Level 3 Islands

[alrichardbollans]

I'm interested in the proportion of Level-3 regions that are considered islands. Firstly, I've determined there are 369 level 3 regions in total using:

    import cartopy.io.shapereader as shpreader
    tdwg3_shp = shpreader.Reader(
        os.path.join('inputs', 'wgsrpd-master', 'level3', 'level3.shp'))

    level3_codes = []
    for c in tdwg3_shp.records():
        tdwg_code = c.attributes['LEVEL3_COD']
        level3_codes.append(tdwg_code)
    level3_codes_set = set(level3_codes)
    print(len(level3_codes_set))

but now I'm wondering if there's any reasonable way to determine which of these regions can be considered islands or groups of islands?

Obviously if 'Is.' is in the LEVEL3_NAM, this is probably a good start, but there are lots that for which this isn't the case e.g. Kazan-retto or Maldives