在栅格tiff文件中查找次最小值

import gdal
import numpy as np

# 打开TIFF文件
dataset = gdal.Open('path_to_your_file.tif')
band = dataset.GetRasterBand(1)

# 读取数据到数组
data = band.ReadAsArray()

# 找到最小值和次最小值
min_value = np.min(data)
second_min_value = np.inf
for value in data.flatten():
    if min_value < value < second_min_value:
        second_min_value = value

print(f'次最小值是: {second_min_value}')

block_size = 1024
second_min_value = np.inf
for y in range(0, data.shape[0], block_size):
    for x in range(0, data.shape[1], block_size):
        block = data[y:y+block_size, x:x+block_size]
        min_in_block = np.min(block)
        if min_value < min_in_block < second_min_value:
            second_min_value = min_in_block

print(f'次最小值是: {second_min_value}')