Python 用ogr实现把一个矢量图层的属性字段赋给新创建的图层

使用 ogr 可以很方便地实现将一个矢量图层的属性字段赋给新创建的图层。

以下是一个示例代码，假设我们有一个名为“old_layer.shp”的矢量图层，现在要创建一个名为“new_layer.shp”的图层，并将“old_layer.shp”的属性字段赋值给“new_layer.shp”：

from osgeo import ogr

# 打开旧图层
old_ds = ogr.Open('old_layer.shp', 0)
old_layer = old_ds.GetLayer()

# 创建新图层
new_ds = ogr.GetDriverByName('ESRI Shapefile').CreateDataSource('new_layer.shp')
new_layer = new_ds.CreateLayer('new_layer', geom_type=ogr.wkbPolygon)

# 将旧图层的属性表结构复制到新图层
new_layer_def = old_layer.GetLayerDefn()
for i in range(new_layer_def.GetFieldCount()):
    field_def = new_layer_def.GetFieldDefn(i)
    new_layer.CreateField(field_def)

# 将旧图层的属性值复制到新图层
new_layer.StartTransaction()
for old_feature in old_layer:
    new_feature = ogr.Feature(new_layer_def)
    for i in range(new_layer_def.GetFieldCount()):
        field_def = new_layer_def.GetFieldDefn(i)
        field_value = old_feature.GetField(field_def.name)
        new_feature.SetField(field_def.name, field_value)
    new_geometry = old_feature.GetGeometryRef().Clone()
    new_feature.SetGeometry(new_geometry)
    new_layer.CreateFeature(new_feature)
    new_feature = None
new_layer.CommitTransaction()

# 清理
old_layer = None
old_ds = None
new_layer = None
new_ds = None

在这个示例代码中，我们首先打开旧图层“old_layer.shp”，然后创建新图层“new_layer.shp”。接着，我们将旧图层的属性表结构复制到新图层，并将旧图层的属性值复制到新图层。最后，我们清理并关闭数据源和图层。

注意，如果要将某个属性字段的值进行操作并赋值给新图层的属性字段，可以在复制属性值的过程中进行处理。