Python3之cartopy+matplotlib绘图

matplotlib官网
气象绘图参考网站
色标
地图选择器
ChinaMap
主要库cartopy绘制地图、matplotlib绘图
matplotlib 是从MATLAB启发而创建的，这俩的命令几乎一模一样，所以概念基本完全相同，可参考MATLAB官方文档
关键概念
Axes (笛卡尔坐标区）:
Axis (坐标轴）
Subplot (子图)
Plot (线图）
Figure (图窗)

绘图安装的库

conda install -c conda-forge numpy scipy pandas xarray geopandas matplotlib cartopy scikit-image metpy cfgrib
cartopy需要0.18.0conda install -c conda-forge cartopy=0.18.0

 import matplotlib.pyplot as plt

Figure创建窗口，类似于画板，Axes/Subplot创建子图，类似于画纸。所有的绘画只能在子图上进行。plt表示当前子图，若没有就创建一个子图
Figure：面板(图)，matplotlib中的所有图像都是位于figure对象中，一个图像只能有一个figure对象。
Subplot：子图，figure对象下创建一个或多个subplot对象(即axes)用于绘制图像。
配置参数：
axex: 设置坐标轴边界和表面的颜色、坐标刻度值大小和网格的显示
figure: 控制dpi、边界颜色、图形大小、和子区( subplot)设置
font: 字体集（font family）、字体大小和样式设置
grid: 设置网格颜色和线性
legend: 设置图例和其中的文本的显示
line: 设置线条（颜色、线型、宽度等）和标记
patch: 是填充2D空间的图形对象，如多边形和圆。控制线宽、颜色和抗锯齿设置等。
savefig: 可以对保存的图形进行单独设置。例如，设置渲染的文件的背景为白色。
verbose: 设置matplotlib在执行期间信息输出，如silent、helpful、debug和debug-annoying。
xticks和yticks: 为x,y轴的主刻度和次刻度设置颜色、大小、方向，以及标签大小。

1、坐标轴曲线

    x = np.arange(-5, 5, 0.1)y = x * 3fig = plt.figure() # 1个窗口简化写法# fig = plt.figure(num=1, figsize=(15, 8),dpi=80)     #详细写法，设置大小，分辨率ax1 = fig.add_subplot(2,1,1)  # 同fig.add_subplot(211)通过fig添加子图，参数：行数，列数，第几个。1个可省略# 括号里面的值前两个是轴域原点坐标（从左下角计算的），后两个是显示坐标轴的长度。ax1 = fig.add_axes([0.1, 0.1, 0.8, 0.8]) #add_axes()生成子图的灵活性更强，完全可以实现add_subplot()方法的功能# ax2 = fig.add_subplot(2,1,2)  #通过fig添加子图，参数：行数，列数，第几个。1个可省略# ax1 = fig.add_subplot(111, facecolor='r') #设置背景颜色plt.plot(x, y) # 画图plt.scatter(x, y, c='r') # 设置颜色plt.xlabel('X Axis') #设置x轴名称 ax1.set_xlabelplt.ylabel('Y Axis') #设置Y轴名称 ax1.set_ylabelplt.title('this is a demo') # 设置标题plt.xlim((-5, 5)) # 设置横轴范围 ax1.set_xlim 可略，默认x,y 所有值范围plt.ylim((-15, 15)) # 设置纵轴范围 ax1.set_ylim 可略plt.savefig('d:/f.png') # 保存图片，plt.savefig('aa.jpg', dpi=400, bbox_inches='tight') dpi分辨率，bbox_inches子图周边白色空间的大小# 左右下上4个轴# 设置轴的位置ax1.spines['left'].set_position('center')# 设置轴的颜色ax1.spines['right'].set_color('none')# 设置轴的位置ax1.spines['bottom'].set_position('center')# 设置轴的颜色ax1.spines['top'].set_color('none')# 显示网格。which参数的值为major(只绘制大刻度)、minor(只绘制小刻度)、both，默认值为major。axis为'x','y','both'ax1.grid(b=True, which='major', axis='both', alpha=0.5, color='skyblue', linestyle='--', linewidth=2)# ax1.set_xticks([])  # 去除坐标轴刻度ax1.set_xticks((-5, -3, -1, 1, 3, 5))  # 设置坐标轴刻度ax1.text(2.8, 7, r'y=3*x')  # 指定位置显示文字,plt.text()axes1 = plt.axes([.2, .3, .1, .1], facecolor='y')  # 在当前窗口添加一个子图，rect=[左, 下, 宽, 高]，是使用的绝对布局，不和以存在窗口挤占空间axes1.plot(x, y)  # 在图上画子图ax1.annotate('important point', xy=(2, 6), xytext=(3, 1.5),  # 添加标注，参数：注释文本、指向点、文字位置、箭头属性arrowprops=dict(facecolor='black', shrink=0.05),)plt.show() #所有窗口运行ax.invert_yaxis() # 反转y轴

2、绘制轮廓

1、类似于等高线(等值线) matplotlib.pyplot.contour

# 高斯滤波，K为黑色轮廓
cs = ax.contour(dat.latitude.values, dat.level.values,gaussian_filter(dat.values, 2), colors='k')

2、填充轮廓（色斑图） contourf

ax.contourf(abn.latitude.values, abn.level.values,abn.values, extend='both', levels=level_abn,cmap=cmap_abn, norm=norm_abn)

3、风杆图

        default_barb_style = {'length': 5,'sizes': {'emptybarb': 0.25, 'spacing': 0.2, 'height': 0.5},'barb_increments': {'half': 2, 'full': 4, 'flag': 20},'flagcolor': 'grey'}ax.barbs(lon, lat, u, v, transform=ccrs.PlateCarree(), **default_barb_style)

4、色标

import matplotlib.pyplot as plt# norm = mpl.colors.Normalize(vmin=-10, vmax=10)lvs = np.arange(-10, 11, 1)cf = ax.contourf(lon_var, lat_var,2 * dat_a.to(units('delta_degC/sec')) * 1e4, extend='both',levels=lvs, cmap=plt.get_cmap('RdBu_r'), # norm=norm,transform=ccrs.PlateCarree())cax = add_axes(fig, ax_provision)cb = fig.colorbar(cf, cax=cax, extend='both', fraction=0.03,extendfrac='auto', extendrect=True, drawedges=True)cb.set_ticks(lvs) # 设置色标刻度cb.ax.tick_params(labelsize=14)

norm :用于规范化–设置颜色条最大最小值
RdBu_r是RdBu色带的倒转

5、设置y轴比例 matplotlib.axes.Axes.set_yscale

# 仅绘制正值 正整数 int序列
ax.set_yscale('log') # 默认值：'clip'

b=蓝色 g=绿色 r=红色 y=黄色 c=青色 k=黑色 m=洋红色 w=白色

6、10的-4次方描述

f'$10^{{-4}}$'

7、中文显示问题

import matplotlib
# 指定默认字体
matplotlib.rcParams['font.sans-serif'] = ['SimHei']
matplotlib.rcParams['font.family'] ='sans-serif'
# 解决负号'-'显示为方块的问题
matplotlib.rcParams['axes.unicode_minus'] = False

查看centos是否有中文

fc-list :lang=zh #fc-list :lang=zh family

>>> import matplotlib
>>> matplotlib.matplotlib_fname()
'/data/software/anaconda3/envs/py36/lib/python3.6/site-packages/matplotlib/mpl-data/matplotlibrc'

字体目录

/data/software/anaconda3/envs/py36/lib/python3.6/site-packages/matplotlib/mpl-data/fonts/ttf/

当前字体种类

 from matplotlib import font_managerfor font in font_manager.fontManager.ttflist:print(font.name, '-', font.fname)

注意：matplotlib版本影响字体属性

         [l.set_family("Times New Roman") for l in cb.ax.yaxis.get_ticklabels()]#gl.xlabel_style = {'size': 14, 'fontfamily': 'Times New Roman'}gl.xlabel_style = {'size': 14, 'family': 'Times New Roman'}gl.ylabel_style = {'size': 14, 'family': 'Times New Roman'}

注： https://mathsyouth.github.io/2019/06/12/macos-matplotlib

Cartopy

1、安装Cartopy库0.18.0，必须的库Shapely、pyshp

conda install -c conda-forge cartopy=0.18.0

import matplotlib.pyplot as plt
import cartopy.crs as ccrsplt.figure(figsize=(6, 3))
ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
ax.coastlines(resolution='110m')
ax.gridlines()

可以运行即可
2、下载地图数据 http://www.naturalearthdata.com/downloads/
有三种分辨率的shape地图数据，分别下载三种分辨率中的physical数据中的Coastline和Land数据，
如：ne_10m_coastline.zip，解压后copy到文件夹C:\Users\Administrator.local\share\cartopy\shapefiles\natural_earth\physical
运行1中的程序后，程序会自动创建physical文件夹，默认使用110m分辨率
下载最新版本失败，就下载历史版本
注：如果想使用自己的地图，比如我有一个带我国法定边界的地图shape文件，名为：World.shp、World.shx、World.dbf、World.prj，重新命名为10m_coastline或10m_land文件（这里要根据该shape文件是line型还是polygon型），替换原目录下的shape文件，画图时使用scale为10m即调用到了自己的地图

色斑图示例

import os
import logging
from pathlib import Pathimport numpy as np
import matplotlib.pyplot as plt
from matplotlib import font_manager
import cartopy.crs as ccrs
from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER
from matplotlib import cm
import geopandas as gpdimport configMODULE_NAME = os.path.split(__file__)[-1].split(".")[0]
logger = logging.getLogger(f'module.utils.{MODULE_NAME}')
gdf = gpd.GeoDataFrame.from_file(os.path.join(config.JSON_ROOT, 'shandong', 'shandong.json'))
plt.rcParams['font.family'] = 'sans-serif'
plt.rcParams['font.sans-serif'] = ['SimHei', 'DejaVu Sans', 'Microsoft YaHei', 'TimesNewRoman', 'Arial']
plt.rcParams['axes.unicode_minus'] = Falsefont_dirs = [os.path.join(config.STATIC_PATH, 'font'), ]
font_files = font_manager.findSystemFonts(fontpaths=font_dirs)
if hasattr(font_manager.fontManager, 'addfont') and callable(font_manager.fontManager.addfont):[font_manager.fontManager.addfont(font) for font in font_files]
else:font_list = font_manager.createFontList(font_files)font_manager.fontManager.ttflist.extend(font_list)def run():micaps4 = '/test/2021012510'time = Path(micaps4).namefile = open(micaps4, mode='rt', encoding='gbk')tmp = file.readlines()row = int(tmp[0].strip().split()[16])  # 行数column = int(tmp[0].strip().split()[15])  # 列数min_lat = float(tmp[0].strip().split()[13])max_lat = float(tmp[0].strip().split()[14])min_lon = float(tmp[0].strip().split()[11])max_lon = float(tmp[0].strip().split()[12])lat_step = float(tmp[0].strip().split()[10])lon_step = float(tmp[0].strip().split()[9])logger.debug(f'micaps4 :{row, column, min_lat, max_lat, min_lon, max_lon, lat_step, lon_step}')lons = np.linspace(min_lon, max_lon, column)lats = np.linspace(min_lat, max_lat, row)tmp.pop(0)grid_data = np.zeros((row, column))for i in range(0, row):aa = tmp[i].strip().split()for j in range(len(aa)):grid_data[i][j] = float(aa[j])logger.debug(f'plot region: {(min_lon, max_lon, min_lat, max_lat)}')fig = plt.figure(dpi=150)ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())ax.set_extent((min_lon, max_lon, min_lat, max_lat), crs=ccrs.PlateCarree())# ax.coastlines(linewidth=0.5) #边界gridlines_style = {'draw_labels': True, 'linestyle': '--', 'alpha': 0.7}gl = ax.gridlines(ylocs=np.linspace(min_lat, max_lat, 1),xlocs=np.linspace(min_lon, max_lon, 1),**gridlines_style)gl.xlabels_top = False  # 关闭顶端的经纬度标签 gl.top_labels = Falsegl.ylabels_right = False  # 关闭右侧的经纬度标签 gl.right_labels = Falsegl.xformatter = LONGITUDE_FORMATTER  # x轴设为经度的格式gl.yformatter = LATITUDE_FORMATTER  # y轴设为纬度的格式name_station = {"济南": [117, 36.65]}for key, value in name_station.items():  # 打印站点ax.scatter(value[0], value[1], marker='.', s=60, color="k", zorder=3)ax.text(value[0] - 0.07, value[1] + 0.03, key, fontsize=7, color="k")title_main = f'山东省{time} 时温度色斑图'title_sub = f"副标题xxx"ax.set_title(f'{title_main} \n {title_sub}', fontsize=18)ax.set_title(f'阈值: ', loc='right', fontsize=16)ax.add_geometries(gdf['geometry'], crs=ccrs.PlateCarree(), facecolor='', edgecolor='#2B2B2B')# ax.add_geometries(gdf['geometry'][0], crs=ccrs.PlateCarree(), facecolor='', edgecolor='#2B2B2B') #仅显示济南市cf = ax.contourf(lons, lats, grid_data,transform=ccrs.PlateCarree(),cmap=cm.get_cmap('bwr'))cb = fig.colorbar(cf, orientation='horizontal', shrink=0.8)cb.ax.tick_params(labelsize=14)[l.set_family("Times New Roman") for l in cb.ax.yaxis.get_ticklabels()]gl.xlabel_style = {'size': 14, 'family': 'Times New Roman'}gl.ylabel_style = {'size': 14, 'family': 'Times New Roman'}[i.set_linewidth(2) for i in ax.spines.values()]file_name = f'{time}.png'save_file = Path(config.ROOT_PATH) / 'png' / 'seban' / file_nameif not save_file.parent.exists():save_file.parent.mkdir(parents=True)fig.savefig(save_file, dpi=100)

错误

1、linux运行py弹窗：需要Xmanager软件来处理X11转发请求

import matplotlib
matplotlib.use('Agg') #使用非交互式后端，避免创建窗口
import matplotlib.pyplot as plt  # matplotlib.use('Agg')必须在本句执行前运行

参考：
https://www.zhihu.com/question/51745620
https://www.jianshu.com/p/da385a35f68d
https://scitools.org.uk/cartopy/docs/latest/matplotlib/advanced_plotting.html
http://bbs.06climate.com/forum.php?mod=viewthread&tid=33601&extra=page%3D1

2、Reinstalling the application may fix this problem. 已放弃(吐核)

通过strace python xxx.py跟踪

stat("/data/software/anaconda3/envs/py36/bin/qt.conf", {st_mode=S_IFREG|0775, st_size=201, ...}) = 0
stat("/data/software/anaconda3/envs/py36/bin/qt.conf", {st_mode=S_IFREG|0775, st_size=201, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=405, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=405, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=405, ...}) = 0
stat("/opt/anaconda1anaconda2anaconda3/plugins", 0x7fffc834d1a0) = -1 ENOENT (No such file or directory) ##注意该处，路径错误
lstat("/data", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/data/software", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/data/software/anaconda3", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/data/software/anaconda3/envs", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/data/software/anaconda3/envs/py36", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/data/software/anaconda3/envs/py36/bin", {st_mode=S_IFDIR|0755, st_size=12288, ...}) = 0
stat("/data/software/anaconda3/envs/py36/bin", {st_mode=S_IFDIR|0755, st_size=12288, ...}) = 0
stat("/data/software/anaconda3/envs/py36/bin/platforms/.", 0x7fffc834d1d0) = -1 ENOENT (No such file or directory)
open("/opt/anaconda1anaconda2anaconda3/qtlogging.ini", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat("/root/.config/QtProject/qtlogging.ini", 0x7fffc834d100) = -1 ENOENT (No such file or directory)
stat("/etc/xdg/QtProject/qtlogging.ini", 0x7fffc834d100) = -1 ENOENT (No such file or directory)
open("/dev/tty", O_RDONLY|O_CLOEXEC)    = 4
fcntl(4, F_SETFD, FD_CLOEXEC)           = 0
close(4)                                = 0
write(2, "This application failed to start"..., 155This application failed to start because it could not find or load the Qt platform plugin "xcb"
in "".Reinstalling the application may fix this problem.
) = 155
rt_sigprocmask(SIG_UNBLOCK, [ABRT], NULL, 8) = 0
tgkill(159944, 159944, SIGABRT)         = 0
--- SIGABRT {si_signo=SIGABRT, si_code=SI_TKILL, si_pid=159944, si_uid=0} ---
+++ killed by SIGABRT (core dumped) +++
已放弃(吐核)

缺少PyQt5库

"qt.qpa.screen: QXcbConnection: C"..., 75qt.qpa.screen: QXcbConnection: Could not connect to display localhost:10.0

解决方案很简单：
export DISPLAY=':0.0'
如果不行的话则尝试
export DISPLAY=':1.0'或export DISPLAY=':2.0'
至于为何时1.0或2.0或0.0,
可以在终端执行：
echo ${DISPLAY}
显示的是什么配置成什么就行了

3、matplotlib错误ValueError: Expected 2-dimensional array, got 1

#ax.add_geometries(gdf['geometry'], crs=ccrs.PlateCarree(), facecolor='', edgecolor='#2B2B2B')
ax.add_geometries(gdf['geometry'], crs=ccrs.PlateCarree(), facecolor='none', edgecolor='#2B2B2B')