undef

s1a-iw-grd-vv-20170402t100925-20170402t100950-015964-01a531-001_filter

s1a-iw-grd-vh-20170402t100925-20170402t100950-015964-01a531-002_filter

s1a-iw-grd-vh-20170402t100925-20170402t100950-015964-01a531-002_winddir

s1a-iw-grd-vv-20170402t100925-20170402t100950-015964-01a531-001_winddir