shputils.py 文件源码

def polygon_to_shapefile(polygons, poly_sr, fname, fields_defs=None,
                         poly_attrs=None):
    """
    Write a set of polygons to a shapefile
    Args:
        polygons: a list of (lat, lng) tuples
        fields_defs: The list of fields for those polygons, as a tuple
                     (name, ogr type) for each field. For example :
                     [('field1', ogr.OFTReal), ('field2', ogr.OFTInteger)]
        poly_attrs: A list of dict containing the attributes for each polygon
                        [{'field1' : 1.0, 'field2': 42},
                         {'field1' : 3.0, 'field2': 60}]
    """
    shp_driver = ogr.GetDriverByName("ESRI Shapefile")
    out_ds = shp_driver.CreateDataSource(fname)
    assert out_ds is not None, "Failed to create temporary %s" % fname
    out_layer = out_ds.CreateLayer(fname, poly_sr, geom_type=ogr.wkbPolygon)

    has_attrs = fields_defs is not None
    if has_attrs:
        attrs_name = []
        for field_name, field_type in fields_defs:
            out_layer.CreateField(ogr.FieldDefn(field_name, field_type))
            attrs_name.append(field_name)

    layer_defn = out_layer.GetLayerDefn()
    for i, poly in enumerate(polygons):
        ring = ogr.Geometry(ogr.wkbLinearRing)
        # gdal uses the (x, y) convention => (lng, lat)
        for point in poly:
            ring.AddPoint(point[1], point[0])
        ring.AddPoint(poly[0][1], poly[0][0])  # re-add the start to close
        p = ogr.Geometry(ogr.wkbPolygon)
        p.AddGeometry(ring)

        out_feature = ogr.Feature(layer_defn)
        out_feature.SetGeometry(p)

        if has_attrs:
            attrs = poly_attrs[i]
            for field_name in attrs_name:
                out_feature.SetField(field_name, attrs[field_name])

        out_layer.CreateFeature(out_feature)

    out_feature.Destroy()
    out_ds.Destroy()