需求:需要根据栅格范围裁剪矢量数据。但是查到的资料都是矢量数据裁剪栅格。
两种解决方法,arcgis/python
1、arcgis(思路栅格转矢量,先提取栅格外边界或者栅格转矢量)
下图的工具可以提取栅格的外边界数据。
下图是栅格转矢量(数据量大不建议这个工具)
转换以后就可以采用相交工具提取相交部分的矢量
有时候不知道什么原因上面两个工具转换不成功,python解决(获取的不仅有每个格子边界,还有栅格边界,获取以后再arcgis上选中导出即可同步骤1)
import os
from osgeo import gdal, ogr, osr
import numpy as np
def raster_to_vector_boundary(input_raster_path, output_vector_path, threshold=0, band_index=1,
simplify_tolerance=None):
"""
将栅格数据的外边界提取为矢量格式
参数:
input_raster_path (str): 输入栅格文件路径
output_vector_path (str): 输出矢量文件路径
threshold (float): 二值化阈值,大于此值的像素被视为有效区域
band_index (int): 要处理的波段索引,从1开始
simplify_tolerance (float): 边界简化容差,用于减少矢量顶点数量
"""
# 打开栅格数据集
raster_ds = gdal.Open(input_raster_path)
if raster_ds is None:
raise FileNotFoundError(f"无法打开栅格文件: {input_raster_path}")
# 获取栅格波段
band = raster_ds.GetRasterBand(band_index)
if band is None:
raise ValueError(f"栅格中不存在索引为 {band_index} 的波段")
# 读取栅格数据为numpy数组
raster_array = band.ReadAsArray()
# 创建二值化掩膜(大于阈值的像素为1,否则为0)
mask_array = np.where(raster_array > threshold, 1, 0).astype(np.uint8)
# 获取栅格投影和地理变换信息
projection = raster_ds.GetProjection()
geotransform = raster_ds.GetGeoTransform()
# 创建临时内存栅格用于存储掩膜
driver = gdal.GetDriverByName('MEM')
mask_ds = driver.Create('', raster_ds.RasterXSize, raster_ds.RasterYSize, 1, gdal.GDT_Byte)
mask_ds.SetProjection(projection)
mask_ds.SetGeoTransform(geotransform)
mask_band = mask_ds.GetRasterBand(1)
mask_band.WriteArray(mask_array)
mask_band.FlushCache()
# 创建输出矢量数据集
vector_driver = ogr.GetDriverByName('GeoJSON') if output_vector_path.lower().endswith(
'.geojson') else ogr.GetDriverByName('ESRI Shapefile')
# 如果输出文件已存在,删除它
if os.path.exists(output_vector_path):
vector_driver.DeleteDataSource(output_vector_path)
vector_ds = vector_driver.CreateDataSource(output_vector_path)
if vector_ds is None:
raise RuntimeError(f"无法创建矢量文件: {output_vector_path}")
# 创建图层
srs = osr.SpatialReference()
srs.ImportFromWkt(projection)
layer = vector_ds.CreateLayer('boundary', srs, ogr.wkbPolygon)
# 创建字段用于存储面积
area_field = ogr.FieldDefn('area', ogr.OFTReal)
layer.CreateField(area_field)
# 执行栅格到矢量的转换
gdal.Polygonize(mask_band, None, layer, 0, [], callback=None)
# 遍历所有要素并简化边界(如果指定了容差)
if simplify_tolerance is not None and simplify_tolerance > 0:
for feature in layer:
geom = feature.GetGeometryRef()
simplified_geom = geom.SimplifyPreserveTopology(simplify_tolerance)
feature.SetGeometry(simplified_geom)
layer.SetFeature(feature)
# 计算并设置面积字段
for feature in layer:
geom = feature.GetGeometryRef()
area = geom.GetArea()
feature.SetField('area', area)
layer.SetFeature(feature)
# 释放资源
raster_ds = None
mask_ds = None
vector_ds = None
print(f"成功将栅格外边界提取为矢量数据并保存至: {output_vector_path}")
if __name__ == "__main__":
# 栅格文件路径(根据你的提供设置)
input_raster_path = r"G:\**\***\result.tif"
# 输出矢量文件路径(默认为栅格所在目录下的boundary.shp)
output_dir = r"G:\***\****"
output_vector_path = os.path.join(output_dir, "boundary.shp")
# 处理参数
threshold = 0 # 二值化阈值,根据实际情况调整
band_index = 1 # 处理第一个波段
simplify_tolerance = 10 # 边界简化容差,可根据需要调整或设为None不简化
try:
# 执行栅格到矢量的转换
raster_to_vector_boundary(
input_raster_path,
output_vector_path,
threshold=threshold,
band_index=band_index,
simplify_tolerance=simplify_tolerance
)
except Exception as e:
print(f"处理过程中发生错误: {str(e)}")