undef

s1a-iw-grd-vh-20170504t071451-20170504t071505-016428-01b35c-002_filter

s1a-iw-grd-vv-20170504t071451-20170504t071505-016428-01b35c-001_filter

s1a-iw-grd-vh-20170504t071451-20170504t071505-016428-01b35c-002_winddir

s1a-iw-grd-vv-20170504t071451-20170504t071505-016428-01b35c-001_winddir