vectorize.py 文件源码

def simplify(filename, tolerance=0.00035):
    """ Simplify GeoJSON vector """
    # tolerance is set using GeoJSON map units. Expects decimal degrees, but should work with anything
    if tolerance is None:
        return filename
    logger.info('Updating file %s with simplified geometries' % filename, action='Updating file',
                actee=filename, actor=__name__)
    vs = ogr.Open(filename, 1)  # 1 opens the file in read/write mode, 0 for read-only mode
    layer = vs.GetLayer()
    feat = layer.GetNextFeature()
    while feat is not None:
        geo = feat.geometry()
        simple = geo.Simplify(tolerance)
        feat.SetGeometry(simple)
        layer.SetFeature(feat)
        feat = layer.GetNextFeature()
    layer = None
    vs.Destroy()