undef

s1a-iw-grd-vv-20170903t102527-20170903t102552-018210-01e9ad-001_filter

s1a-iw-grd-vh-20170903t102527-20170903t102552-018210-01e9ad-002_filter

s1a-iw-grd-vv-20170903t102527-20170903t102552-018210-01e9ad-001_winddir

s1a-iw-grd-vh-20170903t102527-20170903t102552-018210-01e9ad-002_winddir