98 lines
4.1 KiB
Python
98 lines
4.1 KiB
Python
import rasterio
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from rasterio.windows import Window
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import geopandas as gpd
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from shapely.geometry import box
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import numpy as np
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import os
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# 参数设置
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image_path = 'path/to/your/image.tif' # 替换为您的影像路径（20000x20000）
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shapefile_path = 'path/to/your/shapefile.shp' # 替换为您的图斑Shapefile路径
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output_dir = 'path/to/output/tiles' # 输出切片目录
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tile_size = 1024 # 固定切片大小
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max_overlap_ratio = 0.2 # 重叠小于20%
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min_step = int(tile_size * (1 - max_overlap_ratio)) # 最小步长 ≈820
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# 创建输出目录
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os.makedirs(output_dir, exist_ok=True)
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# 读取影像
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with rasterio.open(image_path) as src:
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image_width, image_height = src.width, src.height
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assert image_width == 20000 and image_height == 20000, "影像大小不匹配"
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transform = src.transform # 地理变换矩阵
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# 读取图斑数据（假设CRS一致）
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gdf = gpd.read_file(shapefile_path)
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# 确保图斑CRS与影像一致，如果不一致需转换：gdf = gdf.to_crs(src.crs)
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# 初始化切片列表，避免重叠过多
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generated_windows = []
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for idx, row in gdf.iterrows():
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geom = row.geometry # 获取单个图斑多边形
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# 计算图斑的边界框 (minx, miny, maxx, maxy) - 像素坐标
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minx, miny, maxx, maxy = geom.bounds
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bbox_width = maxx - minx
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bbox_height = maxy - miny
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# 如果图斑太大，无法放入单个1024x1024切片，需处理（这里简单跳过，您可修改）
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if bbox_width > tile_size or bbox_height > tile_size:
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print(f"图斑 {idx} 太大 ({bbox_width}x{bbox_height})，跳过或需多切片处理")
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continue
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# 计算覆盖完整图斑的最小窗口：居中扩展到1024x1024
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center_x = (minx + maxx) / 2
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center_y = (miny + maxy) / 2
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half_tile = tile_size / 2
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win_minx = max(0, center_x - half_tile)
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win_miny = max(0, center_y - half_tile)
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win_maxx = min(image_width, center_x + half_tile)
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win_maxy = min(image_height, center_y + half_tile)
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# 调整以确保正好1024x1024（如果边界不足，padding或调整）
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if win_maxx - win_minx < tile_size:
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win_minx = max(0, win_maxx - tile_size)
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if win_maxy - win_miny < tile_size:
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win_miny = max(0, win_maxy - tile_size)
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proposed_window = Window(win_minx, win_miny, tile_size, tile_size)
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# 检查与现有窗口的重叠，确保<20%
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too_much_overlap = False
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for existing_win in generated_windows:
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# 计算重叠区域
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overlap_x = max(0, min(win_minx + tile_size, existing_win.col_off + tile_size) - max(win_minx, existing_win.col_off))
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overlap_y = max(0, min(win_miny + tile_size, existing_win.row_off + tile_size) - max(win_miny, existing_win.row_off))
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overlap_area = overlap_x * overlap_y
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if overlap_area > (tile_size * tile_size * max_overlap_ratio):
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too_much_overlap = True
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break
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if too_much_overlap:
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# 如果重叠太大，调整位置（这里简单跳过，您可实现更复杂的调整，如偏移步长）
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print(f"图斑 {idx} 的窗口重叠过多，跳过或调整")
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continue
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# 添加到列表
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generated_windows.append(proposed_window)
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# 裁剪并保存切片
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tile_data = src.read(window=proposed_window)
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tile_meta = src.meta.copy()
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tile_meta.update({
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'width': proposed_window.width,
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'height': proposed_window.height,
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'transform': rasterio.windows.transform(proposed_window, src.transform)
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})
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output_path = os.path.join(output_dir, f'tile_{idx}.tif')
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with rasterio.open(output_path, 'w', **tile_meta) as dst:
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dst.write(tile_data)
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print(f"生成切片 {output_path}，覆盖图斑 {idx}")
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print(f"总共生成 {len(generated_windows)} 个切片")
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# 注意：这个代码确保每个切片包含至少一个完整图斑，但可能有图斑被多个切片覆盖（如果重叠允许）。如果需要覆盖所有图斑的最优 tiling，请提供更多细节。
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