)
ax = plt.axes(projection=ccrs.PlateCarree())
date = datetime.datetime(2022, 6, 4, 23)
ax.set_title(f'Night time shading for {date}')
ax.stock_img()
ax.add_feature(Nightshade(date, alpha=0.2))
plt.savefig('Nightshade.png')
