14、地理几何对象的创建与编辑

地理几何对象的创建与编辑

1. 从线创建点

有时候，我们需要将线的顶点提取为单独的点。下面的函数可以实现这一功能：

def line_to_point_layer(ds, line_name, pt_name):
    """Creates a point layer from vertices in a line layer."""
    if ds.GetLayer(pt_name):
        ds.DeleteLayer(pt_name)
    line_lyr = ds.GetLayer(line_name)
    sr = line_lyr.GetSpatialRef()
    pt_lyr = ds.CreateLayer(pt_name, sr, ogr.wkbPoint)     
    pt_lyr.CreateFields(line_lyr.schema)                              
    pt_feat = ogr.Feature(pt_lyr.GetLayerDefn())
    pt_geom = ogr.Geometry(ogr.wkbPoint)
    for line_feat in line_lyr:
        atts = line_feat.items()
        for fld_name in atts.keys():                                     
            pt_feat.SetField(fld_name, atts[fld_name])