如何在python中进行第二次插值

我做了我的第一次插值和50个完整卫星轨道的经度值

现在，我只想看一个0-4.5度经度的窗口，然后做第二次插值，这样我在窗口中有6000个经度点

start = 0
stop = 4
num_points = 6000
arbitrary_time = np.linspace(start, stop, num_points)

我需要使用第一次插值的方程/曲线来创建第二次插值，因为窗口范围中只有一个点。我不知道如何进行第二次插值

输入：

lon = [-109.73105744378498, -104.28690174554579, -99.2435132929552, -94.48533149079628, -89.91054414962821, -85.42671400689177, -80.94616150449806, -76.38135021210172, -71.6402674905218, -66.62178379632216, -61.21120467960157, -55.27684029674759, -48.66970878028004, -41.23083703244677, -32.813881865289346, -23.332386757370532, -12.832819226213942, -1.5659455609661785, 10.008077792630402, 21.33116444634303, 31.92601575632583, 41.51883213364072, 50.04498630545507, 57.58103957109249, 64.26993028992476, 70.2708323505337, 75.73441871754586, 80.7944079829813, 85.56734813043659, 90.1558676264546, 94.65309120129724, 99.14730128118617, 103.72658922048785, 108.48349841714494, 113.51966824008079, 118.95024882101737, 124.9072309203375, 131.5395221402974, 139.00523971191907, 147.44847902856114, 156.95146022590976, 167.46163867248032, 178.72228750873975, -169.72898181991064, -158.44642409799974, -147.8993300787564, -138.35373014113995, -129.86955508919888, -122.36868103811106, -115.70852432245486]

myOrbitJ2000Time = [ 20027712.,  20027713.,  20027714.,  20027715.,  20027716.,
        20027717.,  20027718.,  20027719.,  20027720.,  20027721.,
        20027722.,  20027723.,  20027724.,  20027725.,  20027726.,
        20027727.,  20027728.,  20027729.,  20027730.,  20027731.,
        20027732.,  20027733.,  20027734.,  20027735.,  20027736.,
        20027737.,  20027738.,  20027739.,  20027740.,  20027741.,
        20027742.,  20027743.,  20027744.,  20027745.,  20027746.,
        20027747.,  20027748.,  20027749.,  20027750.,  20027751.,
        20027752.,  20027753.,  20027754.,  20027755.,  20027756.,
        20027757.,  20027758.,  20027759.,  20027760.,  20027761.]

代码：

deg = 30 #polynomial degree for fit
fittime = myOrbitJ2000Time - myOrbitJ2000Time[0]

'Longitude Interpolation'
fitLon = np.polyfit(fittime, lon, deg)   #gets fit coefficients
polyval_lon = np.polyval(fitLon,fittime) #interp.s to get actual values


'Get Longitude values for a window of 0-4.5 deg Longitude'
lonwindow =[]

for i in range(len(polyval_lon)):
    if 0 < polyval_lon[i] < 4.5:         # get lon vals in window
        lonwindow.append(polyval_lon[i]) #append lon vals

lonwindow = np.array(lonwindow)

deg=30#多项式拟合度
fittime=MyorbitJ2000时间-MyorbitJ2000时间[0]
“经度插值”
fitLon=np。多边形拟合（fittime，lon，deg）#获取拟合系数
polyval_lon=np.polyval（fitLon，fittime）#interp.s以获取实际值
'获取0-4.5度经度窗口的经度值'
lonwindow=[]
对于范围内的i（len（polyval_lon））：
如果0

首先，使用旧时间（x轴）值和内插经度（y轴）值生成多项式拟合系数

接下来，使用np.linspace（）根据窗口中所需的点数生成任意时间值

start = 0
stop = 4
num_points = 6000
arbitrary_time = np.linspace(start, stop, num_points)

最后，使用拟合系数和任意时间获得实际插值经度（y轴）值并绘制

lon_intrp_2 = np.polyval(polynomial_fit_coeff, arbitrary_time)

plt.plot(arbitrary_time, lon_intrp_2, 'r') #interpolated window as a red curve
plt.plot(myOrbitJ2000Time, lon, '.') #original data plotted as points