undef

s1a-iw-grd-vh-20170918t221914-20170918t221939-018436-01f0a9-002_filter

s1a-iw-grd-vv-20170918t221914-20170918t221939-018436-01f0a9-001_filter

s1a-iw-grd-vh-20170918t221914-20170918t221939-018436-01f0a9-002_winddir

s1a-iw-grd-vv-20170918t221914-20170918t221939-018436-01f0a9-001_winddir