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- from qgis._core import QgsRectangle
- from qgis.core import QgsVectorLayer, QgsFeature, QgsGeometry, QgsVectorFileWriter, QgsField, QgsWkbTypes
- from PyQt5.QtCore import QVariant
- # 输入shapefile路径
- input_shp = "E:\\projects\\遥感技术部需求\\裁剪栅格\\data\\grid.shp"
- # 输出shapefile路径
- output_shp = "E:\\projects\\遥感技术部需求\\裁剪栅格\\data\\grid_extent.shp"
- expand_distance = 50
- # 加载输入shapefile
- input_layer = QgsVectorLayer(input_shp, "input_layer", "ogr")
- if not input_layer.isValid():
- print(f"Failed to load input shapefile: {input_shp}")
- else:
- # 获取输入图层的字段信息
- fields = input_layer.fields()
- # 创建输出shapefile
- writer = QgsVectorFileWriter(output_shp, 'UTF-8', fields, QgsWkbTypes.MultiPolygon, input_layer.crs(),
- 'ESRI Shapefile')
- output_layer = QgsVectorLayer(output_shp, "output_shp", "ogr")
- # 检查文件是否成功创建
- if writer.hasError() != QgsVectorFileWriter.NoError:
- print(f"Error creating output shapefile: {output_shp}")
- else:
- # 遍历输入shapefile中的要素
- for feature in input_layer.getFeatures():
- # 获取要素的geometry和extent
- geometry = feature.geometry()
- extent = geometry.boundingBox() # 获取要素的extent（bounding box）
- # 对extent进行外扩
- # 使用 grow 方法来将bounding box外扩100米
- # extent.grow(expand_distance) # 扩展100米
- # print(f"Feature ID: {feature.id()}, Extent: {extent}")
- # 获取四至坐标
- minX = extent.xMinimum()
- maxX = extent.xMaximum()
- minY = extent.yMinimum()
- maxY = extent.yMaximum()
- # 手动扩展extent，向四个方向扩展100米
- expanded_minX = minX - expand_distance # 向左扩展
- expanded_maxX = maxX + expand_distance # 向右扩展
- expanded_minY = minY - expand_distance # 向下扩展
- expanded_maxY = maxY + expand_distance # 向上扩展
- # 创建新的扩展后的QgsRectangle
- expanded_extent = QgsRectangle(expanded_minX, expanded_minY, expanded_maxX, expanded_maxY)
- # 使用extent创建一个新的几何（矩形geometry）
- new_geometry = QgsGeometry.fromRect(expanded_extent)
- # 创建一个新的要素，并将新几何设置到要素中
- new_feature = QgsFeature(fields) # 创建新的空要素，使用相同的字段定义
- new_feature.setGeometry(new_geometry) # 设置新的几何（extent）
- # 复制原始要素的属性到新的要素
- new_feature.setAttributes(feature.attributes()) # 将原要素的属性复制到新要素
- # 将修改后的要素添加到输出shapefile
- writer.addFeature(new_feature)
- # 完成写入并关闭输出文件
- del writer
- print(f"Features copied from {input_shp} to {output_shp} with modified extent.")
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