用python提取nc数据的遥感反射率 结果定位不准确 导致提取结果不对 怎么修改

hehh

from netCDF4 import Dataset
import matplotlib.pyplot as plt
import numpy as np
# 打开nc文件
nc_file = Dataset('D:/s2-R/S2A_MSIL2A_20170402T024541_N9999_R132_T50SQD_20230829T231540_resampled.nc', 'r')

# 读取经纬度坐标
external_lat = 34.760832573916936   # 纬度
external_lon = 119.2084556187939  # 经度

DELTA=0.00004386
lon_index = np.where((nc_file.variables['lon'][:] >= external_lon - DELTA) & (nc_file.variables['lon'][:] <= external_lon + DELTA))[0]
lat_index = np.where((nc_file.variables['lat'][:] >= external_lat - DELTA) & (nc_file.variables['lat'][:] <= external_lat + DELTA))[0]

# # 定义波段名称列表
band_names = ['B1', 'B2', 'B3', 'B4', 'B5', 'B6', 'B7', 'B8', 'B8A', 'B9', 'B10', 'B11', 'B12']
# 读取各波段对应的遥感反射率数据

reflectance_data = {}
for band_name in band_names:
    if band_name in nc_file.variables:
        reflectance_data[band_name] = np.mean(nc_file.variables[band_name][lat_index, lon_index])
        print(f"{band_name}波段的平均遥感反射率为:", reflectance_data[band_name])
    else:
        print(f"警告：{band_name}波段缺失，跳过提取操作。")

# 关闭nc文件
nc_file.close()

hehh

有懂行的大佬 可以教教吗？