如何在循环中以某些xy值自动注释点或线

编程问答 2022-06-20

问题描述

嗨，我成功地使用for in循环从excel数据创建了多个压力和温度等图形，并生成了多个png文件。我在下面附上了脚本

是否可以在230摄氏度的温度与温度线图（蓝色虚线）相交的地方自动创建一条线或注释（红色划痕）？

figure

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np

path ='F:\Backup\JN\TOR\TOR HLS py.xlsx'
data= pd.ExcelFile(path)

sheets = data.sheet_names
well = ''

for i in sheets:
    well=pd.read_excel(data,sheet_name=i)
    fig=plt.figure(figsize=(8,12),constrained_layout='True')
    plt.plot(well['x csg'],well['mdpl csg'],marker='s',linestyle='solid',color='black')
    plt.plot(well['x liner'],well['mdpl liner'],linestyle='dotted',color='black')
    plt.plot(well['T'],well['mdpl pt'],marker='o',color='blue',label='Temperature')
    plt.plot(well['P'],color='crimson',label='Pressure')
    for x,txt in enumerate(well['csg']):
        plt.annotate(txt,((well['x csg']+5)[x],well['mdpl csg'][x]),size=8)
    for y,txt in enumerate(well['liner']):
        plt.annotate(txt,((well['x liner']+5)[y],well['mdpl liner'][y]),size=8)
    plt.savefig(str(i),dpi=300,transparent='True')
    plt.close(i)

请帮助，谢谢

解决方法

请检查代码段。我建议您使用shapely库来计算2条线之间的交点。如果路径不使用相同的X轴值，则此方法也适用。您将获得可以使用循环注释的交叉点。 Intersection 

from matplotlib import pyplot as plt
import numpy as np
import shapely
from shapely.geometry import LineString,Point

x = np.linspace(0,5,20)
y1 = x**2
y2 = 3*x

za1=[(i,j) for i,j in zip(x,y1)]    #points for (x,y) line1
za2=[(i,y2)]    #points for (x,y) line2

line1 = LineString(za1)
line2 = LineString(za2)

intersection = line1.intersection(line2)
intersect_points = [list(p.coords)[0] for p in intersection]
print(intersect_points)
#[(0.0,0.0),(2.994555353901996,8.983666061705987)]     point of intersection

fig,ax = plt.subplots()
plt.plot(x,y1,color='lightcoral')
plt.plot(x,y2,color='#4b0082')

for i in intersect_points:
  ax.annotate('x',xy=(i),fontsize=20,color='red')
plt.show()

您可以在Shapely此处查看有关Shapely的更多信息

,

我只是从x中找到内插的y值，然后用直线注释该内插的y值

y230=float(np.interp(xval,well['T'],well['mdpl pt']))
if math.isnan(y230) == False:
    plt.annotate('ToR 230 $^o$C',xy=(200,y230),xytext=(250,(y230-9)),arrowprops=dict(color='green',arrowstyle="-",lw=2))
annotatematplotlibpandaspandasplotpython