更新时间:2023-11-25 18:36:40
当我将***拟合线应用于时间序列数据时,我会创建一条间隔均匀的线来表示日期以简化回归.所以我使用 np.linspace()
来创建一组等于日期数的间隔.
When I apply a best fit line to time series data, I create an evenly spaced line that represents the dates to simplify the regression. So I use np.linspace()
to create a set of intervals equal to the number of dates.
from io import StringIO
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
data = StringIO("""
date value
24-Jan-16 0.786
25-Feb-16 0.781
29-Apr-16 0.786
15-May-16 0.761
16-Jun-16 0.762
04-Sep-16 0.783
22-Oct-16 0.797
""")
df = pd.read_table(data, delim_whitespace=True)
# To read from csv use:
# df = pd.read_csv("/path/to/file.csv")
df.loc[:, "date"] = pd.to_datetime(df.loc[:, "date"], format="%d-%b-%y")
y_values = df.loc[:, "value"]
x_values = np.linspace(0,1,len(df.loc[:, "value"]))
poly_degree = 3
coeffs = np.polyfit(x_values, y_values, poly_degree)
poly_eqn = np.poly1d(coeffs)
y_hat = poly_eqn(x_values)
plt.figure(figsize=(12,8))
plt.plot(df.loc[:, "date"], df.loc[:,"value"], "ro")
plt.plot(df.loc[:, "date"],y_hat)
plt.title('WSC-10-50')
plt.ylabel('NDVI')
plt.xlabel('Date')
plt.savefig("NDVI_plot.png")